[rescue] Did i nuke my SS20?

[Romain Dolbeau]

Le lun. 2 aoC;t 2021 C  15:37, Ray Brooks <ray.userinterface at gmail.com> a
C)crit :
> Can anyone offer any advice as to next steps, or to help me
> identify the issue?

Having just replaced a NVRAM chip in a SS20 (using a MT48T08-100PC1
brand new from Mouser), the first POST can take a lot longer than
expected.

Suggestion:

a) remove all DRAM but the one in the first slot, to minimize memory checks
b) only keep the module in MBus slot 0 (bottom), to minimize mbus checks
c) keep an eye on your keyboard leds

When you power-up, all 4 LEDs should blink once, then the caps-lock
one should start blinking to indicate POST.
After a while (shortened by a) and b) above), the screen should sync
and give you access to the PROM. Beware some screen will need nudging
to detect the signal if there was none at power-up (my Iiyama 17" CRT
defaults to the VGA port rather than the BNCs where the SS20 is, so I
have to force the switch from VGA to BNC if the signal doesn't come up
fast enough on the BNCs).
All the details on the LEDs are available (and which slot/port is
which) in the service manual 801-6189-12 (Which Oracle still has
online, they are not all bad:
<https://docs.oracle.com/cd/E19127-01/sparc20.ws/801-6189-12/801-6189-12.pdf>
)

If there's no blink at all (not even the power-up one), you may have
troubles (or the keyboard is dead/undetected).

If there's the initial all-blink but no follow-up on the caps-lock
led, then there's a POST issue. Double-check the seating of the DIMM
and MBus boards, and of the NVRAM chip; the NVRAM can easily be
inserted off-by-one-pin!

If the system reaches the caps-lock blink, then the final pattern will
indicate an error if there' s one, IIRC; but you should get some form
of display eventually.

Cordially & good luck,

--
Romain Dolbeau