CDS Big Cheese- no more button lights

[MarkInAz]

Randy  I did that, but didn't quite fry the board. I was installing a new light bulb in one of the buttons using a pair of needle nose pliers the bulb glass broke, shorted out the board and never ever got any of the button lights to work again, but the game still worked.

Hi guys,
Funny I should find this (above) from your old thread-
My neighbor's Big Cheese now has the same problem.  We are trying to figure out what happened after we changed a few bulls, then a few days later we noticed that none of them are on.  All the bulbs are good but no illumination.  We do measure a strange pulsing voltage on all the sockets but darn if I can make sense of it.  Buzz, did you have any luck with yours?

Mark 

[KirkLasVegas]

Randy  I did that, but didn't quite fry the board. I was installing a new light bulb in one of the buttons using a pair of needle nose pliers the bulb glass broke, shorted out the board and never ever got any of the button lights to work again, but the game still worked.

Hi guys,
Funny I should find this (above) from your old thread-
My neighbor's Big Cheese now has the same problem.  We are trying to figure out what happened after we changed a few bulls, then a few days later we noticed that none of them are on.  All the bulbs are good but no illumination.  We do measure a strange pulsing voltage on all the sockets but darn if I can make sense of it.  Buzz, did you have any luck with yours?

Mark 

The "Strange" pulsing you see is the matrix driving the lights. They are usually addressed in a X/Y matrix.
Typically you will see a set of NPN transistors as the source and another set as the return. Look for discolored devices in a group (Transistors).
Other machines have a completely separate source for lighting, if something kills the lamps the rest of the machine continues to function. CHECK POWER SUPPLIES FIRST!
Also look for diodes in the door wiring, sometimes they are under heatshrink in series with a cable bundle in the door.If you popped one of these it can kill ALL the lamps in the door.

"Needle-Nose" pliers are a disaster! dont do it! I use a piece of rubber vacuum line slipped over the end of the bulb. Create a vacuum on the hose and the bulb pulls right out from the top!


Kirk

[MarkInAz]

Thanks Kirk,

That's exactly what I'm thinking.  I could swap my Pickpocket mainboard with my neighbors Big Cheese but I'm pretty sure the problem is on his board. 
I've got a copy of the CDS US320 schematics and I do see the lamp common supply line "Lamp D0" from Q-16.  Funny though, I cant seem to find where the "LampV" voltage originates, its not noted on the mainboard or backplane drawing.  Wish I had the power supply schematics for the CDS US320 machine.  Guess I'll have to trace it back - Blah!   

[MarkInAz]

Success !  

Finally found out why all the door button lights, BV, & tower lights would not come on even though the rest of the game played fine.  Turns out that "LampV" voltage was originating on the Main circuit board but resistor R-6 was bad blocking the LampV path to all the lamp matrix switching FETs.  Replaced the resistor and tadah.  Luckely we looked around first & found a short on one of the BV bulb wire before we plugged in the repaired main board. The replacement was a pain because it's so small and ESD zapping is a big concern during the surgery too.  Be warned.

Cheers,
Mark

PS- I've got a few extra resistors if someone finds they need one.

[KirkLasVegas]

Success !   

Finally found out why all the door button lights, BV, & tower lights would not come on even though the rest of the game played fine.  Turns out that "LampV" voltage was originating on the Main circuit board but resistor R-6 was bad blocking the LampV path to all the lamp matrix switching FETs.  Replaced the resistor and tadah.  Luckely we looked around first & found a short on one of the BV bulb wire before we plugged in the repaired main board. The replacement was a pain because it's so small and ESD zapping is a big concern during the surgery too.  Be warned.

Cheers,
Mark

PS- I've got a few extra resistors if someone finds they need one.

Ya did good!
Was the bad one cracked down the middle?
0.1 Ohm resistors make good delay fuses

Kirk

[Foster]

Glad you got it working!

[icu44444]

hi mark.
hey if you still have some of those resistors, i would like to get them if they dont cost much. i have a couple of boards with similar issue and never have time to find n buy these little devices that will have you in reading glasses faster than old age.
 icu44444

[MarkInAz]

hi mark.
hey if you still have some of those resistors, i would like to get them if they dont cost much. i have a couple of boards with similar issue and never have time to find n buy these little devices that will have you in reading glasses faster than old age.
 icu44444

Sure,

Send me a SASE & I'll drop a few in for you.

Mark

[icu44444]

mark
thanks on the r6 info. even though the resistor looked(using magnifiying glasses looking into another magnifier) visually ok,  i found a pattern of resistance readings on the three of the boards different at r6 causing other components values to be different.  one other board had a different resistance  than the other boards also but the odd reading was at resistor r2.  out of 10 boards i selected the three that had the same pattern of values different than the rest at r6 I went ahead and replaced r6 with the ones you sent me and now those three having working lite matrix now. so KKKK's your way and to others who provided info in this thread and for sending me those resistors
icu44444

[MarkInAz]

All right, glad to hear that.  Funny how that little 0.1 ohm resistor can go bad with just a brief short on a lamp socket.  The bad ones I replaced changed from 0.1 up to about 500 ohms as I recall.

Cheers,

Mark