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obitus1990

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I have a USA CPS2 board which was working fine, other than the fan was dead upon my purchasing it. I received my replacement fan today, and after verifying that it worked properly, I disassembled the A from the B board (with its darksoft kit) and installed the fan. After reassembling and connecting the supergun back up to it, I powered it on and the PicoPSU immediately switched off. I verified that I had the edge connector aligned properly (which I did) and tried again with the same result. I also checked the supergun on my NEOGEO MVS and it worked properly. I disassembled it all again and put a multimeter to the JAMMA edge connector and immediately found that the 5V line is shorted to ground. The reading was something like only 0.5 Ohms resistance between 5V and ground.

Are there any COMMON failure points on these boards that fail short?

I'm totally bummed because the fan was the very last part I needed to finish out the kit and play the games, now, unfortunately, none of it works.
 
What happens if you remove the fan?
 
Same thing. I failed to mention that I removed the fan after disassembly of the two boards and checking with the multimeter.
 
It doesn’t have a little k onscreen nearby saying .5. kohms right? Measuring on pins eg 1 and 3 when unplugged from the supergun? Just checking the easy stuff. Most common I’d think is the power pins out of alignment, which is why your jamma harness or supergun should have a Key in it. They’re cheap, can even be 3D printed, and prevent stuff like this from ever happening.
 
It doesn’t have a little k onscreen nearby saying .5. kohms right? Measuring on pins eg 1 and 3 when unplugged from the supergun? Just checking the easy stuff. Most common I’d think is the power pins out of alignment, which is why your jamma harness or supergun should have a Key in it. They’re cheap, can even be 3D printed, and prevent stuff like this from ever happening.
No, no kiloOhm designation. Yes, when unplugged, and, also, I am using a 3D printed key I made myself for this very reason. I fear it's something far more complicated than this.
 
Located the problem...the cap right next to the A --> B connector. The legs were too close together to begin with, I'm sure, and maybe somehow the cap got some compression from me disconnecting and reconnecting the the two boards.

Anyway, I desoldered this cap, straightened the legs out, soldered it flush with the board, and now the PicoPSU doesn't power down instantly. All that's left to do is reassemble everything and make sure it all still works (fingers crossed!).
 

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