PDP-11/05 microcode dump?

Mattis Lind mattislind at gmail.com
Mon May 9 13:23:17 CDT 2016

2016-05-09 19:42 GMT+02:00 Eric Smith <spacewar at gmail.com>:

> On Mon, May 9, 2016 at 5:13 AM, Mattis Lind <mattislind at gmail.com> wrote:
> > Last time I had a PROM failure is what the internal address decoding that
> > failed which was easily seen as certain patterns repeated all the time
> Not impossible, but it seems more likely that one of the address input
> pad buffers failed.

You're probably right in that. On the other hand looking back on what I
wrote I see that I wasn't completely accurate in describing the symptom...
The symptom was that the upper 128 words was inclusive-OR:ed with the lower
128 words resulting in a quite strange upper 128 words. That was my reason
for suspecting the faulty address decoder.

Anyhow I have now ordered a bunch of Texas TBP24SA010 chips which I hope
the old Data I/O 29B will be able to program successfully.

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