4.85 is too low. You need 4.95 or higher.. preferably higher.

Look at your transformer secondary voltage connector, the one on the transformer that brings the voltage up to the driver board.

Look at J101, the input voltage connector. This guy can sometimes burn.

I would definitely look at J114 and J210, if you're getting a .2 drop between CPU and driver, even if you had rock solid 5.0 on the driver board, the drop would still likely lead to resets on the CPU board. You should only see a very negligible amount of drop from driver to CPU.. maybe .02 or .03 - not .2.

Look at C4. Look at C5. Look at the LM323.

The game should be resetting at .85, honestly. You need to either fix your power driver board, or get a new one. Don't forget BR1, and BR2. BR1 is less likely to be the bad componant, as it's not directly involved, but I've seen it drain the 5v before.

The +5 comes on the rectangular one, not the cube one.

Yes, I'd say the 4.65 is too low and is causing the reset.

The LM323 can be involved here. I just had one that was good at initial powerup, like 5.01, but after running for a 6 hour burn in test, it dropped to 4.91. J101 was tarnished, so I replaced it. Pulled C4 and C5, tested them with my cap tester, out of spec, replaced them with new parts that I tested first and were OK, fired it up, and my initial 5.01 had dropped to... 4.88!

Replaced the LM323 and now, it's good. Comes up at 5.01, and after a 4 hour burn in, still at 5.01. I'm content with that. Gonna let it go another 2 hours on the burn-in and check voltages again. This one is going on route, so it's important that it's rock solid.

From my experience, a bridge is good or bad - no such thing as marginal. It's just 4 diodes. Either it tests good, or it tests bad.

On your game, here's what I'd do

1) Replace the female plug that connects to J101 and retest voltages
2) If voltages are off, verify traces to/from J101, BR2, LM323, C4 and C5. Don't pull parts, just put your meter on continuity test, bust out your schematic, and verify everything is connected where it should be. Maybe reflow the solder points on them.
3) Test again. If still no bueno, inspect C4 and C5. Are they bulging at the ends? I've found that caps are RARELY the problem, and you stand a pretty good chance at damaging plated through holes swapping them out.

Unfortunately, there's no good way to test C4 or C5 without removing them. They don't test real well in circuit. So, even if you had a cap tester, you might not be able to get a good test on them in-circuit. So, if you're going to pull them to test them.. I typically replace them. But, I do a LOT of testing before I remove them.

One way to avoid that is to clip the leads (if they're axial) and solder the new cap onto the existing leads with little pigtails. I don't even bother with guessing about caps if they're more than 15 years old, I just replace them.

Guilty of that myself but I like to solder and do board work....

As much as I like nice test equipment and a Cap tester would be sweet that same loot pays for a lot of bridges and caps. I like nothing more than replacing factory original components. They are not hacked up and once replaced should last another 15 or 20 years.

And in most cases you need to remove the cap from circuit to test it. Do what defog says, just replace electrolytic caps when you have any suspect of the circuit.