Vintage Computers

I picked up a HP2100A at a pawn shop this week. 1971 system that introduced a lot of new concepts including the "microprocessor" (implemented with discreet chips across two cards), microcode (you could add instructions be adding or reprogramming ROMs) and a switching PSU that brought the weight down to 50KG. :)

Memory is still Core, this one's got 2 x 8KB Core cards.

Unfortunately some of the gold-plated ROM chips got badly corroded so I'm busy finding replacements. Everything else seems pristine.
 

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They're 256 byte ROMs and I'm not sure about the levels and supply. So you might need to build an adaptor board.

But, I believe, one can still find the chips on eBay. And I found the ROM dumps and someone who can program them.

Would like to keep it as original as possible.

Incredibly, I found someone in Cape Town with a working model.
 
jannievanzyl said:
I picked up a HP2100A at a pawn shop this week. 1971 system that introduced a lot of new concepts including the "microprocessor" (implemented with discreet chips across two cards), microcode (you could add instructions be adding or reprogramming ROMs) and a switching PSU that brought the weight down to 50KG. :)

Memory is still Core, this one's got 2 x 8KB Core cards.

Unfortunately some of the gold-plated ROM chips got badly corroded so I'm busy finding replacements. Everything else seems pristine.
Click to expand...
What is this used for in general?

Edit - googled for HP2100A and found that it is for timesharing BASIC.

What types of terminals was used with this? :)
 
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jannievanzyl said:
They're 256 byte ROMs and I'm not sure about the levels and supply. So you might need to build an adaptor board.
Click to expand...
Model number? I can't see clearly from the photo. If you can't read, ask the other guy who has a working machine.

I have number of such chips, it could be programmable devices, must check.

EDIT: Searching for 1816-0056 leads to the floating-point accessory kit: https://archive.org/stream/bitsavers_hp21xxinte_2169442/12901_djvu.txt

These are most likely mask programmable chips, memory organisation unknown, tracing on the PCB must be done to find out pinout. Usually mask programmable chips have a similar compatible OTP or EPROM equivalents. Some EPROM programmers can detect a chip automatically, or serve a suggestion.

As for the corrosion damage, it can be non-destructive, just copper plates on the top are corroded, pins are mostly not affected. Remove the chips (note a position) and clean individually pins and sockets. Take these chips individually on the EPROM programmer and try to read content.

These ceramic cases are very resistant to the atmosphere, not like a cheap plastic ones, so there is a chance that chips are still working.
 
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sajunky said:
Model number? I can't see clearly from the photo. If you can't read, ask the other guy who has a working machine.
Click to expand...

Examples numbered in the pic.

1816-0054
SCM801AL
7332

1816-0055
SCM802AL
7333

1816-0056
SCM803AL
7334

All got the morola logo.
 
ponder said:
Examples numbered in the pic.

1816-0054
SCM801AL
7332

1816-0055
SCM802AL
7333

1816-0056
SCM803AL
7334

All got the morola logo.
Click to expand...
Good job, . LOL.
I edited my post in meantime. It confirms that a link to the floating point kit above is correct. It is optional, so machine should work without, by removing the chips and setting up jumbers to the original position (without kit).
 
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Thanks for all the responses. The FP kit are the ones in the sockets, so I'm not too worried if they don't work. But they are the least affected, so probably are still OK. Think they add 2 or 4 FP instructions to the base instruction base of 80.

The 3 ROMs on the edge of the board are the really badly corroded ones, to the extent that the metal cover on the one fell of when I touched it. I was actually trying to see if it would fall off.

Surprisingly the chip seems intact with all the pins still connected. Wil post a picture.

I've got the IC numbers for each location as well as their memory dumps (256 bytes, each). I must just now find replacement chips.
 
The_Librarian said:
What is this used for in general?

Edit - googled for HP2100A and found that it is for timesharing BASIC.

What types of terminals was used with this? :)
Click to expand...

It was often used for process control and to control scientific instruments. It supported a number of languages but, I suspect, was mostly programmed in assembler.

It had specific terminals, can't recall the model numbers right away. But they guy with the working one uses a terminal emulator on his PC.
 
THe one really cool thing about having core memory cards is that they keeps their memory indefinitely. So this one might still have BASIC loaded in it. :)
 
For peeps in Jhb area into vintage PC stuff (XT onwards);

I'm having an open garage in Sandton this coming Saturday morning where a large number of vintage PC systems, motherboards, cards, drives, keyboards, etc. are up for grabs.

These were donated by one of the members here on MyBB so there is no cost. However you are asked to donate towards the cost of the shipping (more than a ton of stuff shipped from Natal! :) ) if you come and grab some stuff for yourself. Your call on what you think you should donate. (Wine also counts..... ;) )

More details here:

https://www.facebook.com/groups/vintagecomputingsa/permalink/10156832607786170/

and more pics here

https://www.facebook.com/groups/vintagecomputingsa/permalink/10156843598256170/
 

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jannievanzyl said:
For peeps in Jhb area into vintage PC stuff (XT onwards);

I'm having an open garage in Sandton this coming Saturday morning where a large number of vintage PC systems, motherboards, cards, drives, keyboards, etc. are up for grabs.

These were donated by one of the members here on MyBB so there is no cost. However you are asked to donate towards the cost of the shipping (more than a ton of stuff shipped from Natal! :) ) if you come and grab some stuff for yourself. Your call on what you think you should donate. (Wine also counts..... ;) )

More details here:

https://www.facebook.com/groups/vintagecomputingsa/permalink/10156832607786170/

and more pics here

https://www.facebook.com/groups/vintagecomputingsa/permalink/10156843598256170/
Click to expand...
Not a member of Facebook.

To late for Black Friday specials and when CyberMonday is passing, the only proper thread is: https://mybroadband.co.za/forum/threads/the-mybb-pay-it-forward-thread.535655/

And collectors can afford costs when searching for gems. .LOL.

Seriously, I'm still using two 2005 laptops (HP and Thinkpad) and there are some notebooks without power supply, our gardener would enjoy music. Any top quality sound cards, BTW?
 
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