I have a DECstation 220 (Olivetti M250E) which is failing POST on a "simple test of the 80286 protected mode". It says in a service manual I have that for this test the CPU is set in the protected mode, the machine status word is checked to see whether it indicates the protected mode and then exits protected mode. This test seems to be failing. Is there any possible explanation for this other than a failed 80286 CPU? Could there be any external reason? This board suffered some battery leak damage. Clearly the 80286 is working well enough to execute this diagnostic and send some text to the screen, so it basically works.
Thanks Rob
