I’m not sure if this helps, but I dropped a Flippp PI-1/X4 into my System 1 and totally recommend it.

Give this a read: http://www.pinrepair.com/sys1

The info there is invaluable.

This looks familiar if I read your message right...

5F20C3AC-0DDD-4B11-8EA0-E193A2411B29 (resized).jpeg

I wouldn't automatically default to replacing the board if everything is pretty much working as is.

First I would try recharching the displays. Each display only needs a few seconds.

Second, check all the voltages for the displays and make sure there isn't something that is significantly low.

In certain instances, one malfunctioning display can affect all the other displays, so also be sure to test each display one at a time to see if you can figure out if there is one causing a problem. Note: only plug/unplug displays when the power to the game is off, or various chips will be destroyed.

I would take one display at a time and rotate them in the machine and out (power off each time) to see if the problem goes away on any one display. You could also replace R1 resistor (10k ohm, 1/2 Watt, 5% resistor) on each. Pinwiki has a voltage chart to check the UDN6118 chips. If all the displays do this individually and no change when you check each one individually then I would start looking at the board or connectors. Even with the new PS you should still use pinwiki and check voltages: "As stated above, the displays need several sources of voltage to function properly. The display voltages used are broken down by the type of display: +60VDC, +8VDC offset, and 5VAC are used for the 6-digit displays; +42VDC, +4VDC offset, +5VDC logic (for the 7432 chip - Z1), and 3VAC are used for the 4-digit status display. When using a 6 digit display with DI513 Dionics chips, +5VDC is necessary for RP1 and RP2 8.2K resistor networks. If any of the above voltages are missing, the display will never light. "

Did you clean the edge connector contacts with a pink rubber eraser? Grime on the PCB contacts will cause issues.

If you have a spare MPU, swapping that in might be able to tell you if it's an MPU issue or not.

If you haven't done so already, try replacing C16, C17, and C20--the three electrolytic caps on the left side of the MPU. I'm not sure if it will make a difference, but it's worth a shot.

Next, I might try replacing the electrolytic caps on the displays just to rule those out.

Then finally, look at the segment logic on the MPU. Check to make sure that the chips involved don't have cracked solder joints on the legs. Then, maybe try to figure out if there's a bad chip somewhere. If any have visible cracks or other physical damage to the chip's body, replace them.

Yeah, bright displays don't need to be recharged. Yours appear plenty bright, and shouldn't need recharging.

Since it looks like a thermal problem, wait for the game to warm up to working order.
Grab an ice cube from the freezer and put it in a thin watertight plastic bag, or even better use some electronic freeze spray if you've got it.
With the game working, switch it off. Hold the bagged ice cube against a chip on the MPU board for about 10 seconds. Power on.
Repeat the process moving from one chip to another until the problem hopefully re-occurs.
Start with the display controller chip at U6, then move to the supporting display logic chips after it (Z11 through to Z21).