Understanding DECsystem 5100 Self Test Failure

Robert Jarratt robert.jarratt at ntlworld.com
Mon Jan 5 13:20:38 CST 2015

> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Richard
> Loken
> Sent: 05 January 2015 18:37
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: RE: Understanding DECsystem 5100 Self Test Failure
> On Mon, 5 Jan 2015, Robert Jarratt wrote:
> > I have kept the original, but I am not sure that it was faulty in the
> > first place. I think the fault is something else, but I am not sure
> > what. I did find some pages on how to "repair" one, but I would rather
> > be sure it is faulty now before trying to do anything to it. For the
> > record the RTC self-test passes successfully.
> I agree that you might want reserve judgement on the RTC.
> The RTC problem in my Alphaserver a very strange (and well documented)
> case.
> If the battery is dead, which it is after 20 years on the job, then the
system time
> is not what OpenVMS expects so it refuses to boot.  I have not found a way
> around this except to reinstall VMS which I did on two occasions and then
it will
> run just fine (for VMS anyway) until the next time the power is
> That business gets old really fast - especially when the guy in the next
> trips the circuit breaker less than 24 hours after I have brought it back
on line.
> I like this big noisy box and I like VMS so I must fix the RTC.

Have you tried buying a DS12887 as a replacement? They are supposed to be
drop-in replacements, and if yours is already socketed then it should be
pretty simple to try.



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