Cat 953c 2ZN2090 suddenly lost all gauges and alternator

It starts and moves, but no gauges or display when key is turned, or started. I deoxed the big connectors going to the black box (no corrosion noted), checked for ground continuity at ground strap of black box, checked all fuses, checked the two relays inside that fuse box (starter and master, I think).

I also checked the grounds in the instrument fold down access box (all good and clean). Key switch has expected output. I am scared to death it's that black box......please somebody tell...

Cat 953c 2ZN2090 suddenly lost all gauges and alternator