Hi all, First post about my first Pin.

I have been systemattically doing mods to this machine to improve its reliability. So far I have done:

CPU:

5V indicator
Battery Removal, extremely minimal leakage on the back side of the board.
Ground Improvement

Driver Board:

5V indicator
Ground Mod(Pending)

Pop Bumper Boards: (Already updated boards)

5V indicator
Replaced the large cap on the boards

Power Board:

All fuses replaced
Capacitor Replacement(Pending, doesn't have orange Cap)

Now for my questions/issues:

The PBDB does not light up on either board, but the pop bumpers do pop when I Short the can transistor. The pop bumpers do not activate when the spoonswitch is toggled. Would this indicate a bad MPS-A13 on the PBDB or do I need to also add the "Fire" LED as well?

The Photo LED board (detects the presence of balls in the drain) does not power on, but is recieving power.

The game boots fully and can get into play/test modes, however no score occurs when switches are closed and no balls are kicked into the lane (probably due to the photo LED failure). The music also does not play, but I do get a sound as though the machine has been tilted upon pushing the play button. The game will not let more than one player on, either. If the machine is tilted it does not recover and continues to display TILT on the screen(probably related to the photo LED failure again).

Prior to desoldering the battery, I would get sound on bootup. Subsequent power cycles could foce the music to play, however, since desoldering the battery I am no longer getting sound out of the machine when I power cycle it (a good sign I hope). When I run the switch test, it indicates all switches are closed now. Do I need to close the circuit for the battery with a diode or will a simple wire do the trick? I have no intention of putting a battery pack into the machine.

###The DROM1 on the sound board is fried and I cannot find a resource to get one from the net, does anyone out there have an EPROM burner that supports 27C256s? (Found one, Ignore this line

Bootup displays All 00000000s in the four player areas, which I believe is normal function as indicated via PinMAME booting the rom. The game is a normally OPEN slam tilt switch, also.

I appreciate any help anyone can offer!

I will probably end up adding one into the machine. My reason for not replacing it immediately is I don't care about high scores or replay values.

Right. So do I need to actually close that circuit or not, since it just powers the RAM while the machine itself is powered off?

The tilt-bob is open, as is the playfield tilt. There is no ball tilt switch that I can locate.

The switch test indicates all switches closed. Prior to removing the battery this was not the case, all switches were shown to be open and could be tested individually in test mode.

Providing an update here.

Working over the contacts on the CPU board has caused the PBD boards to recieve full power and function.

Tracing over the diagrams for the Driver and CPU boards has led me to believe a cap has gone bad causing the L0 to L11 to be inoperable.

A failed capacitor could cause that whole circuit to fail, right? Or could it be one of the four diodes that feed into the IC?. I have yet to test these with a volt meter. That is on my to do list for tomorrow.

I will do that then. Does anyone have a suggestion on where to get the edge connector pins for repinning the rest of the single sided cables? My local stores don't carry then or the crimpers anymore.

Running through some electrical tests I found out that the potentiometer was only putting out 2.5VDC when turned up to the maximum. I will be replacing the component and retest.

I am updating this for anyone that cares and for my own reference.

The pot on the power supply board. The problem has been resolved for that board.

I am still running into all switches closed with everything unplugged but the display and cpu board. Theres probably a short somewhere as pressing the start game button triggers test mode, which is not normal operation.

Also, still having issues with L0 to L11 not lighting. That may just be a connector issue, which I can't do anything about until my new connectors arrive.

edit: If anyone out there has this machine, could you get a picture of the front and back of your CPU board? Thanks.

L0-L12 ended up being a connector issue.

The Z11 chip is burned out and thats the chip which controls switches (I am 95% positive).

I still have to repin all of the connectors but I am stoked to get this far with no starting knowledge.

Turns out the Z3 chip was cracked on the bottom side causing part of the logic to not function.

All thats left to resolve is the issue with the controlled switches (Spot targets). I believe these are controlled by the Z14, which also makes the same cracking noise when light pressure is applied.