HP 2100A Restoration

Lyle, I didn't know you had such a collection of 2100's and 21MX and E's and F's! I need to come and visit! Marc

> On Aug 1, 2016, at 7:12 PM, Lyle Bickley <lbickley at bickleywest.com> > wrote: > > Hi Hayden, > > On Mon, 1 Aug 2016 19:29:05 -0600 > Hayden Kroepfl <perlpowers at gmail.com> wrote: > > --snip-- > >> With regards to the power supply, I'm thinking my best bet would be >> to do a power on with no cards in the system. Though I'm not sure >> if all the power rails would even come up without a load on it, >> since it sounds like it may do some power sequencing from what >> I've read. I was wondering if anyone has some experience with >> testing a similar power supply that hasn't been run in at least 10 >> years? > > Those of us who have brought up HP2100s that have been stored (even > in military packaging) know the power supplies can be a "bear". The > PS is a "fold out" deal - and never used to be repaired in the > field by FEs. They were swapped with new units - and the failing > supply sent back to HP for refurbishing. The process was detailed > to me by a person who sold 2100's as an OEM for many years. > > That being said, they are a early design switching supply - and > should have a load when powering them on. > >> I'm not sure if using a variac to slowly warm up the supply and the >> caps would be wise on one of these power supplies. I'm not sure how >> the switching supplies would handle the low voltage at the start. > > I would definitely NOT use a variac on them. It's best to check the > caps (and reform if necessary) and then power it up with a load. > You may have to "gently" (as in slowly) turn the PS on and off a > number of times to work out the years of "dormancy" (reforming the > capacitors that you can't get to ;) > >> The only I/O card that was installed in both machines, besides a >> terminator board in only one of them, is a serial interface made by >> some company with the logo CMC. It uses a COM2502 UART which I was >> surprised to find a datasheet for, however I haven't found any >> information on the card itself. I have a photo of the card in the >> album linked below if anyone has any information on it. > > The 2100 has a weird I/O addressing scheme - so check the manual > carefully. Moving a card from one location to another in the > mainframe changes its address! That's very different from DEC (and > many others) who had switches or jumpers on boards to change > addresses. interrupts, etc. > >> I know this email is getting a bit long, but with regards to the >> memory both machines have a ID(16K) driver board, and two core >> modules. However one machine has both core modules marked >> 02100-60052 on the bridge, and the other has one marked >> 02100-60052 and the other 02100-60054. Is there any difference >> between these modules? I'd assume by the 16K driver in both, that >> all of the core modules are 8KW modules. Would that just be a >> later revision or is one a different size? > > Look on bitsavers: http://bitsavers.trailing-edge.com/pdf/hp/21xx/ > and start reading manuals (particularly the Maintenance and > Drawings). There a wealth of information to be found there - and > it's what I used to get my 2100S running. > > --snip-- > >> I'd very much appreciate any help or suggestions that peopleh ave. >> I really want to get at least one of these machines back into full >> working order to have some fun programming with. > > HP2100 restoration is very doable. > > And the 2100 has one of the best front panels going :) > Like how can you not like buttons that light up when you push them!? > > Most of my problems with my 2100S were related to the power supply - > and a few related to memory. > > Wishing you the best!!! > > Cheers, > Lyle > -- > 73 AF6WS > Bickley Consulting West Inc. > http://bickleywest.com > > "Black holes are where God is dividing by zero"