-Do you have 28V or so at the right side coils ? Check pinwiki for best test procedure.
-If not is there a broken wire between one of the coils or EOS switches or bad fuse (I don't have a system 6 right now so don't remember the fuses)
-When you push the right cabinet switch do you get continuity from any right flipper coil lug to the plug at 2J2-1 or 2J2-2 (flipper ground returns)
-If not figure out where the wire is broken. Test flipper to cabinet switch and cabinet switch to 2J2-1 or 2J2-2 (one is for left, one is for right don't remember).

Pretty simple circuit from memory.
-Turn game on and the flipper coil should have power. Check that.
-Start game and the relay engages to connect 2J2-1 and 2J2-2 to solenoid ground on the driver board. So if left flipper works, this should work.
-Press flipper button and flipper ground lug on the coil should connect to 2J2-1 or 2J2-2 and therefore solenoid ground. causing the flipper to fire

Note that the EOS switch is involved so check that is working correctly.

I Haven't worked on a System 7 display problems for probably 10 years so hoping for some help

I have had a Barracora for a few years that worked great until recently the player 2 and player 4 displays don't come on at startup. If I play an hour or so they might come on also but not always.

The ball credit display does the same but with the middle 2 digits out at first starting to come on after a while.

Looking at the schematics I cant tell what these all have in common except display 2 and 4 both are strobe 10-16. But the credits/ball in play are strobe 1 and 9.

So far I have:

Moved displays around and problem stays with player 2 and 4
Thinking it could be strobes I swapped the CPU with my backup and the problem is still there so its either connectors or the master display
For +90 and -100, I have +58V and -66V at the pins to the glass on both working and non-working displays.

If I dont get a place to start from this post, I will repin the connectors to the CPU, anyone know where to get replacement edge connectors for the master display. I was hoping they would be like traditional connectors but of course not.

Any help appreciated. Pic of current issue showing player 2 and 4 as well as the missing digits on the credit/match display attached. NOTE the master display is missing R15 so I understand why the commas are out on 3 and 4.

IMG_9634 (resized).PNG

This solved it Thanks!

I had tested the high voltage on the power supply with the connectors attached (at the resistors right before 3J5) but this post made me think it could be a connector. So I removed 3J5 and tested and again had +99.8 and -100. But when I put the connector back on all the displays worked.

Even though 2 displays worked fine, the low voltage made the others flaky. I was sure it was not a supply problem but a connector problem it was both. Its replaced and all good.