Some amount of DG goodness

Jay West jwest at
Mon Sep 21 09:01:03 CDT 2015

I decided to raid the front panel of my S/200 to get a switch cover and a
switch for the S/130; what can I say - I got antsy to see if the S/130
worked ;) When taking the S/200 front panel apart I found it really wasn't
in great shape as it had appeared to be from the outside. A large number of
the incandescents had broken off and were sitting loose and one of the
switch covers was broken so someday I'll return to the S/200 but the S/130
restoration was completed as a result. 

Pictures (completely out of order) are at but the first picture shows the
cpu up.

Once or twice, running the microcoded self-test produced a "Rom Error", but
almost always it produces the desired result and loops on that test (checks
microcode checksum, ability to execute and step microcode, a few CPU
instructions & paths, and tests the lowest 16Kw of ram). Raising switch 0
halts cpu at microcode address 2 just as it should.

I also noticed that on rare occasion, hitting "examine" on AC1 produces no
result - but other than that I can store and read AC0-3 as well as several
different sections of memory. 

Next step is to locate a 4045 board and see if I can get a console hooked
up. After that, I'll need some way to get diagnostics into the machine. To
that end, I could try restoring a HD, 8" diskette, paper tape, or dual
cassette drive - but I'm wondering if there is any previous art for entering
a front panel ditty and stuffing diags down the console port (from a PC)?
Yes, google is my next stop ;)

Thanks to several listmembers and especially Bruce for pointers and advice,
as documentation is scarce and not organized the way my brain works. 



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