It's generally bad when a PCB catches on fire, right? DK up in flames.

hindered

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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

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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You'd be surprised how many people get JC and JB swapped. I would double check you connectors, they should be labeled. But I think you just shot a bunch of ac voltage on your board.

Good news is for the right amount of $$$ it can be fixed. Just not by me.
 
I would double check you connectors, they should be labeled. But I think you just shot a bunch of ac voltage on your board.

Yes, they are labeled, which makes this stupid mistake even stupider.

I put the board back into my DK upright, and the game boots up and plays as expected, although there's no sound (to be expected) and the game seems to play a little bit fast. I'm hopeful that replacing the resistors and transistor will get the board back up to snuff.

However, I put the board back in the cocktail (after switching JB and JC back the right way) and the game seems to boot (I get hum like I get in the upright) but I get nothing to the monitor... monitor stays a flickery white screen. Is this something to take up in the monitor forum?
 
It has been a while since I worked on DK boards, but from what I remember you can get a video signal from either the edge connector or a connector on the board. You may try both outputs before working on your monitor.....

By the way, I too remember a similar 'fireworks show' when I was building a DK cabinet a few years ago...... :)

Note: dickmillikan is a SUPER great resource for any and all questions......
 
Been there, Done that! Besides the smoke, there was an actual flame coming out of the board. Toasty.

Yeah, I had a 2-3 inch flame as well. Hopefully I won't need to jumper too many traces.

Rampart35 said:
...but from what I remember you can get a video signal from either the edge connector or a connector on the board. You may try both outputs before working on your monitor.....

Thanks for the tip. Can I power the board from the edge connector and run the video off the board connector?
 
FWIW I got my monitor running and tuned in today. Needs to degauss but that's not a big deal. Just waiting for my transistors to show up and I'll replace the components and see if I can get sound back.
 
Edge Pinout

Here is the edge connector detail for a two board version....

On the parts side: 16-Gnd, 17-Green, 18-sync,
Solder side: T-Gnd, U-Red, V-Blue
 
Here is the edge connector detail for a two board version....

On the parts side: 16-Gnd, 17-Green, 18-sync,
Solder side: T-Gnd, U-Red, V-Blue

Yeah, I got that from the manual, thanks. I don't know why the monitor wasn't originally working, must've been a bad connection somewhere. Works well now after lots of dial-fiddling although the red is a bit saturated and I don't feel like pulling the monitor out of the cocktail again to get access to the neckboard.
 
Replaced burned 150ohm and 1kohm resistors, and shattered 2sc1815. Put boards back together, put PCB back in upright, fired it up.. heard the telltale jump booting sound and smiled. Popped in a credit, full sound is back. Everything sounds great. Glad I got off with a ~30 cent repair. :)

BTW I ordered the transistors from electronix.com and can't recommend them more highly. Their prices are reasonable, min order is only $5, shipping was super reasonable, they called me the day after I ordered to let me know a part was back ordered and made sure I got my parts on time. Great site, great communication, would do business with again in a heartbeat. I had my parts in my hand 2 days after my order. Not bad!
 
Looks like I spoke too soon. After playing for a while, board freaks out. Mario warps to the top of the screen... no fire in the oil barrel on the girder stage, so barrels come super fast and always take the first ladder available.. board freezing and displaying garbage etc.. Guess I need to do more investigation.
 
Looks like I spoke too soon. After playing for a while, board freaks out. Mario warps to the top of the screen... no fire in the oil barrel on the girder stage, so barrels come super fast and always take the first ladder available.. board freezing and displaying garbage etc.. Guess I need to do more investigation.

So, I got around to putting the board back into my cocktail table and the gameplay is asymptomatic... seems to run 100% as expected. This leads me to believe that the issue was with my upright cabinet, so I got out the multimeter and tested the voltages coming out of the power supply... ~+5.2vdc ~-5.2vdc ~+12.18vdc coming out of the supply. I'm assuming this is too high for the board and causing the freak outs.

It's got an original Nintendo power supply, and I don't see any way to tweak the voltage via a potentiometer. How do you adjust these? Do I need to rebuild it? I'd prefer to not replace it with a switcher if at all possible.
 
The adjustment for the voltage is inside the ps and you have to take it apart to get to it.

Sounds fun. I should probably test the voltage coming out of the cocktail and see what it's putting out.

The other difference is the cocktail uses the edge connector and the upright uses the individual connectors, so I guess something could be messed up with the individual connectors, or possibly the voltage runs through different components/paths depending on which connectors you use...

edit:tested voltage coming out of cocktail.. it's a touch lower but more or less the same... +5.18vdc.
 
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So, I got around to putting the board back into my cocktail table and the gameplay is asymptomatic... seems to run 100% as expected. This leads me to believe that the issue was with my upright cabinet, so I got out the multimeter and tested the voltages coming out of the power supply... ~+5.2vdc ~-5.2vdc ~+12.18vdc coming out of the supply. I'm assuming this is too high for the board and causing the freak outs.

It's got an original Nintendo power supply, and I don't see any way to tweak the voltage via a potentiometer. How do you adjust these? Do I need to rebuild it? I'd prefer to not replace it with a switcher if at all possible.

Those voltages are fine. The question is.....are those voltages making it to the motherboard?

Edward
 
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