I believe I've been having voltage problems in my Raven. I was getting lights either stuck on or off & it started getting stuck on doing one thing (can't remember exactly what). I checked the voltages in the back of A1J1 & they were up & down. I shut it off & turned the pot on the PS back & forth a bit in case of a dead spot, turned it back on, set the voltage to 5.07vdc & it worked fine for a couple weeks.
Then the same lights started acting up again & the sound got too loud so I checked the voltage again & it was at 5.47v, so I turned it down. Worked for a bit, then started acting up again. I probed around & checked voltages in A1J1, the back of A2J2, & the SB. Made sure it was in the general vicinity, but it still wavers. The stuck lights still don't work & the sound gets too loud. I had to shut it off last night because of the sound.
I don't know where to look. Could the LM338 be the culprit? The pot had been replaced when I first got the game. Maybe this one's gone bad too? Any where I can clip the meter leads to watch if the voltage is fluctuating?
Second problem - while I was checking voltages, the scores & memory blanked. Now it doesn't hold any settings or high score. What did I fry?
And I wish I'd quit typing 'teh' instead of 'the'.

I had re-pinned A2J1 & one pin wasn't quite inserted correctly. I've corrected that, but there are still lights stuck either on or off. I'll see if the volume stays at one level instead of jumping up & down.
I guess the Up/Down Memory Protect Logic is what I need to look at for the memory problem? I'll have to read up @terryb's guide about testing various electronic components.

The machine now plays fine & the sound stayed the same volume last night, but lamps 28 thru 35 either stay on or don't turn on at all, so I think there's still a voltage problem. I'll take a closer look on the weekend, along with the memory problem.
Another problem was that the right coin chute stopped working. I found a wire had been disconnected. It's one of those connectors where the tab pushes into the female part. I didn't pull it off & it takes some force to pull off, so it didn't fall off. The GF's grandkids were her at Xmas, but it worked after that.

Burial Ground (resized).jpg

Hi Chris. It was replaced when I got it, but I'm thinking this one's gone too.
As for the memory, I checked the batteries & they were dead, about 0.3v. I replaced them with new batteries, each measuring 1.6v. The voltage at the pack connector is only 3.3v though. Is it possible I fried the diode? The memory & scores got erased while I was probing voltages.

There's a local electronic repair shop that I've used before. I'll bring the PS in next Monday, so I'll have it for the weekend. I also have the connectors so I'll have them replace those as well.
And the memory's back working again.

I got my PS back from the shop. The pot points upwards making it hard to adjust though. I had to plug in J1, check voltage at J2, remove the PS, adjust the voltage, plug in J1, check J2... Took a while but I got 5.05v at A1J1. Is that within reason?
Still have stuck on lights & sometimes holding the rt flipper button cycles through the lane change.
When I started having the voltage problem, I got voltages at A1J1 jumping from 3.5v to 8.3v, so I suppose the Z8 & Z9 on the driver board could have been damaged. I'll check them over the weekend.
As for the lane changing, I'm not sure what would cause that. I'll check the switch gap, but I doubt that's it. I tried tracing the wiring path in the manual, but I don't have a clue to where it goes.
Other than that, it appears to be playing fine. I'll have to play some more to be sure.

Finally looking at this again.
I adjusted the 5v & have a steady 5.03v across C1 on the driver board.
Still have L28 thru L35 stuck on/off. They go through Z8 & Z9.
More disconcerting is that holding the right flipper lane change usually causes the lane change to cycle & slows or stops the flashing lights for the two banks of standups. I also think it stops targets registering.
I have no idea where to start diagnosing this one. Any help would be appreciated.

Since it's summer, I've been in the garage "theatre" & haven't played this in while.
It's still got problems. I get a steady 5.05v across C1 on the MPU, but there are still lights stuck on/off, the sound gets really loud & holding the rt flipper button slows the lights for the two 3-bank standups (L41-L46).
I'm not good at diagnosis, so near as I can figure, looking at the switch matrix, it's A1J6, Z11, Z13 or U4. A1J6 has been re-pinned, so it's probably not that. I'll check Z11 & Z13, but I think I'll be sending the boards out. I was reading up to 8v at A1J1, so maybe a cap or diode got blown out.
I'll see if there's someone reasonably local.

Would the aux. power supply have anything to do with it? I'll have to check it out.