Certain lights out on Williams "Shuffle Inn" shuffle bowler

[stayouttadabunker]

Hi,
I recently picked up a 6-player 1989 shuffle bowler made by Williams.
The family really likes it!
Everything pretty much works great except for a few lights.
I checked and re-checked the bulbs and sockets till I was blue in the face...
But I'm not getting any power to them unless I close the + side of the sockets to the ground.

The player 1, player 3, and player 5 bulbs on the "column" aren't getting any power.
Should I be checking the "rows" instead?
These are wired from the Insert" board into a harness going to a "backplane" connector board behind the machine.
I checked for power at the backplane board output connectors to the Insert board.
No juice...

So I checked for power on that red/green wire on the main MPU board.
No juice there either....

Could it be a triac on the main MPU board?
There seems to be a burned component ( It looks like a small white rectangular block) on/around "Q62" and "Q64".
I'm thinking this controls the "column" of bulbs for the player #1/#3/ and #5 bulbs?

[tacman]

Stout, with my bad chaser light board on a topper it was one of those small white ceramic blocks, which is a fuse. This would make sense if it was blown. Hope this helps.

 Dan (tacman)

[stayouttadabunker]

I think you're right Tacman...
I didn't know what that little, ceramic block was...
sorta looks like a little tiny block of white cream cheese...lol...but if it's a fuse...it makes sense...
Looks like a little bit of brown smoky looking residue around it stuck to the board...
Smoke escaped I think!
Thanks a lot buddy, I'll try replacing it and see what happens.
If I jump the fuse for a few seconds, the lights should come on I think.
If they do, then I know the ceramic fuse is no good?

[tacman]

That's how I tested the topper, by jumping it first. Good Luck.

 Dan (tacman)

[channelmaniac]

That sounds more like a high wattage wirewound resistor and not a fuse.

I wouldn't short across it.

There will be writing on side of it. Can you post what it says?

RJ

[tacman]

I absolutely defer to channelmaniac on this, much more experience in the matter. 

 Dan (tacman)

[Flexpipe]

When I worked on earlier Bally Solid State Pinball games that had lamps out, I traced it back to the Lamp Driver board, and the associated lamp driver transistor. Just replaced the transistor, and I had the lamp again. Not saying this is simliar, just sharing a "similiar" experience that may be helpful.

[stayouttadabunker]

okay,
I jumped the little white cream cheese with a wire...blew out the transistor below it....lol
I should have read channelmaniacs post before I jumped it!....lol
More Smoke Lost!!!!  

I found out that the little white cream cheese block is a Resistor and not a fuse.
The number on it is: IRC 9025 PW5 27 ohms? (funny looking upside down "U", and it's NOT an "N") 2w C.F.

The little black thing (Transistor) that blew up when I jumped the resistor is : NPN, Darl. 2N 6427 TO-92 EBC

Gotta go shopping in chinatown for this stuff now...lol
The hard thing is I gotta wait about a month for this stuff to come in from Hong Kong Post....arghh!

I looked in the schematics of this CPU board...
in tiny little writing it specifically says that these 16 little white cream cheese
blocks need to be at least 1/4" raised away from the particle board...
well, upon closer examination, I found that the brown residue that's stuck to the board coming from the
Resistor is there because the little white cream cheese block in question - got crushed a bit
too close to the board during it's lifetime somehow.
With power turned off, I raised the Resistor slightly away to make proper clearance as per specs.
The things I'm learning though...lol...it's amazing.
The good thing is that the Williams Electronics Games technology is
somewhat similar to IGT S+ slot machine boards as both platforms were made during the same time.
Not all is lost though, in retrospect, once I get the proper components to repair this board,
I'll have a clue how to repair my dozen or so
crappy S+ 10 and 16 MHz boards that all have persistent "reel spinning" code problems!....lol