Shorted Mortal Kombat 2 with multimeter

msdstc

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As the title says. I was working on my Mortal Kombat 2 after installing some new chips. Everything was working except the audio board was acting up. I went to check the voltages at the pins on the audio board. I must've shorted something because as soon as the probe touched the whole thing just shut down. I have a suzohapp switching power supply. The power supply turns on for a second when I try to turn the machine on then turns off. Sometimes the powersupply will come on and I'll just hear a light buzzing noise of some sort. The monitor powers on fine with neck glow and whatnot, but nothing on either the mk2 pcb or the audio board.
 
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why were you measuring voltage at the sound board? let's start there

I popped open the power supply to see if maybe something fried in there and found some old ass leaking caps and some general corrosion so that explains the wonky power supply stuff, ordered a new one from suzohapp. Any tips on what to check for on the board before the new one arrives?
 
for everyone reading this: +12V and -5V are not adjustable voltages. in a switching mode power supply they will never be exactly 12.00V or -5.00V. if you have no amplifier, you probably have no +12V. on a DCS sound game like Mortal Kombat II, if the sound just sounds like EEEEEEEEEEEEEEEEEEEEE!! you probably have no -5V. that's it. you don't have to prod around testing these voltages.

as to what to do, nothing. install the new power supply and if it works, it works. if it doesn't, then you can seek help. it sounds like your old power supply was on its way out anyway.

Randy Fromm logic: garbage in, garbage out. if you use old worn out power supplies, expect your game to not work well.
 
for everyone reading this: +12V and -5V are not adjustable voltages. in a switching mode power supply they will never be exactly 12.00V or -5.00V. if you have no amplifier, you probably have no +12V. on a DCS sound game like Mortal Kombat II, if the sound just sounds like EEEEEEEEEEEEEEEEEEEEE!! you probably have no -5V. that's it. you don't have to prod around testing these voltages.

as to what to do, nothing. install the new power supply and if it works, it works. if it doesn't, then you can seek help. it sounds like your old power supply was on its way out anyway.

Randy Fromm logic: garbage in, garbage out. if you use old worn out power supplies, expect your game to not work well.

Alright thanks yeah that's my approach for now. Just hoping I didn't short something on the PCB itself
 
Change those caps, i had to do 5 boards all same results. If you're not good at soldering, or solder iron doesnt get hot enough you will struggle. Goodluck
 

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As the title says. I was working on my Mortal Kombat 2 after installing some new chips. Everything was working except the audio board was acting up. I went to check the voltages at the pins on the audio board. I must've shorted something because as soon as the probe touched the whole thing just shut down. I have a suzohapp switching power supply. The power supply turns on for a second when I try to turn the machine on then turns off. Sometimes the powersupply will come on and I'll just hear a light buzzing noise of some sort. The monitor powers on fine with neck glow and whatnot, but nothing on either the mk2 pcb or the audio board.

Maybe @zenomorp's video can help.


He also has other sound board repairs.

 
After testing the power supply I'll look into the caps. I already recapped the soundboard among a bunch of other things, but was still getting weird issues. Are there any caps on the game board that are inline with the audio board that could affect it?
 
Maybe @zenomorp's video can help.


He also has other sound board repairs.


These videos are an invaluable resource, I love stuff like this. He has so many that I actually somehow missed that this particular video is almost identical to what happened to me. Thanks a ton!
 
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