CPS1 makes popping sound, then nothing.

ReWrite

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Plugged in my Ghouls n Ghosts, the speakers make a loud pop sound, kinda like if you plug in computer speakers while they're on, then nothing happens at all. Worked a few months ago, it's been stored in a desk drawer all by itself in a anti-static bag, can't imagine what's happened to it :/.
 
Check your voltage on the harness, should be around 5.3V unloaded.
If that checks out check the voltage on a few chips.
Try reseating and cleaning the board layers.

Test the game with another A board if you have one.
 
Check your voltage on the harness, should be around 5.3V unloaded.
If that checks out check the voltage on a few chips.
Try reseating and cleaning the board layers.

Test the game with another A board if you have one.

No other A board, but I'll dig out the multimeter (not sure where I've put it) and try that much out. Thanks!
 
Okay, it had been at 4.8 under load, turned it up, still no luck. Going to reseat the boards now, any advice on which chips, or for that matter, which pins on which chips to test?
 
Made some mistakes, read a bit, learned how to test properly on the chips, and I'm getting 1.8v on the 27C4096's, every other chip is getting 5.2x.

Outside of knowing that these aren't getting enough power, I don't know what this means or where to go from here.
 
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Assuming you've measured it correctly, 5.2x is too high. I can't understand why the roms would be getting such a low voltage on the Vcc pin, see if you can follow the circuit backwards and find out what's dragging it down.
 
Assuming you've measured it correctly, 5.2x is too high. I can't understand why the roms would be getting such a low voltage on the Vcc pin, see if you can follow the circuit backwards and find out what's dragging it down.

I thought 5.2x seemed high since the data sheets say +-5%, but I was going off of above info saying it should be at 5.3V.

Seems I hadn't been doing it properly last time either... Vss is ground, I assumed it was G.

New readings are still WAY low at 3.89V

http://www.datasheetcatalog.com/datasheets_pdf/2/7/C/4/27C4096.shtml

Using that Datasheet. Vcc and Vss.
 
Managed to find pinouts for only one of the 4 A-B board connectors, so I've managed to check one and everything's A-okay. Trying to find pinouts for the other 3, but having a rough time.

CN1 and CN4 pinouts, still looking for CN2 and CN3 to make sure the B board's getting all its proper power.
 
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Well, now I get to sound more foolish. I misread the roms and had been testing a couple wrong, found datasheets for the right types of roms and EVERY rom reads between 4.99V and 5.02V, so now I don't know where to go at all.
 
At this point, according to the "How to Fix PCB's" section, I'd need a logic probe to move forward, right? Just looking for confirmation before I order one.
 
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