You may want to post more prominently that the game is Road Kings (which is a Williams System 11.) I took the liberty of tagging your thread with the game.

I'm not well-versed in System 11 games, but I would say check transistors on the driver board.

I'm sure others can chime in who will be more helpful.

Tinabanana - the first thing you need to do is get a schematic of your game. Follow this link for a schematic.

http://www.ipdb.org/search.pl?any=road+kings&search=Search+Database&searchtype=quick#1970

This will allow you to determine which transistor controls which solenoids. Look on the very first page and you will see that there is a table that shows the solenoid and which transistor controls it along with wire colors, connector identification, etc. etc.

Once you identify the transistor you can use your DMM to test it. Also, you can clip a wire to the tab of the transistor and then ground that wire. This should fire the transistor activating the corresponding coil.

Give this a try. Let us know how it goes. You can be sure you will get lots of help here. I have now repaired/restored four machines with the help of my fellow pinsiders! I am about to get started on my 5th machine in a couple of weeks. You will enjoy repairing your machine and get a great sense of accomplishment when it works and you did the repairs.

Al

ISCSEMI-TIP102-pinout.jpg

Think of a transistor as a diode with three pins for testing purposes. On all transistors, the arrows on their data sheet will indicate that electricity should only flow in that direction, identical to a diode. With your meter in diode test mode, put the black probe on the base pin 1 (left) and the red probe on the emitter pin 3 (right). If you see zero resistance on the meter, the transistor has shorted. If that checks out okay, put the red probe on pin 2 (middle), and the black probe on pin 3 (right). Again, if you see zero resistance, it is shorted. You should see infinite resistance in both of those tests, just like a diode would if you try to go in the opposite direction.

That diagram may look a little confusing, to explain better, this particular transistor is called a Darlington pair. It is just two transistors sandwiched together in one little package.

Keep in mind those instructions are specific to testing TIP102/122/36 transistors. The pre-drivers and other transistors on your machine have a different pin-out, but the testing and information I gave you still applies.

The blue box thing is most likely a relay. Take a picture of the board and upload it so we can help you better.

To replace the transistor, you'll definitely want to remove the board. Once you've got it out, it's easier to test transistors anyhow.

I would check any associated resistors as well. (On later games, diodes are on this board as well and should also be tested, but they should be on the coils on Road Kings.)

What you are seeing there looks like there was PCB trace damage, so the person used the leg of the transistor to connect directly to that pre-driver transistor above it. Nothing really ghetto about that unless the underside of the board also has traces/connections that have been disconnected/neglected. Judging from the flux around that transistor though on the pads, it looks like a good candidate to replace anyway. I would test the pre-driver transistor that is just above it as well, these parts often fail together. When you desolder and replace that transistor, you can either bend the leg again and resolder it onto that trace, granted there are no traces on the opposite side of the board for that pin, or you can put the part through the original holes and run a jumper wire up to that pre-driver transistor. I prefer to run jumpers, but it is really personal preference.

The buzz is normal when lights turn on and off on all machines. It lessens when using LED bulbs as less current is being drawn.

Above each of those TIP102/122's is the pre-driver transistor. If both test out okay and aren't shorted, and you are reluctant to try and remove them, perhaps you can ask someone else to help that is nearby.

If I were dealing with this issue of yours, I'd first make absolutely sure that I have my coil wiring done properly. Then I would just go ahead and replace all 6 of the TIP102s along with their pre-drivers. Why? Because $4 worth of parts and 10 minutes of board work is easier and less expensive than dealing with $2 fuses blowing each time I turn the machine on while trying to guess which parts are bad.

Use Slo-Blo everywhere would be my guess. I haven't come across a pin that used anything else.
The Relay is soldered in place. It is the flipper enable relay, it is probably working fine so I'd leave it alone.

I agree with this, assuming you have decent board work skills.

Collin, nice collection. How do you like the Bad Cats? I've always wanted one.

Thanks! Some of my games are a bit rough; most of my more recent purchases have been projects to some degree.

Bad Cats is a lot of fun now that I've rebuilt the flippers. It definitely plays like an earlier game, without multiball or anything too complicated. It's a keeper for me because of the art... I would say the art package is an A+ and the gameplay is about a C.

Sounds good! For that sort of work, it helps to have a desoldering gun (I recommend a Hakko 808) but if he's skilled with a soldering iron, I'm sure he can get it taken care of.

An actual solder gun probably doesn't have a fine enough tip for this sort of work; I've been there, tried that, and personally wouldn't use a solder gun for anything on a circuit board other than maybe a reasonably large cap.

Get something with an adjustable temperature or minimum 25 watts, otherwise you'll end up with cold solder joints and lifted traces. After a year of using a crappy radioshack iron (15-watt), my dad-in-law gave me his Weller WES51 station and I realized soldering wasn't so hard after all. Flash forward a decade and hundreds of projects later, and I'm still using that equipment.

Best advice I can give - For small solder pads and components, if you have to hold the iron down on the pad/component for more than 3 seconds to melt the solder, it is too cold. If it melts instantly or smokes a lot, it is way too hot. An adjustable iron comes in handy when you're working on large components (like these transistors), jacks and switches that require substantially more heat to melt solder properly. Even with the added heat, larger components will take longer to melt solder onto (sometimes several seconds before it starts flowing). No worries for switches and jacks though, as you can't really damage anything with heat. Always apply heat to the pad/component first for a second or two, then melt solder onto it. The end result should be mirror shiny, not dull or grey looking. If it isn't shiny, it is too cold. Also, don't put solder on the tip then place it on the area unless you are tinning a wire. Good luck!

Tina, good advice from everyone. Just my $.02 worth get a good Hakko digital temperature controlled soldering iron like their FX-888D or FX-951. It will last forever in home use. Also, if you really get into repairing pinball machines you might want to get the Hakko 808 desolder tool that someone suggested. I have the Hakko 808 and one use (removing a forty pin display) made it worth its weight in gold. Got mine on Amazon but someone on Pinside was at one time offering them at a good discount. Don't know if that is still available.

A good way to practice and learn is to get some old junk PC boards and practice unsoldering components and then resolding them. You can probably get some from the electronic junk yard AKA electronic recycling center for free or check out a TV/Stereo repair shop.

It wont take long to develop the skill necessary to solder and desolder if you have good equipment. If you have cheap AKA poorly performing equipment it will make it a drag and you will not get good results and may even further damage something.

Let us know how things go with your Road Kings.

That is correct for coils with a single diode, but it does matter for coils with two diodes.

Can you manually push the bumper coil up and down with it out getting stuck? If you can't, you may need to replace the coils & sleeves for them. They should move freely with no friction.

I'd go to the schematics at this point. Both switches and coils are wired in a matrix. They go in chains and overlap each other. Switch matrix issues won't cause fuses to blow, but coil matrix issue could. You may have a bad diode in another area on the same line as the bumpers that is causing them to stay on. I don't know for sure because I didn't check, but it is likely both pop coils are on the same row or column of the matrix. Inspect the diodes on the other coils/test them in diode mode on a meter.

I had an issue somewhat similar to this on my JackBot. The issues were intermittent, and really frustrating to deal with. A friend taught me what I would call a last-resort method for diagnosing these issues:

First, disconnect the power wire from each coil that's powered through the fuse that keeps blowing. (make sure you protect exposed wire with electrical tape, and label which wire goes to which coil.) Power the game on and see if the fuse still blows; if it does, you've probably got a break in a wire somewhere that's allowing it to short out against something else. Assuming it doesn't blow go through this process: Power off, reconnect one coil. Power the game on and see if it blows. If it doesn't, power off, and reconnect another. Repeat until you've gone through this will all coils. You may well have multiples that're problematic.

It's a bit laborious, but it's how I finally diagnosed a problem that drove me mad for months.