Nice work Mike! It's nice to have working machines for displaying at the museum! :-D <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon> Virus-free. www.avast.com <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Sun, Jun 11, 2017 at 10:46 PM, Mike Loewen via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
I worked on two projects at the museum, this weekend: my recently acquired Eagle IIE micro and the museum's HP 2117F display system. The Eagle is a 4MHZ Z80 system (CP/M) with 64KB RAM and SS 5-1/4" drives. The display was out of adjustment, with a "doubled" presentation. A quick tweak by Ian on one of the video pots fixed that, and I resoldered the leads to the reset switch which had been inexplicably cut by a former owner. Nice bright and clear display (green CRT), passes internal diags.
The HP 2117F is a circa 1983 mini, with a hardware floating point processor module. I pulled the power supply and checked the inside of the top cover for the infamous black form: yep. It hadn't quite started to disintegrate, but it was just a matter of time. I removed the foam and glued a plastic shield in its place. The power supply voltages were close, but I adjusted them to spec.
The system wasn't completing its self-test, and didn't seem to be recognizing its RAM. It turned out to be a missing ribbon cable which is supposed to connect the RAM boards (3 boards of 256KW each) to the controller board. I pulled a donor cable from our ugly 2113E hangar queen and the memory tests now pass. I also replaced 3 broken plastic toggles on the front panel with parts from the 2113E. I showed Evan how to toggle in a short program from the front panel to make the lights dance, Cylon style. To paraphrase a line from the movie, "Firefox": you MUST think in octal. :-)
The 2117F is missing a couple of crucial controller cards to connect to the peripherals in the cabinet: the HP-IB interface for the hard disc, the 7970B tape drive interface, and the interface for the 13037C disc controller. Fortunately, the 2113E has the requisite HP-IB card (12821A) so it may be possible to check out the HP-IB drive in the future.
Mike Loewen mloewen@cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/
-- ======================================================== Jeff Brace ========================================================