It's generally bad when a PCB catches on fire, right? DK up in flames.
So, I've been repairing a DK JR cocktail which had a bad board and a bad monitor. I shipped the board off for repair and did a cap kit on the monitor tonight. I buttoned it all back together, adjusted the B+ to 108vdc, set the brightness, width etc so I had a pretty good solid white picture... everything on the monitor seems to be OK as far as I can test.
So, I decided to take my working DK PCB and pop it in to see how the monitor looks. My DK Upright does not use the edge connector, and there was a "rainbow" cable (mine actually has all yellow wire but it's the same thing) connecting the two PCBs. The cocktail uses the edge connector. I metered the voltage coming from the edge connector (which is keyed so it can only go on the proper way) and everything checked out... +5v, +12v and -5v within tolerance.
I then slid the PCB into the cocktail, leaving the metal mounting brackets on the board which are normally used to mount the board in my upright (I fear this may have been the cause of the fire), popped on the edge connector, made sure the board wasn't touching anything (the metal of the board was touching the metal of the cocktail table but that's it.. it wasn't touching the monitor or any wires) and flipped on the power. I heard a POP and saw a lovely little fireworks show. :\
R13 and R33 burned up, and the transistor at Q3 popped. There's no other visible damage but I suppose other things downstream could be fried.
What did I do wrong? I'm guessing either the metal cage, or I should've removed the yellow cable connecting the two boards. Any ideas on how to proceed?
EDIT: I just downloaded the schematics to see if I can figure out where those resistors are fed from, and wow is that greek to me.. Can anyone more knowledgeable take a look?
Double EDIT: From Mike's Arcade repair logs
I am 99% sure I hooked up the sound amp properly (the connectors are keyed, and the wires are short enough that I don't think I could've mixed up JB and JC), but on the off chance I did hook these up wrong, would it explain what happened?
TRIPLE EDIT: GODDAMMIT that's exactly what I did. I swapped around JB and JC. Anything to do other than to replace the resistors and transistor and fire it up, hoping for the best?
So, I've been repairing a DK JR cocktail which had a bad board and a bad monitor. I shipped the board off for repair and did a cap kit on the monitor tonight. I buttoned it all back together, adjusted the B+ to 108vdc, set the brightness, width etc so I had a pretty good solid white picture... everything on the monitor seems to be OK as far as I can test.
So, I decided to take my working DK PCB and pop it in to see how the monitor looks. My DK Upright does not use the edge connector, and there was a "rainbow" cable (mine actually has all yellow wire but it's the same thing) connecting the two PCBs. The cocktail uses the edge connector. I metered the voltage coming from the edge connector (which is keyed so it can only go on the proper way) and everything checked out... +5v, +12v and -5v within tolerance.
I then slid the PCB into the cocktail, leaving the metal mounting brackets on the board which are normally used to mount the board in my upright (I fear this may have been the cause of the fire), popped on the edge connector, made sure the board wasn't touching anything (the metal of the board was touching the metal of the cocktail table but that's it.. it wasn't touching the monitor or any wires) and flipped on the power. I heard a POP and saw a lovely little fireworks show. :\
R13 and R33 burned up, and the transistor at Q3 popped. There's no other visible damage but I suppose other things downstream could be fried.
What did I do wrong? I'm guessing either the metal cage, or I should've removed the yellow cable connecting the two boards. Any ideas on how to proceed?
EDIT: I just downloaded the schematics to see if I can figure out where those resistors are fed from, and wow is that greek to me.. Can anyone more knowledgeable take a look?
Double EDIT: From Mike's Arcade repair logs
Mike's Arcade said:Problem: All sounds are present, but very low volume.
This board took a hit from the monitor sound amp being hooked up backwards 1. The large 3 pin connectors were put on incorrectly. When the game was powered on, the board smoked about 5 parts, R1, R38, R28, R29, C12 and Q1. The most of them actually flamed and all were toasted. Also the traces under R29 and R29 were burned, as well as the pads that R1 were soldered to were destroyed. After fixing all those parts, the sound was still faint.
Solution: R1, R38, R28, R29, C12 and Q1 and repaired many toasted traces
I am 99% sure I hooked up the sound amp properly (the connectors are keyed, and the wires are short enough that I don't think I could've mixed up JB and JC), but on the off chance I did hook these up wrong, would it explain what happened?
TRIPLE EDIT: GODDAMMIT that's exactly what I did. I swapped around JB and JC. Anything to do other than to replace the resistors and transistor and fire it up, hoping for the best?
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