Understanding DECsystem 5100 Self Test Failure

Cory Smelosky b4 at gewt.net
Sun Jan 4 14:03:45 CST 2015

On Sun, 4 Jan 2015, Robert Jarratt wrote:

> When I power up my DECsystem 5100 I get the output shown at the end of this
> email. I thought this was to do with the DS1287 chip as it seems be an NVRAM
> battery error (perhaps). Since I know these devices fail I took out the
> DS1287, put in a socket and then bought a replacement DS12887A. But I still
> get the same problem. It could be that I bought a bad replacement, or that I
> have done some damage in my desoldering of the original, or it could be that
> the error is something completely different. In fact the Maintenance Manual
> suggests test 9 is to do with the DZ, and I can't find what test 4 relates
> to.

How does the DDS12887A compare in speed/timing compared to the original 
DS1287 I know with Suns some 150ns ones don't work, yet 100ns or 200ns or 
whatever are fine.

Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects

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