Pocketoption binary options buddy 2 0 ex4.
Scope. This document is a precursor to ALL the electronic pinball repair guides on this web site. It describes the general approach to repair, and what basic skills and equipment are needed to do general pinball and printed circuit board (PCB) repair. Updates of this document are available at http://www.pinrepair.com if you have Internet access.
IMPORANT! One of the better known pinball repair facilities contacted me and stated the number of "non-servicable" (hacked!) pinball circuit boards they receive for repair has doubled! The cause of most of this "non-servicability" was due to "hack repair" by novice repair people. This document is an attempt to help correct this problem.
Don't Over Estimate your Repair Abilities! These pinball repair documents can give you the idea that pinball circuit board repair is "easy", and make you over confident in your abilities! This is almost a guarentee you could "hack" your circuit boards and possibly ruin them beyond repair. Remember most repair facilities will NOT repair previously "hacked" circuit board.
Before attempting any pinball repair, there are some basic questions that should be asked. Simple things like, "how is the playfield glass removed?" or "how is the backglass removed?" (if you're asking these questions, even this basic document is probably beyond your skill set, and I recommend hiring a professional to fix your games).
Screwdrivers: two phillips (#1 and #2), two flat head (one small, one medium). Nut drivers: full SAE set (english units). Wrenches: full SAE set. Allen wrenches: full SAE set. A good shop light. Flexstone (EM games only) for cleaning switch contacts. Contact adjust tool (EM games only) for adjusting switch contacts.
Beyond the basic tools, a level of "common sense" is also needed when fixing games. Remember the people that designed these games were probably much smarter than you and I, so we need to trust their design (unless I tell you otherwise, ha!) If they have a connector on a board, and it is burnt, it's best to replace it (and not solder wires directly to the board, circumventing the connector, and making the game "unservicable" in the future!)
Soldering coils and switches is one thing. But fixing printed circuit boards is a whole other thing! Before attempting any Printed Circuit Board (PCB) repair, ask yourself some questions (soldering pinball coils is one thing, but replacing a soldered-in chip on a circuit board is another):
Do you have any soldering experience? Do you have any PCB soldering experience? Do you have the proper tools for PCB soldering? Do you have the patience required to go "slow and careful"?
If the answer is "no" to ANY of these questions, STOP! Do not work on circuit boards! Send them out for repair to a professional. In the end, much more money will be saved having the boards fixed professionally, then attempting to repair them yourself.
Keep in mind some pinball circuit boards are not replaceable! So if a board is made "non-serviceable" (unusable), a lot more money can be lost than a professional repair would have cost in the first place. In some cases, it is possible to make a game "junk" if a non-replaceable circuit board is ruined.
This is the key point to this document. Do not think because all the procedures here look easy and anyone can do them! Do NOT become over confident. A "hack" repair can RUIN a circuit board. And most repair facilities will not fix circuit boards that have been unsuccessfully repaired ("hacked") by someone else.
Soldering a new coil in a game is one thing. A sloppy job won't really affect much. Sloppy soldering on a circuit board is another matter however. A circuit board can be totally ruined with bad soldering. Also the equipment and techniques are a bit different on circuit boards than on coils.
I remember when I first learned to solder. My dad taught me with a soldering pencil, some paper clips, and some rosin core solder. I was probably 10 years old, and I thought it was fun! What he had me do first was make a box out of the paper clips. Using needlenose pliers, I constructed one side of the three dimensional box. Then I soldered the points where the paper clips came together. When I was done, it was a pretty nifty 3-D box, and I was proud.
Nostalgia aside, this was a good first experience. It taught me how to solder, at the expense of only some paper clips. If one has novice soldering skills, start small and practice! Sacrifice some paper clips and make a "box".
If a pinball machine is in the future plans, then the owner needs to know how to solder! Knowing how to do basic soldering of wires onto solenoids (coils) and switches is a must. Due to the vibration of solenoids and players in a pinball machines, wires do break off coils and switches. It happens, and the owner will need to know how to deal with it!
Basic soldering is pretty straight forward. Get a soldering station and some good quality solder (as decribed below). Having the right tools is 75% of the job! And remember, a good solder job on a coil or switch starts with a good *mechanical* connection. That is, the wire should be mounted to the coil or switch lug before being soldered, and stay put! After that, soldering the wire is just a matter of heating the wire and the lug *together*, and then applying a small amount of solder. The solder should be applied to the wire or lug, and *not* directly to the soldering iron's tip. This ensures the solder will flow over the wire and the lug, and that they are heated to the right temperature. The soldering iron can then be removed from the joint. Now keep the solder joint steady while it cools, otherwise it could produced a "cold" solder joint (one that does not conduct electricity freely).
Once this basic soldering is mastered, the next step (maybe!) is solder on a Printed Circuit Board (PCB). If one has never soldered a PCB before, don't try your first attempt on a (expensive!) pinball CPU or Driver board! Practice on some junk boards first.
Junk circuit boards are easy to get. Video game collectors can often provide some junk JAMMA games board or other boards. Maybe there's an old PC computer (which you couldn't give away!) that's could be used. Practice circuit boards aren't that hard to find. You just gotta look. Even if one has to pay for some junk boards, it's well worth it.
Good circuit board repair work requires good light! Good light is cheap. If there isn't good light in the workshop, go to the hardware store and buy some 4 foot dual florescent lamp fixtures (about $10). I personally like florescent light for repair work. It's cheap (to buy and run), and it does a good job. Florescent light is best because it is "whiter" than incandescent light.
An incandescent version of the nifty magnifier lamp.
Buy a good magnifier. A good magnifier allows examination of circuit boards in great detail, to view repair work quality. There are two types of magnifiers available. One is worn on the head, and it requires an external light source. To focus, move your head to a certain distance from the viewing object. The other (more desirable in my opinion) magnifier is on an adjustable "arm", and has a built in light source. This is what I personally prefer, and I find it extremely useful for finding circuit board defects. MCM Electronics (800-543-4330) sells these, part number 21-935 for $49, but it's often on sale for $39. This is a nice version with a built in circular florescent lamp. There is also a cheaper version with a standard incandescent light bulb for about $29 (often on sale for $19), part number 22-3995, but the florescent lamped model is much nicer.
When doing PCB repairs, it is important to buy the right tools! Yes, this will cost money. There is NO way around that. But do NOT buy cheap tools. For example, a good soldering station can last a lifetime, and make soldering SO much easier and better. Don't be cheap (unless I suggest it!)
Buy a Good Soldering Station. Your dad's old soldering gun isn't going to work for soldering circuit boards. A GOOD soldering station is needed. Melting metal in close proximity to delicate electronic components requires the right tool. When working on printed circuit boards, a precise amount of heat is applied for a short period of time to a very precise area. The best way to do this is with a quality soldering station. Expect to spend up to $50 to $150 for one. Soldering stations are nice because they allow you the soldering temperature to be exact. Also they are grounded nicely, to isolate the iron from its power source (this protects static sensitive chips).
Left: Tenma #21-7930 with LED temperature display. This costs about $40 to $80. A great station for the price. Right: Weller/Ungar model 921ZX again with a LED temperature display. This costs about $90 to $120.
Temperature Control is Important, not Wattage! The important thing to get in a soldering station is temperature control, and not some goofy variable rate that has no reference point (like "1 to 10"). An actual temperature range is important. Soldering is best done at 600 to 700 degrees (personally I usually solder at about 650 or 700 degrees), but a decent soldering station is usually adjustable from 300 to 900 degrees. A soldering station that doesn't provide a temperature guage is probably varying the wattage, and not the temperature. This is far less useful.
For cheap soldering irons, the wattage of the iron is a measure of the power that is used to heat the iron. So a 25 watt soldering iron is always running at that level of power consumption (like a 25 watt light bulb would), and is ALWAYS generating heat. The soldering iron's tip absorbs the heat. As long as power is supplied the tip will continue to get hotter until it reaches "equilibrium" (the maximum temperature where heat will be conducted to the air at the same rate heat is applied to the tip). As soon as a soldering iron's tip makes contact with metal, heat will transfer from the tip quickly. The higher the wattage iron, the quicker the tip will heat up again. When a cheap soldering iron is idle, it is MUCH HOTTER than it needs to be for soldering. But the moment you place it on metal for soldering, it cools down. For this reason, if not using a cheap soldering iron for more than 5 minutes, turn it off. Otherwise it will get too hot and ruin the iron's tip (at minimum), or apply too much heat to the solder joint (at worse).
The above is why cheap soldering irons are bad; there is no way to control the actual temperature of the iron! That's why a good soldering station is really a must. The right temperature can be dialed in. Then the station will monitor itself, turning power to the station's soldering tip on and off as needed to maintain the desired temperature. Good soldering stations also provide a level of isolation so static sensitive chips won't be easily ruined by the soldering iron.
Tenma's soldering station with LED temperature display #21-7930 (formerly #21-147) is available from MCM Electronics (800-543-4330) for $75 ($40 on sale). Tenma also has a digital display version of this station for $100 (often on sale for $60) #21-7935. Also get some replacement soldering tips, screwdriver "chisel" style #21-7983 (formerly #21-927, 3/64" wide chisel tip for circuit board work) and #21-926 (1/6" wide chisel tip for bigger jobs like coils) for $2.49 each. Then even sell a complete replacement grounded iron (with tip) for these two station #21-7936 (formerly #21-151) for $10.
Finally Weller's WES50 soldering station is also available from MCM for about $110 (often on sale for $100). This model has adjustable temperature range from 350 to 850 degrees (though the scaling is strange). The Weller brand will cost a bit more, but is probably worth the extra money.
Using good solder is VERY important in circuit board repair. The best solder is made by Kester (USA made). Radio Shack solder is Kester solder (but with the Radio Shack label). Here are the solder specs you need:
Rosin core flux is very important. Any other type of flux will not work for circuit board repair. For example, acid flux is designed for plumbing work, not electronics! Most hardware stores only sell 95/5 lead free solder, which won't work for circuit board repair. Radio Shack's solder is made by Kester, and is quite good.
When doing circuit board repair, a method of desoldering old parts is also needed. When pricing desoldering tools, make sure to also price new tips! (Obviously this does not apply to desolder braid). Often the price of a new tip can be very expensive. And a new tip will be needed at some point. It really is a good idea to buy an extra tip or two when purchasing a desoldering tool.
Replacement tips come in a variety of hole sizes. The "standard" hole diameter is about .040". This size will work for most pinball desoldering applications. Personally I tend to go .050" or even .060", as desoldering .156" Molex male header pins are usually too big for a .040" tip.
Desolder Braid. Desoldering braid is a very common and cheap desoldering tool. Available from Radio Shack, part number 64-2090, for $2.29. Desoldering braid is just flexible copper braid, about 1/4" wide. Just put the braid over the joint you are desoldering, then put your hot soldering iron's tip over the braid. As the braid heats up, it will "absorb" (wick) the melted solder from the joint. When you're done with that joint, move down the braid to a fresh spot (you can *not* reuse the same area of the braid again).
Left: the Radio Shack vacuum desoldering pump, known as the mini "Soldapullt". I use one all the time! It works great and it's inexpensive. Right: the Radio Shack desoldering iron, and an extra "iron clad" tip.
The Radio Shack Desoldering Iron. For the average hobbyist, this is an usable desoldering tool. The Radio Shack desoldering iron is part number 64-2060, $9.99. It is simply a 45 watt soldering iron with a hollow tip, and a red suction bulb. After letting this iron warm up for about 15 minutes, compress and hold the red bulb. Then put the hollow tip over the joint to desolder. After the solder has melted (a couple seconds), release the red bulb, and the solder will be sucked from the joint (this theory is how expensive desoldering stations work). An easy one handed operation that requires minimal practice.
But this style of desoldering tool comes with the same warning as non-adjustable temperature soldering irons; the amount of heat applied can *not* be adjusted! Because of this, the Radio Shack desoldering iron can be dangerous. Too much heat, and the traces and solder pads can delaminate from the circuit board! Just keep this in mind. Remember, it is a 45 watt desoldering iron, so it generates *lots* of heat. With a little practice, the Radio Shack desoldering iron can work well. It's hard to beat for the price, and I personally find it easier to use than most other low-cost desoldering tools. But too much heat can be applied with this tool, making it dangerous for the "newbie". Because of this, I would not recommend this tool for first time users unless they practice a lot on junk board first.
Also make sure to buy extra tips for this desoldering tool. They sell two styles of tips; get the "iron clad" version, which costs about 70 cents more, part number 64-2062, $1.99 (the iron clad version will last much longer than the standard version). A clogged or enlarged tip on this tool will render it useless.
Desoldering Vacuum Pumps (Soldapullt); Newbie Recommended! A very common desoldering tool is known as the "Soldapullt". It's a large syringe type desoldering device with a Teflon tip (get a replacement Teflon tip when buying this tool). Lots of technicians use this desoldering pump because it's cheap and works well. The downside to this tool is it requires TWO hands (one to hold your soldering iron, and the other to hold the Soldapullt). You are better off getting the bigger Soldapullt III, but Radio Shack also sells a mini blue Soldapullt version (part number 64-2098, $7.99) that works well. The larger Soldapullt III comes in normal (blue) and anti-static (silver) versions. The anti-static version would be preferred. MCM also sells an low-static Soldapullt, part number 21-4700, for $9.99. Personally I use the blue Radio Shack version all the time and find it to work great! When it breaks I throw it away and buy another. I use it on all kinds of things from delicate circuit boards to removing solder from coil lugs.
The biggest advantage to a Soldapullt tool is a soldering station can be used to heat the joint being desoldering. This means the desoldering temperature can be controlled via the soldering station. This is probably the single biggest advantage to using the Soldapullt desoldering tool (aside from price). Because of this, I highly recommend the Soldapullt tool for first time "newbie" repair people. But remember, practice is necessary to use it! So find some junk boards and try it out (instructions on how to use this tool are below).
Better (more expensive!) Desoldering Irons. If the money is available, or one is doing lots of desoldering, a "real" desoldering station should be purchased. These consist of a small suction pump, connected to a soldering iron with a hollow tip. They work much like the Radio Shack desoldering iron, except there is an electric air pump instead of a manual suction bulb, and the soldering tip is temperature controlled. These desoldering station will use the least amount of heat, and do the best job desoldering. Also available are desoldering stations that uses compressed air instead of a dedicated electric air pump. These work the best (since the air source can be a larger 100 psi air compressor), but are obviously not as portable.
I can't stress how much better these units are than the previously discussed and less expensive desoldering tools. If working on any games that require a fair amount of desoldering, these tools will make the job FAR easier, faster, and less problematic.
The XYtronic "One Shot" #2008 for about $99. I can not stress how good this desoldering tool really is, especially for the price! I use it "on the road" as a small and convenient desoldering tool, and it works great.
Hakko sells a nice desoldering iron model 808 for about $175. It has a self-contained vacuum pump, and is about the size of the soldering gun. This is a great desoldering tool for the price. I personally use this tool as a "on the road" portable desolder station, and I am amazed how well it works. Temperature is adjustable via a small pot, but it's more designed to be set once and not constantly readjusted. For the price this is a great desoldering tool. Takes about 5 minutes to warm up and is ready go. Just put the tip over a solder pad, wait a second for it to melt the solder, then pull the trigger. When finished and the tool cools, remove the spring loaded solder collector tube and clean out the old solder. That's about all there is to it. I have been using this tool for several years and it works great. Just make sure it warms up for 5 minutes before using or the suction tube will clog.
The Tenma desoldering station. Note the temperature LED.
Tenma also makes a nice desoldering station, model 72-6340, for about $299 ($250 on sale) at MCM Electronics (800-543-4330). It has adjustable digital temperature from 410 to 900 degrees. It is a self contained station with its own compressor.
Other Desolder Parts to Buy. No matter what desoldering tool is purchased, make sure to get some extra tips. Again I would recommend .040" hole diameter, or even .050".
Also all desoldering stations also use some sort of filter to keep the old solder from getting into the air source (this filter is usually located in the solder collection tube). The filter could be as simple as a (100%) cotton ball (do NOT use synthetic cotton, as it will melt!) Have some spare filters around, and be prepared to replace this filter every now and then. Another replacement item is the rubber gasket that seals the solder collection tube to the "Y" adaptor. With time these dry out and fall apart. So it's not a bad idea to have a few of these rubber gaskets around too.
Finally, many desoldering stations also offer a declogging "toolkit" that includes a set of miniature round files. These are used to clear the desoldering tip and adjacent "Y" adaptor of any stuck solder. It's a good idea to have one of these toolkits too, if it didn't come with the new desoldering station.
Buying a Used Desoldering Station (Ebay). Often good quality desoldering stations can be found on Ebay. Just be careful when buying in this environment. Almost guarenteed the station will need a new tip, a new filter, and a new solder collection tube gasket, and that the original declogging "toolkit" is missing. Sometimes the heater element or compressor can be bad too! So ask questions and check out the price of new tips and other parts. Also remember, a used desoldering station is usually being sold for a reason (it doesn't work well any more!) But good deals can be found because many people don't realize that the tip and collection tube gaskets do wear out and need to be replaced every now and then, and that the "Y" adaptor can clog! (especially if the desoldering station was used before it was hot).
"What is a DMM?", you ask. DMM stands for Digital Multi Meter. It is THE tool you will use the most when repairing electronic pinball games. This tool is used more than any other in pinball repair (other than a soldering iron!) DMM's do lots of good things: Test for "continuity" (if two things are directly connected). Measure voltage. Measure resistors. Test diodes Test transistors. Measure capacitance (on some DMM's)
An electronic pinball game repair should not even be attempted without a decent DMM. It's probably the single most valuable tool. The best name in DMM's is probably Fluke. But for pinball repair purposes, any decent brand will probably work fine.
DMM Features. For the most part, "more is better" when it comes to DMM's. All meters will test voltage (AC and DC), and resistance (ohms). Here are some other options to consider.
Continuity beeper ("buzz tone"). Diode test.
Capacitance test (up to 20,000 mfd, anything less is far less useful). Transistor test. Logic probe.
True RMS (good for very accurate AC voltage measurements only). RS-232 communication (for your computer). Temperature measure.
Left: Fluke 83 auto ranging DMM. Notice the simple dial selector and the yellow rubber shock case. This meter costs about $250. Right: Tenma 72-4025 DMM. This is NOT an auto ranging meter (specs here ). Notice the dial selector has A LOT more settings! This meter costs about $70, and came with the gray rubber shock case. This is a great meter, as it does everything, and is priced very nice.
Auto Ranging? Auto ranging meters are great for beginners. Manual ranging meters require the user to know something about the part they are testing. For example, if testing a 1 meg ohm resistor, but the meter is set to the 10k ohm range, the resistor will show as "open" (null resistance). The meter needs to be set to a higher resistance range for this test. This means the resistor or schematic needs to be examined before testing it, to figure out what its value *should* be (based on the schematics or the resistor's band colors), Then the DMM is set accordingly.
In the case of an auto ranging meter, it does an initial test on the resistor, and figures out the correct range. All the user needs to do is to set the meter to "resistance", and it figures out the rest.
What are the Disadvantages to Auto Ranging DMM's? Auto rangers aren't for everyone, as they have some disadvantages. First is cost. An auto ranging DMM will cost more. Second is speed. It takes a moment longer to test a component on an autoranging DMM. This extra time means nothing, *unless* using the meter to measure a "pulsing" value. For example, a voltage that goes up and down over a short period of time. An auto ranging DMM won't be fast enough to read the voltage, set it's range, then read the voltage again and display it. A manual range DMM would work much better here. For this reason, most "seasoned" repair people do not want an auto ranging DMM (note many good auto ranging DMM's have the ability to turn the auto range option off, and set the range to test manually).
DMM Leads and Clips. Some DMM's come with threaded probe ends on the red and black wire leads. These allow aligator clips to be screwed to the ends, or other nifty attachment clips, to make using a DMM easier. I highly suggest this type of leads. If your meter doesn't have the threaded probe ends, at minimum get some 24" mini alligator clips (Radio Shack #278-1157, $3.99) or 30" alligator clips (Radio Shack #278-001, $3.69) that can be clipped onto the probes of the DMM.
Cheap DMM's are No Bargain. Trust me, I've been there. Buy a decent meter! Cheap ones break easily, and can give suspicious readings. Having a nice DMM is something will be appreciated. For $60 or more, a pretty nice meter can be bought. I find that if the meter has a rubber "shock case" option, buy it (if it doesn't come with the meter). Also the meters that have an available "shock case" seem to be the better (more durable) models (the ones without shock cases tend to be "disposable").
"What is a logic probe?", you ask? Basically, a logic probe is a small, cheap device that shows a circuit is either at zero or +5 volts. Yes, some DMMs can do this too, but if the circuit is running at any speed, the DMM (manual range or not) can not keep up. The logic probe's job is to show these voltages, and the pulsing relationship between them.
To understand why these "pulses" are important, some basic computer hardware concepts need to be understood. Simply put, a electronic pinball game is a computer. Computers (at a low level) can only deal with zeros and ones. A "zero" is basically zero volts DC (.8 volts or less). A "one" is basically +5 volts DC (2.4 volts or greater). The relationship between these two signals (voltages) is important. How fast or often a circuit goes from zero to +5 volts can determine how a circuit works. A logic probe can show if a particular pin on a chip is low (zero volts), high (+5 volts), or pulsing. The pulses can be "low pulses" or "high pulses" too. The logic probe shows this with three LED's, and sometimes a buzz tone too.
Unfortunately, a logic probe only indicates state changes (a zero or a one, which is 0 volts to .8 volts, or 2.4 volts to +5 volts, respectively). It is up to you to know if these are the expected changes!
Are All Logic Probes the Same? Basically speaking, "yes". Most logic probes will have three LED's (low, high, pulse), and a switch (CMOS/TTL select). Some logic probes are faster than others. For pinball, get one that can test up to 5 mHz (or faster), but most can do that. Also some probes emit a tone in addition to the LED's, which is a nice feature.
Radio Shack used to sell a decent logic probe at for $17.99, part number 22-303, but apparently Radio Shack is discontinuing these. MCM Electronics (http://www.mcminone.com) also sells a nice Tenma logic probe with memory, part number 72-190, for less than $25.
The Wittig Technologies osziFOX probe in action.
The Best Logic Probe. By far my favorite logic probe is made by Wittig Technologies (wittig-technologies.com). It's called the osziFOX Probescope, and it's a "probe style oscilloscope". It is a 5mHz (DC band width, other specifications available here) logic probe with a small LCD display screen, which draws a picture of the signal. It can even be interfaced it a computer through the serial port (giving a larger, more oscilloscope usage), or to a Palm Pilot IIIc! It runs on 9 to 13 volts DC (much like a regular logic probe). A pretty neat device, available from Test Equipment Depot (1-800-517-8431) for $ 69.00, or directly from the manufacturer at wittig-technologies.com. It gives a nice picture of what the signal pulses look like. Though I still recommend having a "regular" logic probe, this device is really cool and more like an oscilloscope. For someone just starting out in repair, this device really helps "see" what signals should look like. I personally find the "picture" which this probe draws as very useful (though it is no substitute for a real oscilloscope, which shows a picture of the signal in a time relationship).
Though a good set of hand crimpers is not an electronic evaluation or measuring tool, it is needed for nearly all pinball repair. A hand crimper allows the easy and precise replacement of Molex connector pins, which are used extensively in pinball machines. Also needed will be connector pin extractors, for cleanly removing connector pins from their housing.
The BCT-1 hand crimper for crimping Molex connector pins. Picture by aeroelectric.com.
Here are the minimum connector tools required: Terminal Pin Hand crimper. These are used for all the different styles of Molex terminal pins. Aeroelectric's terminal tool BCT-1, available from aeroelectric.com/Catalog/tools/tools.html (about $32, good for all pin sizes) is an excellent crimper, or Molex crimper #63811-1000 (inexpensive but versatile, type 6), or Molex crimper #11-01-0015 (excellent but more expensive, type 3), or Waldom/Molex crimper WHT-1921 (good yet inexpensive, for .100"/.062" and .156"/.093" pins), or Waldom/Molex crimper WHT-1919 (really for .156"/.093" pins only), or Amp 725 (probably no longer available), or even Radio Shack #64-410 (last resort, not very good and not recommended). .093" Round Pin Extractor: Molex part number 11-03-0006, or Waldom/Molex part number WHT-2038, or Radio Shacks part number 274-223 (in this case the Radio Shack tool is pretty good). .062" Round Pin Extractor: Molex part number 11-03-0002, or Waldom/Molex #WHT-2285. Optional, as this size is not used nearly as much as the .093" size. .156" terminal pin extraction tool from card edge connector housings: I only use this for Gottlieb system80 games, so this is optional unless working on those games. Made of spring steel, Molex part number 11-03-0016 (rubber handle version), or Molex #11-03-0003 (bare bones version).
The BCT-1 hand crimper's different jaw sizes for different size connector pins. The "C", "D", and "E" pockets are used to crimp the bare wire to the Molex connector pin. These pockets cause the end of the pin's wire grip wings to curl over and dive into the center of the wire strands. Pockets "A" and "B" have a smooth circular shape, and can be used to crimp the terminal pin's insulation-grips into a "bear hug" around the wire's insulation, but Molex suggests using the C,D,E pockets for insulation too. Picture by aeroelectric.com.
For more details on connectors, crimping and crimpers, please see marvin3m.com/connect for details.
A Molex connector pin properely crimped. Picture by aeroelectric.com.
Though this isn't all the symbols ever used on a schematic, these will certainly help.
All the symbols needed? Maybe.
Transistors are used extensively in pinball. There are several types used, but we will talk basics here to keep it simple.
What is a transistor? Transistors are tiny components which amplify small signals using low voltages. Transistors are basic components in all of today's electronics. They are just simple switches that we can use to turn things on and off. Even though they are simple, they are the most important electrical component. For example, transistors are almost the only components used to build a Pentium processor. A single Pentium chip has about 3.5 million transistors.
The transistor has three legs, the Collector (C), Base (B), and Emitter (E). The Base (B) is the on/off switch for the transistor. If a current is flowing to the Base, there will be a path from the Collector (C) to the Emitter (E) where current can flow (the switch is on). If there is no current flowing to the Base, then no current can flow from the Collector to the Emitter (the switch is off).
When current is put into the Base, it changes the voltage characteristics of the entire transistor, and so it is possible to control the current flowing from the Collector to the Emitter. So a small change of current on the base, results in a large change between the Collector and Emitter.
Transistor symbols: Note the arrow pointing in or out, signifying an NPN or PNP transistor.
The arrow in the transistor symbol is always on the emitter leg, and points in the direction of conventional current flow (positive to negative). The easy way to remember which is which:
NPN = N ot P ointing i N . The NPN transistor's arrow is not pointing in. PNP = P ointing i N P ointer. The PNP transistor's arrow points in.
NPN and PNP transistors function in essentially the same way, just the power polarities are reversed. This means a NPN transistor has a higher frequency response than a PNP transistor (because electron flow is faster than hole flow). When a NPN transistor is doing-its-thing, there is always a constant 0.6 volt drop between the base and emitter. That is, the base is always about .4 to .6 volts more positive than the emitter. We will see this come into play when we test transistors using a DMM (digital multimeter).
Bipolar transistors are often used in pinball, and are a current driven device. This means a very small amount of current flow from the emitter to base can control a relatitively large current flow from the emitter to the collector.
Darlington transistors (for example, the TIP102 and TIP36c) are actually two transistors in one package. This is achieved by arranging the two transistors so the emitter of one is driving the base of the next, and by connecting the collectors together. This is known as a Darlington pair, and can be used as any single transistor would be used (common emitter, emitter follower, etc.) The advantage to this style of transistors is it has a larger on-state power dissipation (which means these Darlingtons can handle lots of current for driving big pinball coils such as up-kickers and flippers). The down side to Darlington transistors is reduced power-on/power-off speed.
How a smaller current turns on a larger current in a NPN transistor. A Transistor can be thought of as a device that is active in only one direction: It can draw more or less current through its load resistor (sometimes referred to as a pull-up resistor).
This above diagram shows how an NPN is turned on. When the base is turned off (connected to ground), there is no current put through the transistor, so the transistor is off. When the base voltage is raised, it turns the transistor on, completing the higher 12 volt's path to ground (and energizing a pinball coil).
Like it or not, if doing circuit board repair, one must know "what side is up" on logic chips. This document will not give you all the details on logic chips, but does provide the basic things info needed.
Two different chip makers mark pin one differently. The chip on the left (74LS107) has a small dot impressed to signify pin one. The chip on the right (74LS02) has a notch, and pin one is always to the left of the notch (as facing the chip's top side, with the notch up). The chip on the left also has a date code of "8146"; this chip was made during the 46th week of 1981.
Pin One: where is it? Every chip has a "pin 1". Find pin one, because this is the reference point for all the other chip pins. Also pin one is the reference point to how the chip should be inserted into the board or socket. Putting a chip in "backwards" will definitely cause the chip to fail!
Pin one on all chips is marked somehow. Often there is a small dot impressed into the case of the chip signifying pin one. Other times there is a notch in the chip showing pin one. In this case pin one is always to the left of the notch (as facing the chip's top side, with the notch up). Sometimes chips have both a notch and an impressed dot!
Pin one is also marked on all sockets too. Again, sockets generally use the "notch" in a cross bar for indicating pin one. This notch helps when replacing a chip, so it is not plugged in backwards! Some sockets use an indented cross bar to indicate pin one, instead of a notch.
Often the circuit board itself is also silk screened to show pin one for each chip. Again, this could be a box that shadows the chip, with a notch in one side of the box to show pin one. Or it could be as simple as a "1" or a "dot" next to the chip's pin one leg.
A 1996 ECG Master Replacement guide. You don't need the latest copy, as most chips you will be looking up have been around for a while.
Buy a NTE or ECG Master Replacement Guide. Any electronics dealer that sells NTE or ECG parts will have one of these guides available. Often older copy of this guide can be had for free, or just a couple dollars. The latest version is not needed, as most chips being referencing have been out for a number of years.
Information from the ECG Master Replacement guide. Note the Ground (GND) and +5 volt power (VCC) pins are shown, along with what the chip does and what the other pins do. Shown is a 7406 or 74LS06 chip.
This replacement guide is not needed so much for the chip replacement info (though that is certainly helpful!), but for the chip "pin out" info in the book. It will show for each chip, what the chip does, and what each pin does. This is handy information to have. For example, the Ground (GND) pin on many chips is different, as is it's logic power (VCC) of +5 volts. This info is needed when doing circuit board repair, as it is very helpful to know where ground and power (+5 volts) is on any chip.
Online Chip Reference Guides. There are also some online chip reference guides with chip pin outs. Though not nearly as good as the ECG/NTE replacement guides, the online reference is quick and easy (and free!). Check out http://www.embeddedlinks.com/chipdir and http://www.twinight.org/chipdir/n/index.htm.
Explaination of TTL Chips. The most common chip used in pinball circuits is the TTL chip. TTL chips are a standard set of sub-circuits used in circuit board designs. The TTL family of integrated circuits was introduced about 20 years ago by Texas Instruments. TTL stands for Transistor to Transistor Logic , which signifies that two transistors are used to drive each output of each chip, one for pulling the output down to a low level, and one for pulling the output up to a high level. Chips made using TTL technology are faster than the older RTL ( Resistor Transistor Logic ) and DTL ( Diode Transistor Logic ) families of integrated circuits, and they consume more power than the MOS ( Metal Oxide Semiconductor ) technology used in most VLSI ( Very Large Scale Integrated circuit ) chips.
The TTL family has at least six sub-families which offer different speed/power tradeoffs. These are summarized in the following table, where they are listed in roughly the order in which they were introduced:
Family Delay (ns) Power (mW) basic 10 10 Low-power L 35 1 Schottky S 3 18 Low-power Schottky LS 9 2 Fast F Advanced Schottky AS 1.5 10 Advanced Low-power Schottky ALS 4 1 High-speed CMOS HCT High-speed CMOS HC.
The term Schottky refers to a technology for making faster transistors. In each generation of the TTL family, the low power representative is about 3 times slower than the other member, but consumes about 1/10 the power. Today, the low-power Schottky (LS) subfamily is the most widely used member of the TTL family.
TTL chips have a standard naming convention of 74xx or 54xx. All manufacturers of TTL chips use this common naming system, as exemplified by the chip name SN74LS00. The prefix SN indicates that the chip was made by Texas Instruments; other manufacturers have their own prefix codes. However if the remainder of the chip name matches, the chips should perform exactly the same function. Additional one letter codes may be added as prefixes or suffixes to this code, for example, RSN indicates radiation hardened chips made by Texas Instruments, and SNM indicates the use of quality control procedures specified by the military specification MIL-STD-883.
The numeric code 74xx indicates that the chip conforms to the requirements of the civilian computer industry, being able to operate over a temperature range of 0 to 70 degrees C, while the code 54xx indicates the ability to operate over the more extreme temperature range of -55 to 125 degrees C required by many military and industrial applications. The letters LS (in the example SN74LS00) indicate which subfamily the chip belongs to. Finally, the last two digits indicate the logical function performed by the chip.
7400 (or 5400) Quad 2-input NAND gates. 7402 (or 5402) Quad 2-input NOR gates. 7404 (or 5404) Hex inverters. 7408 (or 5408) Quad 2-input AND gates.
The descriptions of these circuits are based on the details given in The TTL Data Book published by Texas Instruments. Equivalent data books are published by all of the major chip manufacturers such as Signetics, National Semiconductor, ECG and NTE.
A 7400 chip.
For example, consider the 74LS00 chip; this has four NAND gates. The inputs of the first NAND gate are p1 and p2 , and its output is p3 . The inputs of the second NAND gate are p4 and p5 , and its output is p6 . The remaining NAND gates are connected to p8 through p13 , and pins 7 and 14 are ground and power (respectively), and are not given names in the specification.
HCT and HC Chips. Most pinball applications use "LS" TTL style chips. But today LS chips are becoming harder and harder to find. But the good news is the newer HCT chips will directly replace LS technology in most (if not all) cases. The "T" in "HCT" indicates a TTL LS level interface (minimum 2.4 volts input for a logic "1"), even though HCT is a CMOS device. HCT chips will usually substitute for "regular" TTL chips too (like say a 7400 chip).
However don't sustitute HC for LS or any other TTL family without looking at the specifications, as HC chips are not compatible with TTL chips. They are high speed CMOS but with no TTL interface (HC chip expect much higher input levels for a logic "1" and a much lower input level for a logic "0"). The HC parts have similar interface levels to the old 4000 series IC's, except the HC parts usually run much faster.
CMOS Chips. CMOS chips usually have the numbering convention of 40XX or 45XX. The CMOS (Complimentary Metal Oxide Semiconductors) logic family is a step beyond the TTL family. It's most notable feature is that it can operate at much higher voltages (over +12 volts) than a TTL chip. Also it is ANALOG in it's performance, compared to the DIGITAL nature of TTL. TTL's are considered digital as they have only 2 valid states: Low (0) and High (1). CMOS have states that are proportional in nature.
For example, compare a CMOS 4069 Hex Inverter, which is a functional equivalent of the 7404 TTL (not "pin compatible", which mean you can't just plug a 4069 in place of a 7404). In this case, we know if a given input has a state of high (1) on the 7404 TTL, then it's output would be inverted to be low (0). After all, this is what a "Hex Inverter" does! But the CMOS 4069 would be different; first it's input state could be a voltage range from 0 to the operating voltage, say in this example, +12 volts. So if the input voltage for a given gate was +4 volts, then the output would be +8 volts, which is the inverse proportion of the input relative to the operating voltage (12 volts).
CMOS is useful for handling audio and video outputs, or any situation where the input voltage is not just a "black and white" zero or one.
3d. Component Explainations and How to Test Components Using a DMM (voltage, continuity, resistance, capacitance, diodes, transistors, chips).
A DMM has two leads, a black and a red lead. The black lead should connect to the "COM" (common) connector on your meter. This is important when measuring DC voltage.
Continuity testing will be the most basic chore of a DMM. Continuity testing check two points to determine if they are directly connected to each other. Continuity is defined as "zero ohms resistance", but in reality, most DMM's define continuity as anything below 75 ohms of resistance.
For example, if I had to remove a chip from a circuit board and install a socket, I always test each pin of the socket to make sure it connects to the circuit board trace it is soldered. This ensures I haven't broken or cracked a trace while removing the old chip.
With my DMM set to "continuity", I can "buzz out" two points with the DMM's test leads. With one lead of the DMM on a socket pin, and the other DMM lead on the trace that connects to the socket, there should be a "tone" (or "buzz") indicating continuity. No buzz means these two points aren't connected (or are connected with high resistance).
If your meter does not have a continuity setting, just use the lowest range of resistance ohms for this test. Zero ohms (or close to zero, like less than 1 ohm) means you have continuity. The disadvantage to not having a continuity setting is you must LOOK at your meter to see if you have continuity. With a continuity setting, one only needs to HEAR the buzz tone, instead of seeing the meter. This makes checking continuity on a number of test points much faster.
Testing Resistance (Testing Resistors). Resistance testing is much like testing for continuity, but usually the value of a resistor is being tested. If a manual range DMM is used, one will need to know the basic value of the resistor being tested (so the DMM's ohm range can be set accordingly). If the DMM is set to the 10k range, and the resistor being tested is 12k ohms, the meter will show no value.
Most resistors can be tested "in circuit". That is, with them soldered right in the circuit board (without removing them). Just put the leads of the DMM on either end of the resistor.
Are Resistors Polarized? The short answer is "no", resistors are not polarized. When they are being measured, it does not matter how the red and black leads are positioned on the resistor. Likewise, when installing a resistor, there is no "incorrect" orientation (it can be installed either way).
A Radio Shack resistor color decoder. Well worth the $1.19 for easy conversion of a resistor's colors.
Resistor Color Chart. Here is a resistor color code chart for the first three color bands of any resistor. The third band is the "multiplier" band:
Resistor Color Codes Band 1,2,3 Color Band 1,2 Value Band 3 Value (Multiplier) Black 0 1 Brown 1 10 Red 2 100 Orange 3 1 000 (1k) Yellow 4 10 000 (10k) Green 5 100 000 (100k) Blue 6 1 000 000 (1meg) Purple 7 Grey 8 White 9.
Fourth Band Colors. The last (fourth) band is the tolerance band (how accurate the resistor is to its stated value), plus or minus. Here are those colors: No 4th band = 20% tolerance Silver = 10% tolerance Gold = 5% tolerance Red = 2% tolerance.
Yellow, Purple, Black, Silver = 47 ohms, 10% tolerance Yellow, Purple, Brown, Silver = 470 ohms, 10% Yellow, Purple, Red, Silver = 4700 (4.7k) ohms, 10% Yellow, Purple, Orange, Gold = 47,000 (47k) ohms, 5% Yellow, Purple, Yellow, Silver = 470,000 (470k) ohms, 10% Yellow, Purple, Green, Red = 4,700,000 (4.7meg) ohms, 2% Yellow, Purple, Blue = 47,000,000 (47meg) ohms, 20% tolerance (since there is no fourth band)
With the above info, a manual range DMM can be accurately set. Remember, always pick a DMM range higher than the resistor value being tested, but never lower. If a resistor is more than 10% above or below it's intended value, replace it (even though some resistors are rated at as much as 20% out of tolerance).
On-line Resistor Color Chart. I have a nifty online resistor chart at http://marvin3m.com/resist for those that want to experiment with resistor colors and values in a "point and click" fashion.
Resistor Wattage. The bands of a resistor do not indicate the resistor's wattage. Small logic resistors are typically 1/4 or 1/2 watt. Resistors used to handle supply voltages are usually larger 1 to 10 watt resistors. Generally speaking, the larger the physical size of the resistor, the higher the wattage and the higher current it can handle. If an application calls for a 2 watt resistor, only a 2 watt resistor or HIGHER will work (that is, 2 or 5 or 10 watts). Installing a lower wattage resistor will surely cause the resistor to become very hot and burn (making it go open or change resistance value). Often higher wattage resistors are marked indicating their wattage (i.e. "5w" for 5 watts). Smaller resistors are usually not marked with a wattage.
Measuring a diode with the black DMM lead on the banded side of the diode.
Diodes are used extensively in pinball. In solidstate pinballs, there should be a diode on every coil (some games, like the Williams WPC games, have the coil diodes mounted on the driver board though). The coil diode is used to suppress the the back EMF (Electro Magnetic Field) voltage. When the power to a coil is suddenly switched off, the collapsing magnetic field generates a voltage across the coil which tends to maintain the current. As the switch off is usually very fast, the voltage can reach several hundred volts. This high voltage and current can travel back to the game's driver board, damaging board components (usually the coil's driver transistor).
Testing Diodes. A diode can not always be tested in-circuit. Often (but not always) one lead of the diode needs to be remove (unsolder) from the circuit board to get a good test. This also applies to testing coil diodes (one diode lead needs to be removed from the coil). When testing diodes, use the diode test of the DMM.
Put the black lead of the DMM on the banded side of the diode, and the red lead on the non-banded side. A reading between .4 and .8 volts should be seen. If a reading outside this range is noted, remove one lead of the diode from the circuit and test again. If still getting a reading outside of this range, then the diode is probably bad.
Switch the leads of the DMM (red lead on the banded side of the diode), and a null or zero reading should be seen on the DMM. If getting a different reading, remove one end of the diode from the circuit board and test again. If a null reading is not seen, the diode is bad.
Are Diodes Polarized? The short answer is "yes", they are polarized. This means it does matter which lead of the DMM is connected the "banded" or "non-banded" side of a diode, as explained above. It also matters how the banded side of the diode is oriented when installed in the circuit.
Diode Values. Most general purpose diodes are rated at a peak voltage and number of amps, and are used as a blocking diode. This provides protection against repetitive reverse voltage (DC Blocking Voltage.) For example when a coil de-energizes, it tries to back flow power "up stream" to the driving circuit, sometimes in voltage twice the energizing voltage. To block this back flow of power, snubbing diodes are used.
Remember a higher amp and/or higher voltage diode can usually be substituted. For example, a 1N4001 diode is rated at 1 amp 50 volts. A 1N4004 diode, rated at 1 amp 400 volts, can be used in its place (the most commonly used diode in pinball is the 1N4004). Bridge Rectifiers (essentially four diodes in one package) are the same way (an increase in peak voltage and/or amps is OK). In pinball 1n4001 diodes are often used on 12 volt switch matrix switches, and 1n4004 diodes are used on 30 to 70 volt coils. But in either application, a 1n4004 diode will work fine.
Zener diodes can not be substituted as easily. These diodes are rated at a particular voltage and wattage. This voltage in nearly all circuits must be the same. Only the amp rating can be increased. For example, a 1N5237 zener diode is an 8.2 volt 1/2 amp Zener diode. A 1N4738 can work too, as it is 8.2 volts but at the a higher 1 watt power rating). And a 1N4196 (8.2 volt 10 amps) could be substituted because it still maintains the 8.2 volts, but at 10 amps. In most pinball applications 1/2 or 1 watt zener diodes are common (I personally always replace a 1/2 wat 1N52xx zener diode with a 1 watt 1N47xx version).
Zener Diodes, 1/2 versus 1 Watt Diode Voltage 1/2 Watt (1N52xx) 1 Watt (1N47xx) 2.4 1N5221 none 2.5 1N5222 none 2.7 1N5223 none 2.8 1N5224 none 3.0 1N5225 none 3.3 1N5226 1N4728 3.6 1N5227 1N4729 3.9 1N5228 1N4730 4.3 1N5229 1N4731 4.7 1N5230 1N4732 5.1 1N5231 1N4733 5.6 1N5232 1N4734 6.0 1N5233 none 6.2 1N5234 1N4735 6.8 1N5235 1N4736 7.5 1N5236 1N4737 8.2 1N5237 1N4738 8.7 1N5238 none 9.1 1N5239 1N4739 10 1N5239 1N4740 11 1N5241 1N4741 12 1N5242 1N4742 13 1N5243 1N4743 14 1N5244 none 15 1N5245 1N4744 16 1N5246 1N4745 17 1N5247 none 18 1N5248 1N4746 19 1N5249 none 20 1N5250 1N4747 22 1N5251 1N4748 24 1N5252 1N4749 25 1N5253 none 27 1N5254 1N4750 28 1N5255 none 30 1N5256 1N4751 33 1N5257 1N4752 36 1N5258 1N4753 39 1N5259 1N4754 43 1N5260 1N4755 47 1N5261 1N4756 51 1N5262 1N4757 56 1N5263 1N4758 60 1N5264 none 62 1N5265 1N4759 68 1N5266 1N4760 75 1N5267 1N4761 82 1N5268 1N4762 87 1N5269 none 91 1N5270 1N4763 100 1N5271 1N4764 110 1N5272 none 120 1N5273 none Diode Voltage 1/2 Watt (1N52xx) 1 Watt (1N47xx) Zener Diodes, 1/2 versus 1 Watt.
Testing Bridge Rectifiers. A bridge rectifier is essentially four diodes assembled inside a "black box". The bridge's job is to take AC voltage and rectify it to DC voltage. This is a very common component in pinball repair. Note testing a bridge is *not* conclusive to whether the bridge is bad! The bridge is being tested under NO load. Only a bridge which is shorted (and hence is blowing fuses) or open will test as "bad". A bridge could test as "good", and still not work properely. Also testing a bridge "in circuit" (while still soldered in the board) can often not give proper results.
Put the DMM on diode setting. Put the black lead of the DMM on the "+" (positive) terminal of the bridge. Put the red lead of the DMM on either AC bridge terminal. Between .4 and .6 volts should be seen. Switch the red DMM lead to the other AC bridge terminal, and again .4 to .6 volts should be seen. Put the red lead of the DMM on the "-" (negative) terminal of the bridge. Put the black lead of the DMM on either AC bridge terminal. Between .4 and .6 volts should be seen. Switch the black DMM lead to the other AC bridge terminal, and again .4 to .6 volts should be seen.
Transistors are essentially electronic switches. And TTL chips (Transistor to Transistor Logic), which are used extensively in pinball circuit boards, are basically a group of transistors packaged into a chip).
Testing Transistors. Testing transistors works much like testing diodes. Use the DMM's diode test. The individual electronic pinball repair guides cover all the transistor testing needed. See each repair guide for specific details. Some DMM's have a separate transistor tester. This works fine too, but requires the transistor be unsoldered from the board to use it (extremely inconvenient).
For the most part, the most common testing will be on "darlington" transistors (which means they are actually two transistors in one package) such as the TIP102, TIP122, TIP36 transistors. Also most testing is done "in circuit" (installed in the circuit board). For each of these have one lead of the DMM on the metal case (tab) of the transistor (which is usually the center leg of the transistor). Then the other lead of the DMM will test the outside two legs individually. A value of .4 to .6, or 1.0 to 1.2 should be seen, depending on the exact transistor, and which lead (red of black) is on the metal tab. The biggest indicator of a bad transistor would be a value less than .2 (probably a short). Look to the specific pinball repair guides for more exacting details of this. Also remember, a transistor can ocassionally test as "good", but in fact be bad.
Testing Chips. The DMM's diode test mode can also be used to check most logic chips. It's best to test chips out of circuit, but frankly this just isn't possible most of the time.
The LBT-10 (Lil' Bitty Tester) chip tester.
Another more advanced way to test chips is using a box called the LBT-10 made by Lil' Bitty Tester. Available from MCM Electronics (800-543-4330), these cost about $200. But in my opinion, it's worth every penny. If the chip in question can be removed from the circuit board without damage, the LBT-10 will test any TTL (Transistor to Transistor Logic) family of chip (7400 to 74xxx and their LS, S, HTC, etc. cousins). It also tests CMOS chips (40xx and 45xx series), which is *really* handy too! It works fast and is extremely easy and reliable to use. I *highly* recommend this product, especially for a newbie. The only disadvantage to this box is the chip needs to be removed from the circuit board to be tested, and of course the price. ABI in the United Kingdom makes a more advanced (and more expensive) version of the LBT-10 called the ChipMaster Compact. I am still looking into this product.
Chip Numbers. For the most part, if a circuit calls for a 74LS04, it should only be replaced with a 74LS04. But sometimes other chips can be used, as long as it is in the same "family". That is, logically these chips are all the same (a hex inverter), but their power or speed specifications may be different. But that is not saying that a circuit that used a 7404 originally will work with a 74HTC04. Often it will, but many times it will not. It just depends. For example, a timing circuit could react differently with a 7404 versus a 74LS04. More information on this can be found in the Short Course in Logic Chips above.
Capacitors store electrical charges for just a moment. These are used in pinball for filtering, making a rough signal or voltage more uniform and flat (the supplying voltage charges the capacitor, and as the voltage falls, the capacitor discharges, keeping the voltage at a certain level until the supplying voltage increases again).
Capacitor Values and Terminology. Capacitors are measured in some derivative of a Farad. For example, the caps in most pinball games are measured in "microfarads" (occasionally picofarads will be specified, but that is fairly rare). The proper way to designate 100 microfarad is "100uF" or "100 mfd". Here's a breakdown of capacitor terminology:
F : Farad. mF : millifarad, or one thousandth of a Farad. uF or mfd : microfarad, or one thousandth of a millifarad. nF : nanofarad, or one thousandth of a microfarad. pF : picofarad, or one thousandth of a nanofarad.
For a comparison, .039 microfarad (uF) is the same as .000039 millifarads (mF).
Another confusing thing about caps are how they are sometimes labels. For example, often ceramic capacitors will say "104" on them. Most caps will have three numbers, but sometimes there are just two numbers. These are read as Pico-Farads. An example, "47" printed on a small ceramic cap can be assumed to be 47 picofarad. If there are three numbers, it is somewhat similar to a resistor code. The first two numbers are the first and second significant digits, and the third is a multiplier code. Most of the time the last digit tells you how many zeros to write after the first two digits (in picofarads), but the standard has a couple of curves. To be complete here it is in a table:
3rd Digit Multiplier (this times the first 2 digits give the value in picofarads) 0 1 1 10 2 100 3 1,000 4 10,000 5 100,000 6 not used 7 not used 8 .01 9 .1.
Example: A cap marked "104" is 10 with 4 more zeros or 100,000 pF, which is otherwise referred to as a .1 microfarad cap. A cap marked "103" is 10 x 103 pF or .01 microfarad. Likewise "102" is 10 x 102 pF or .001 microfarad. Here's a table for ease:
Cap Value Cap Code .0001uF or 100pF 101 .001uF or 1000pF 102 .01uF or 10,000pF 103 .1uF or 100,000pF 104 1uF or 1,000,000pF 105 220pF 221 560pF 561 880pF 881 .02uF 203 .2uF 204 2uF 205 .022uF 223 .22uF 224 2.2uF 225 .047uF 473 .47uF 474 4.7uF 475.
In addition there can be a letter after the cap code. This tells the tolerance of the capacitor:
For example, a cap marked "33J" would be a 33 picofarad cap with +/- 5% tolerance.
Electrolytic Caps - Radial or Axial? Electrolytic capacitors come two different styles, radial or axial. Radial has both leads at one end of the cap, and the cap usually mounted vertically. Axial has the leads coming out of opposite ends of the cap, and these usually mount flat against the circuit board. Axial style are more common on the older games. I remember axial caps as having the leads on different ends by thinking of the earth, and how it rotates on its axis, with the axis sticking out of the earth at both north and Binary Options south poles, like the leads on an axial capacitor.
Testing a 1000 mfd electrolytic capacitor. The meter indicates 1128 mfd, meaning this cap is probably good. Note one lead of the cap is removed from the circuit board for the test.
If you are testing a 1000 mfd capacitor, it must test higher than that value to be considered "good". Anything lower than its stated value, and that capacitor should be replaced.
Of course the best way to test a capacitor is to just replace it with a new one! This isn't always cost or time effective, but it is really the best course of action if a capacitor is suspected as bad.
The Best Capacitor Tester - the ESR Meter. There is yet another way to test capacitors. Called the ESR (Equivalent Series Resistance) or low ohms meter, this is the best way to test caps. This nifty device allows testing capacitors in-circuit, with extreme reliability. This works especially good for repairing video game monitors and power supplies, but is also useful for pinball. Testing of all the caps on a circuit board can be done in seconds, without removing the caps.
The best deal on an ESR meter is the Dick Smith ERS, available at anatekcorp.com/testequipment/esr.htm. It's about $130 fully assembled. This is generally considered the best ESR meter, especially for the price. Also available is the Capacitor Wizard at about $200. Another assembled meter is the CapAnalyzer 88A, sold by MCM Electronics (800-543-4330), part number 72-6508, $179.
Are Capacitors Polarized? The short answer is "sometimes". Capacitors that are polarized will have some marking indicating the negative or positive lead. Capacitors that are not polarized, won't have any negative or positive markings. Often the negative lead is indicated with just a black line down the side of the capacitor. Also often one of the capacitor's leads (on a new cap) will be longer than the other (to signify polarity).
If testing an electrolytic capacitor (which has "polarity"; marked positive and negative leads), make sure to put the red lead of your DMM on the positive lead of the cap when testing.
Similar Capacitor Values. In most cases it is OK to increase the voltage a capacitor is rated. For example, if a 1 mfd 16 volt capacitor is specified, a 1 mfd 25 volt capacitor can be used. Usually it is not OK to change the Farad value of the capacitor, but small amounts can be changed. For example if a .49 mfd cap is specified, a .5 mfd cap can be used in it's place. Also never substitute a non-polarized capacitor in a circuit that is specifying a polarized cap.
Inductors or Chokes. Some Williams solidstate games use an inductor or choke, which is mearly wire wrapped aro