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Date: Thu, 3 Apr 1997 16:02:30 -0500
Reply-To: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> Sender: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> From: David Wise <david_wise@PHOENIX.COM>
Subject: CM> 1620 (Operating vintage computers as a hobby)
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______________________________________________________________________
Community Memory: Discussion List on the History of Cyberspace ______________________________________________________________________
Does anybody else have a vintage computer that they keep in running order? I'd love to get in touch with people, and compare notes. I have a 1620, 20k paper tape Model I. I even use vintage tools for maintenance.
Last month I powered it up after some years of sitting, and it stopped with an MBR check. I fired up my Tektronix 535 oscilloscope, and narrowed it down to a couple of transistors gone bad, which I replaced. That scope is the same age as the Tek 310, the model that IBM recommended to CE's for 1620 field service.
Does anyone have any spare parts? I want to keep going as long as possible, but there are many bits for which I can't fashion a replacement, and everything's on the rising end of the Bathtub Curve. Anyone care to part with a 1620-special Flexowriter? I could use it for offline listings and editing. The console typewriter is pretty tired, and I hate to use it more than absolutely necessary.
I would love to put it in a museum and do "live" demonstration runs. I talked to the Smithsonian once, and they wanted it, but were unwilling to pay for the shipping.
I got the machine from the University of Portland (Oregon) which scrapped it in 1980, the year I graduated. They had hooked the PT reader to a PDP8/e (the 150cps 1621 is way faster than an ASR33, even though it's rough on tapes). I had lusted after the whole assortment ever since I saw it in a dusty back room, and one day the 1620 was out in the hall. I ran to the dean's office, and the answer was...
YES!
I danced with excitement. I'd been a dumpster-diver ever since I was a kid.
This was the biggest haul ever!
A classmate who owned a moving van helped me get it home. First we stopped at a gas station and I blew out the dust with a compressed-air hose. Whew! At home, my father jittered as the basement stairs creaked under the weight. We did it in pieces. I removed the card gates and stripped the rest down to a skeleton (it took hours), but it was still the heaviest thing that had ever gone in.
U of P had gotten it from Vernonia High School (small out of the way place in the coastal mountains) who got it from Pettijohn Engineering, a civil engineering firm. The 1960-dated bill of sale read $85000. The lead programmer was Waldo J. Richards. WJR, are you out there?
I got boxes and boxes of software with it but I threw some out. Who cares about payroll and bookkeeping? I still have several assemblers and compilers, some math, and some engineering stuff.
I eagerly studied the schematics, and eventually made some modifications. First I did a 10Hz single-step for blinkenlight demos. Yes, I had the "Achtung..." sign on the wall above it. Then I tried running the strange One-Pass SPS assembler, and it crashed. Eventually I found out that it wouldn't run unless I disabled Indirect Addressing, so I wired another spare console switch to do that. I got tired of retyping an entire line if I made a mistake (provided the program allowed you to retype - if it didn't have a
console switch test for retries, you were S.O.L.), so I spent months creating my crowning glory: backspace on typewriter input. I had to wire in nearly every spare logic gate in the backplane to do it. My 1620 is probably the only one in the world that can do this. The things I did when I had spare time.
I'd like to hear about shops that modded their machines. Was it ever done? I suppose IBM took a dim view :-) But some mods were as simple as plugging in new cards, and if you owned the machine outright and were doing your own maintenance, who could stop you?
When I was working at Tek, I ran into another Tekkie who had a 1620. His core memory was dead, and he wanted me to fashion a solid-state replacement. He left me his set of schematics, but I never got around to it, and eventually got laid off. I wonder what happened to him and his 1620.
PAGING KEN CAIRNS!
Once in a while I think about writing a mini-Forth, but the I/O is so weird.
Over the years, it's been a lot of fun...
David Wise (david_wise@phoenix.com)
______________________________________________________________________
Reply-To: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> Sender: "CYHIST Community Memory: Discussion list on the History of
Cyberspace" <CYHIST@MAELSTROM.STJOHNS.EDU> From: David Wise <david_wise@PHOENIX.COM>
Subject: CM> 1620 (Operating vintage computers as a hobby)
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
______________________________________________________________________
Community Memory: Discussion List on the History of Cyberspace ______________________________________________________________________
Does anybody else have a vintage computer that they keep in running order? I'd love to get in touch with people, and compare notes. I have a 1620, 20k paper tape Model I. I even use vintage tools for maintenance.
Last month I powered it up after some years of sitting, and it stopped with an MBR check. I fired up my Tektronix 535 oscilloscope, and narrowed it down to a couple of transistors gone bad, which I replaced. That scope is the same age as the Tek 310, the model that IBM recommended to CE's for 1620 field service.
Does anyone have any spare parts? I want to keep going as long as possible, but there are many bits for which I can't fashion a replacement, and everything's on the rising end of the Bathtub Curve. Anyone care to part with a 1620-special Flexowriter? I could use it for offline listings and editing. The console typewriter is pretty tired, and I hate to use it more than absolutely necessary.
I would love to put it in a museum and do "live" demonstration runs. I talked to the Smithsonian once, and they wanted it, but were unwilling to pay for the shipping.
I got the machine from the University of Portland (Oregon) which scrapped it in 1980, the year I graduated. They had hooked the PT reader to a PDP8/e (the 150cps 1621 is way faster than an ASR33, even though it's rough on tapes). I had lusted after the whole assortment ever since I saw it in a dusty back room, and one day the 1620 was out in the hall. I ran to the dean's office, and the answer was...
YES!
I danced with excitement. I'd been a dumpster-diver ever since I was a kid.
This was the biggest haul ever!
A classmate who owned a moving van helped me get it home. First we stopped at a gas station and I blew out the dust with a compressed-air hose. Whew! At home, my father jittered as the basement stairs creaked under the weight. We did it in pieces. I removed the card gates and stripped the rest down to a skeleton (it took hours), but it was still the heaviest thing that had ever gone in.
U of P had gotten it from Vernonia High School (small out of the way place in the coastal mountains) who got it from Pettijohn Engineering, a civil engineering firm. The 1960-dated bill of sale read $85000. The lead programmer was Waldo J. Richards. WJR, are you out there?
I got boxes and boxes of software with it but I threw some out. Who cares about payroll and bookkeeping? I still have several assemblers and compilers, some math, and some engineering stuff.
I eagerly studied the schematics, and eventually made some modifications. First I did a 10Hz single-step for blinkenlight demos. Yes, I had the "Achtung..." sign on the wall above it. Then I tried running the strange One-Pass SPS assembler, and it crashed. Eventually I found out that it wouldn't run unless I disabled Indirect Addressing, so I wired another spare console switch to do that. I got tired of retyping an entire line if I made a mistake (provided the program allowed you to retype - if it didn't have a
console switch test for retries, you were S.O.L.), so I spent months creating my crowning glory: backspace on typewriter input. I had to wire in nearly every spare logic gate in the backplane to do it. My 1620 is probably the only one in the world that can do this. The things I did when I had spare time.
I'd like to hear about shops that modded their machines. Was it ever done? I suppose IBM took a dim view :-) But some mods were as simple as plugging in new cards, and if you owned the machine outright and were doing your own maintenance, who could stop you?
When I was working at Tek, I ran into another Tekkie who had a 1620. His core memory was dead, and he wanted me to fashion a solid-state replacement. He left me his set of schematics, but I never got around to it, and eventually got laid off. I wonder what happened to him and his 1620.
PAGING KEN CAIRNS!
Once in a while I think about writing a mini-Forth, but the I/O is so weird.
Over the years, it's been a lot of fun...
David Wise (david_wise@phoenix.com)
______________________________________________________________________
