MVS 1FZ - Calendar Error & Diagbios CRC Error

One of my 1FZ boards came up with a calendar error, stuck on green. Iv'e changed the RTC crystal (the legs on the old one broke off) with a spare, after that stuck on green is gone, but now it says CALENDAR ERROR. I've already changed the 4990 IC with a spare, didn't do much. The signal on TP is there and the connections from 4990 to the Neo F0 are all there.

What else should I check?

The other strange thing is that when I change the bios to smkdan's NeoDiagBios, it comes up with BIOS CRC Error ... but the Eprom is verified and ok. The board also wrangles sometimes on screen text in weird ways, see picture.

I hope somebody helps you, because I have a board with the same problem, Bios CRC Error...I posted it in neodiag threath without lucky.

Did you already try something to fix it?

Yes, I replaced Neo-C1, Bios, Cpu, Work ram and F0, and I didnt continue because all time was the same error.

This board was working fine, and now blocks at boot, no bad traces or similar.

It's neither D0 nor E0. Still getting Calendar Error with stock Bios and CRC Error with NeoDiag.

Calendar error is D4990 broken most times. My mvs doesnt show calendar error, only blocks.

I have read you changed it...

The crystal for the D4990 was faulty, I've replaced it, Calendar Error still remained, replaced D4990, checked all inputs and outputs -> no change. I somehow think both faults are related.