https://pinside.com/pinball/forum/topic/vids-guide-to-bulletproofing-williams-system-6

viperrwk

GI coming up does not indicate the MPU is booting. The MPU and driver board could be missing all together and the GI would still light up.

Are the feature lamps active - i.e. does the game appear to be in attract mode? If not, do you have 5V and 12V on the MPU?

The connector in your hand is where power enters the board.

So to confirm - the game is booting and going into attract mode and you're also able to start a game, however there is no sound during gameplay? Have both displays and sound been non-functional the entire time you've had the game?

Sorry, misread your last post.

The LED flashes seem to indicate a properly booting board, though it's possible your batteries are dead (or holder corroded) causing the game to boot into audit mode. This, coupled with the fact your displays are out, would make it seem like your game is totally locked up.

I would recommend doing 2 things:
-open the coin door, turn the game on, wait a few seconds, then very quickly flick the power switch off/on. If the game goes into attract mode your batteries are not doing their job.
-check voltages at J5 on the power supply and make sure you have 5v, 100v, and -100v for the displays.

Just realized you have a Rottendog controller/displays so 100V / -100V are irrelevant in your game.

There shouldn't be -5V on any of the pinouts of the power supply. Are you sure you didn't reverse your DMM leads accidentally? Can you confirm you have 5V at TP9 on the MPU and 12V at TP1?

At this point, depending on how much experience you have, you may want to consider hiring a qualified repairperson to look at the game. There are a number of upgrades that need to be done to get system 3-7 running reliably (linked to by viperrwk above) and these should really be done before continuing to troubleshoot your problem as they may well be related.

Also, there is very little in the way of self diagnostics on the system 6 MPU and if you don't have the right tools and test ROMs these boards can be extremely difficult to diagnose.

I'd have to agree - you probably need to take the time to do the commonly suggested updates or have someone do them for you. In this case, I would probably replace the 40-pin connector between the MPU and Driver, reflow the 40-pin male connector on the MPU if you don't replace that. Remove any IDC connectors and replace with crimped Molex connectors. Reflow all the pins on all other connectors. Make sure the bridge rectifiers are fused. In short, take a look at Vid's Bulletproofing guide and do everything in it.

Other things to consider, though I don't think they would affect attract mode lights and such:

Does the game have the required number of pinballs installed? My BK, for example, will not start a game unless it can find 3 balls on the playfield.

Have you checked all your fuses, both for proper size and condition, using a meter? Don't count on a visual check.

Sound in attract mode may be a configurable option, so lack of attract sound may not be a problem.

Firepower does require 3 balls in the trough to start a game, but the OP's machine isn't even going into attract mode.

Replacing any and all Scanbe sockets on the MPU should be of equal importance to replacing the 40-pin connector. I'd also replace the masked flipper ROMs with EPROMs and convert the board to use a single 2732 game ROM to minimize the number of sockets replaced.

You'll also want to prioritize rebuilding the 12V / 5V chain on the power supply as the 5V is now under increased load with the LED displays.

It's normal in the sense that those connectors are always in pretty dismal shape. Definitely needs to be replaced!

There also appears to be some battery corrosion on a few of the pins:
40-pin.png

Any corrosion on the boards will need to be cleaned up and neutralized.

Check the CMOS 5101 chip, game won't boot if its faulty.

Yes. All bets are off until the female interconnect or are replaced. Do them all not just the ones that are missing. Carefully check the male pins too, in particular for cold solder joints.

Andy

I usually replace the male side too. The modern square pins sold by Great Plains Electronics will give you a much more reliable connection compared to the original round pins.

That looks like the warming resistor for the flash lamps. If you plan on installing LED flash lamps, just leave it burned as it needs to be removed for LEDs. If you want to replace it to keep the incandescent bulbs, it is a 330 ohm 2 watt stock but you should bump the wattage up to 3 watts or more so it won't burn up over time.

On the stuck sling, step 1 is to check the 2 sling switches on that side to ensure they are gapped about 1/16" when at rest with the machine off.

Toasted resistor is 330 ohm 2 watt, replace with 5 watt. If using LED flashers leave this resistor out.
For right kicker, pull connector 2J13 at top right of driver board. If coil does not lock on check the kicker trigger switches and the cap on those switches. If it still locks on then on driver board check Q10. If shorted, also replace Q9. If those are both OK, then IC9, IC7, IC5.

TIP122 is ok, TIP102 is preferred as it can handle more current. Hope you have been shutting game off immediately upon hearing any coil locking on. Time to check the diode on that locking coil as well as checking the coil for proper ohms. Must disconnect one end of the diode for proper test. If the coil checks less than 2.5 ohms, it is bad. Check q10 & q9 again, they may have gone. If coil & diode checks ok, replace q10 & q9 again. If it still locks on, I would suspect IC9.

Pull 2J13 on the driver board. If the coil does not lock on, then one of the switches behind the kicker rubber is stuck closed, diode on switch bad, or something's shorted between there and connector 2J13. If it still locks on, then pull IC7 and get a socket in there. Put the IC in the socket leaving pin 13 out. If the coil locks on, IC7 is bad. If the coil does not lock on, it's the PIA (IC5). You could leave it like that (pin 13 out) as the input from the PIA is only used during solenoid test and not required for normal game play.

Top left pop also? You must have posted that as I was writing my reply. Cut the blue/brown wire on that pop coil so we can tackle these one at a time. In my last post I meant to say capacitor on switch, not diode. Quick way to check is just cut one side of the capacitor and see if coil still locks on.

...

Special Sol.jpg

Top left pop - Q2, Q1, IC9, IC6, IC10

Congrats on the solenoid fix!

If the LED flashers are staying lit, the warming resistor may still be working even though it looks burned. Try separating the pieces of the warming resistors or clipping one leg if they are still solid.

Good job on the solenoids!

Now for the displays. I would look at the 9-pin connectors (1J5, 1J6, 1J7) at the top of the CPU board as well as the solder on the male pins on the board. These feed data to the master display board.

http://www.pinwiki.com/wiki/index.php?title=Williams_System_3_-_7#System_6_2

viperrwk

Visually inspect the master display board. There is resistors that burn (10k i think) use half watt or one watt resistors to replace).

The 9 pin headers across the top of the mpu are for the displays. Check them.

The jumpers eliminate troublesome data buffers. The two diodes and the resistor is for the special sized FP ROMs.

I doubt this would cause the interference and GFCI tripping but thought I would let you know that many Firepower games have the power cord incorrectly wired from the factory. The hot lead was wired to the fuses and the neutral is wired to the switch. It should be the other way around.

A GFCI trips when there is leakage of current from hot to ground. Finding the point of leakage may be like finding a needle in a haystack unless someone on here knows of a common failure point.

Off the top of my head, it could be the power filter or the transformer.

Might be worth checking that the hot lead is wired correctly first. Correct that and see if the problem continues.

The display signals leave the CPU board at 1J5, 1J6, 1J7 at the top of the board. Reflow the solder to the pins on those connectors to see if that helps with the missing digits and displays.

I can't tell by looking at that picture which is the hot on the incoming wire. The green is definitely ground and looks to be soldered to the tab on the EMI filter, which looks right. With the machine plugged in and your meter set to AC, one probe on the ground braid and the other on the fuse. If you get 120V reading, they are backwards.

BTW, I have my doubts that this is the cause of your problems with the GFCI.