Well I'm hoping for the memory section that I can find at least one of the 4 core boards that works right away. I've got an 8k driver board I can swap it so I could run the system on only a single core board if needed. I'd probably write a short program to do a bunch of memory writes, reads, and such to exercise it for a few hours or such.
The power supply going bang is one of my worries. I've got an old 80s logic analyzer with power supply issues, while testing got a big spark by one of the huge filter caps in it and it put me off working on it for a long while XD. It would have been quite nice if there was no CTuL logic in the system, when repairing my Altair if I find a dead logic chip I can still buy modern compatible replacements. If one of these die, I'd probably have to build a circuit out of discrete transistors on an ugly protoboard. On Tue, Aug 2, 2016 at 3:46 PM, Rik Bos <hp-...@xs4all.nl> wrote: > > > > -----Oorspronkelijk bericht----- > > Van: cctalk [mailto:cctalk-boun...@classiccmp.org] Namens Jay West > > Verzonden: dinsdag 2 augustus 2016 23:24 > > Aan: 'General Discussion: On-Topic and Off-Topic Posts' > > Onderwerp: RE: HP 2100A Restoration > > > > > > There is an HP book specifically on I/O interfacing to the 2100 (and > 21MX) I/O > > bus. I think there's also an abbreviated chapter on it in a different > manual. I'll see > > if I can dig up the name and if it's online anywhere. > > > > I've restored at least five 2100's, and run a dual cpu 2100A & 2100S > system > > regularly. I have never heard of nor seen a power supply failure on any > of them. > > The power supply always came up with little or no pot adjustment, and > nothing > > else required. I'd be surprised if your PS needed any attention unless > they were > > under water. > > > > Debugging the memory section is a far different matter. It's far *far* > easier to > > troubleshoot if you have a known working set. If not, it's very easy for > boards to > > test ok and then later fail and then later test ok (bad upper section of > a 16K > > driver, etc.). > > > > J > > About power supply failures mine did have one, when under power after a > few minutes there was a loud bang and the system resets. > Which would be repeated every few minutes, some investigating and > measurement later I discovered one of the high voltage elco's shorted every > few minutes. > Which started the power on cycle and resets the cpu. > After replacing those all voltages were stable and in range and the > banging was over ;) > > After some testing I concluded there were some faults in the cpu, being > the lucky owner of an extender board I was able to fix all the errors. > The HP 2100 service manual and hardware course and engineering reference > are a big help fixing the 2100 and as J says a set of known good cards can > be of help too. > But knowledge of the working of the micro instructions is also a big help, > IRC the micro instructions are described in both the engineering reference > and the service manual both can be found on bitsavers. > > The only weak point of the 2100 is the use of uCTL a Fiarchild DTL > derivate used for IO drivers in the 2100 series. > Brent Hilpert has a lot of info on his site about those gates. > > -Rik > >
