My White Water started resetting. Pin 1 on the CPU ROM was only showing 4.55V. How it was working at all I have no idea. I reseated the 5v/12v logic power connectors going between the power driver board and CPU board and cleaned up any tarnish or dirt on the header pins. I'm now seeing 5.00v at the 5v test point of the power driver board and 4.98v at the 5v header pin of the CPU board and the positive side of C31. That's great, but the CPU ROM is still showing only 4.75v. The game is stable now, but why am I still getting 230mv of drop locally on the CPU board itself? Replace C31? It's original.

This is the pin in the upper right of U6. I read this was the best way to get a "true" 5v reading. I may have the wrong pin though, is there another pin on U6 for VCC (logic power)?

I revisited this today. I was indeed checking pin 1 when I should have been checking pin 32. The voltage coming in to the CPU board is 4.93v, and so is VCC power for the CPU ROM on pin 32. However, I think my issue is elsewhere. First of all, I noticed the left flipper pulses the high power winding 3 or 4 times every time I hold it up. I'll need to test the EOS switches. If it's not that, which I'm sure it is, I also noticed there are some bypassed resistors on my CPU board. At first I thought there was some corrosion and broken traces, but there is no battery corrosion at all. I also checked the IC the wires connect to, and it's the same part as another CPU board I have.

Now I'd like to know why someone did this and if it may be causing occasional resets.
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Is that the one of the chips for the switch matrix that goes up in smoke if there's a high voltage to switch short on the playfield?

I swapped the CPU board as a factor and after confirming it's 100% I installed a remote battery holder. I think have the correct solder connections but the board is not holding memory. The voltage from the battery pack with 3 new batteries is 4.52v. Maybe the there's open diode?
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I figured out I was soldering to the wrong tabs. Memory is good now and the original question is resolved. Thanks.

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