HP 2100A Restoration

[Lyle Bickley]

On Tue, 2 Aug 2016 21:44:48 -0700
Curious Marc <curiousmarc3 at gmail.com> wrote:

> 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

I have way too much of a lot of stuff ;)

Lyle

> > 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"  



-- 
73      AF6WS
Bickley Consulting West Inc.
http://bickleywest.com

"Black holes are where God is dividing by zero"