I received an API CS20 yesterday that I bought second-hand. It had a
bad power supply (red LED in standby mode and would not power up). I
replaced the power supply with a spare I had and it powered up, and
LEDs are now green. Unfortunately, I am not getting output from
either serial port (I expect to see "2048 Meg of system memory,
Initializing GCT/FRU", etc etc).

I have tried the recovery options documented in the user manual by
setting jumpers on the J2 jumper block (restore factory default
environment settings, upgrade/recover firmware, and failsafe reflash
from CD-ROM). None of these jumper settings appeared to do anything,
and I never saw any kind of output on my serial console.

I also swapped all RAM from a healthy CS20 I already had - the healthy
CS20 still boots fine, and no change on the "new" machine. There is
also no change if I power on the machine with no system RAM at all.
Nothing I've tried so far has produced a visible change in the power-
on sequence. At this point, I am not sure what is wrong and could use
some advice.

I am wondering if the flash memory containing the SRM has been
damaged, perhaps when the original power supply died. Does this seem
reasonable? I found the flash memory IC on the motherboard (an
AM29F040B-120JC), and it seems I could order a replacement IC
cheaply. Assuming this was the problem, I could then do a failsafe
reflash from CD-ROM. But I am just guessing here.

Any advice appreciated. Thanks in advance.