[HN Gopher] HP 5036A Microprocessor Lab
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HP 5036A Microprocessor Lab
Author : peter_d_sherman
Score : 41 points
Date : 2022-03-17 17:43 UTC (5 hours ago)
(HTM) web link (azurelectronics.com)
(TXT) w3m dump (azurelectronics.com)
| peter_d_sherman wrote:
| Related:
|
| https://www.hpmemoryproject.org/wb_pages/wall_b_page_12.htm
| retrac wrote:
| Fun tangential fact. HP was then one of the main manufacturers of
| microprocessors. At the time (early 1980s) they had either in
| prototyping or manufacture at least three distinct lines of
| microprocessors; none of which they offered to the public, only
| for sale as part of a product.
|
| The Nanoprocessor, [1] [2] which was a very fast and simple 8-bit
| microcontroller used in a variety of test equipment. The HP
| Focus, [3] a full 32-bit processor design used in their HP 9000
| series. And the Capricorn, [4] a small BCD-oriented processor
| used in their calculators. By the mid-80s the first PA-RISC
| designs and HP Saturn would be out, too. Those were also only
| used inside HP devices, never sold directly for other users.
|
| [1] https://www.righto.com/2020/09/inside-hp-nanoprocessor-
| high-...
|
| [2] https://www.cpushack.com/2020/08/09/the-forgotten-ones-hp-
| na...
|
| [3] https://en.wikipedia.org/wiki/HP_FOCUS
|
| [4] https://en.wikipedia.org/wiki/Capricorn_(microprocessor)
| jll29 wrote:
| I still miss my HP 9000/715 (+735 at work), those PA-RISK CPUs
| and HP-UX were typical HP design excellence (and bleeding
| fast).
| zwieback wrote:
| The fab in Corvallis, OR, where a lot of the custom hp circuits
| were made later turned into a wafer fab for inkjet printheads.
| Still going on to this day although much smaller than before.
| atdrummond wrote:
| My grandfather, while a flight surgeon, learned about
| microprocessors on this beauty in I want to say 1983 or 1984. He
| later purchased one for us grandchildren and spent the 1980s and
| 1990s showing us how to program these devices. Most of us hated
| it but I fell in love - it definitely tracks that I was the only
| member of the third generation to go into tech (or at least
| directly).
|
| Does anyone know of a firm that repairs these or a guide to
| fixing them one's self? Our's bit the dust a few years back and I
| have an inkling what's wrong but I don't want to accidentally
| make the situation more desperate by charging in blind.
| unwind wrote:
| Send it to Ben Heck, or any of the several other electronics
| YouTubers. Check interest/rate (if applicable) first, of
| course.
|
| Good luck!
| Luc wrote:
| These are very simple computers. You could probably diagnose
| the problem with a multimeter and a logic probe (or
| oscilloscope). You'd check the supply voltages, then check the
| clock on the CPU, check the reset pin etc. But very often the
| problem is a capacitor that has gone bad, e.g. on the power
| supply.
|
| Have a look at arcade game repair guides. This one seems
| decent: https://forums.arcade-museum.com/threads/how-to-fix-
| pcbs-a-b...
|
| Make sure socketed ICs are properly seated.
|
| Good luck!
| atdrummond wrote:
| I've checked the ICs in the past and there weren't any
| socketing issues but I haven't had a chance to take a deeper
| look at the board since then. I'll give it a more honest
| college try based on your encouragement.
| mlyle wrote:
| I built a "modern" version of something like this for middle
| school students.
|
| https://github.com/mlyle/armtrainer
| peter_d_sherman wrote:
| Looks really good!
| cbm-vic-20 wrote:
| This is great! I think people think that kids need some cutesy
| or dumbed-down GUI environment to teach computer fundamentals,
| but this shows kids how computers really work at a low level.
| jhallenworld wrote:
| The LED display driver is interesting in this device. It uses
| 75492 (still available!) for the digit driver and DS8871 for the
| segment driver. Except DS8871 is open collector, so it is used to
| force a segment off. For on, there 100 ohm pull ups. These are
| just the drivers, the latches are separate.
|
| This is a circuit you want to optimize to reduce cost...
|
| For comparison, here is a Z-80 "membership card". It uses 74LS145
| for the decoder/digit driver (driven from a counter) and 74HC273
| for latch+segment driver.
|
| http://www.sunrise-ev.com/photos/z80/zmc-manual.pdf
|
| The famous KIM-1 uses discrete transistors:
|
| http://www.zimmers.net/anonftp/pub/cbm/schematics/kim-1/kim....
|
| A really modern device might use an integrated LED driver, like
| TM1637 or TM1638:
|
| https://www.amazon.com/dp/B01D140BT6/ref=sspa_dk_detail_0?ps...
| indymike wrote:
| Remember having to write programs on this, or something very
| similar it while training in the US Navy in the early 90s. For
| most of the others in my class, it was the first thing they ever
| had to program - and we started with machine language (and ended
| there, too).
| bdavis___ wrote:
| USAF Tech School, about 1984. Fantastic hands on labs. Also
| showed the use of the "current tracer", which was real cool.
| But I have never used one since. There was a wand that would
| sense current, and there was a device that you could touch to a
| PCB trace and it would inject a signal. With the current
| tracer, you could see the current disappear when it was shorted
| to ground by a bad PCB trace.
| anonymousiam wrote:
| "Signature analysis" was a thing that HP tried to push as a
| test/troubleshooting tool, but I've not seen much mention of it
| anywhere for the past 20+ years.
|
| https://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1977-05.pdf
| ddingus wrote:
| [ Deleted, lame question I reconsidered. Happens.]
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