I would try a very slow oscillator like 10mhz

I wonder if you have a blown chip, hard to test without a stack of spare 286 systems

Deksor wrote on 2020-09-07, 12:55:

I have added it to UH19 here...

Thank you 😀

rmay635703 wrote on 2020-09-07, 15:31:

I would try a very slow oscillator like 10mhz
I wonder if you have a blown chip, hard to test without a stack of spare 286 systems

Slowest I have in my parts box is 24MHz, tested with it but nothing changed. I surely have slower ones, down to 1.something MHz, but I'll have to temporarily desolder them from other working boards. I have a stack of spare 286 motherboards but no complete systems.
All 'glue' chips tested OK on the TL866, so I guess that leaves the possibility of (1) me overlooking something when I repaired the corrosion, (2) some broken trace or via in any part of the mobo or (3) a fried chipset (contrary to rumors, static damage does happen. Many times I receive the boards wrapped in plain bubble wrap which sometimes is so charged that I unwrap it under water, especially when it's a rare board).

I do not know everything but have never seen a XT or 286 with DIP ram work when BANK0 is not fully populated. There is no way 4 dip ram plus 2 parity will work on any board I know of. You need to populate BANK o all sockets, usually 16 of them plus the parity. I cannot find the manual but do know what you have for ram is wrong for a DIP memory based board no matter how you set the DIP switches, you do not have the proper memory chip setup.