AlphaStation 200 NVRAM Problem

[Robert Jarratt]

> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Maciej W.
> Rozycki
> Sent: 23 April 2016 18:57
> To: General Discussion: On-Topic and Off-Topic Posts
> <cctalk at classiccmp.org>
> Subject: RE: AlphaStation 200 NVRAM Problem
> 
> On Sat, 23 Apr 2016, Robert Jarratt wrote:
> 
> > Well! I took out the DROM and switched it on again. The machine
> > bleeped at me, but then it gave me a console and I was able to boot VMS!
> 
>  I'm glad that it worked, this will certainly make further diagnostics
easier, and
> you have a usable machine anyway.
> 
> > I will have to see if the NVRAM is now populated and whether it will
> > continue to work with the DROM installed.
> 
>  First: to double-check, how did you know it was a NVRAM failure, did LEDs
> show DC (xxox xxoo)?

Yes that is exactly the code I get on the LEDs.

> 
>  Second: it may also be that DROM itself is faulty, a bit may have flipped
for
> example; NB this is UV EPROM, so things happen.  Maybe someone can
> share a known-good image.
> 

When I put the DROM back the failure returned. So it is either a bad SRAM, a
short/open somewhere, or the DROM code itself. I have a PROM programmer, but
it is only for DIP packages, I don't have the facilities to read a PROM in
this type of package. I will have another look round for any obvious
problems on the board, but it looked OK to me when I checked. Getting the
SROM diags out might help too, I will have a look at that.

Regards

Rob