Found these inside a non-working 71B
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11-18-2020, 04:14 PM
Post: #141
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RE: Found these inside a non-working 71B
As a fan of the 71B i have perused this entire stream many times, fun project! Wish it was me who had found this "FrankenCalc" and would have had the chance to work on resuscitating this "baby".
Paul Berger, if you are still actively listening in on the postings, I would be very interested in understanding how you made the front port outlet mentioned in bold below. I do have a "beyond repair" TITAN with wires sticking out everywhere, but 1: it is not very pretty and 2: I can't test (read: Play with) the other TITANs I have. Therefore I have contemplated to build a front-port-plug with a donor module - but have not come as far as making it happen. Maybe I would/could/should borrow from your design and save some time. Please? (03-11-2018 07:31 PM)Paul Berger (Canada) Wrote:(03-11-2018 06:09 PM)MikeSD Wrote: Dave,The way that is wired it should not it looks loke they broke into the chain at the end so the only thing that would not work is the HP-IL. You can check the chain U6 Din is connected to +5V, U6 Dout to U7 Din U7 Dout to U8 Din U8 Dout to U9 Din (bottom of two Roms ) U9 Dout to Din of top ROM. your picture showing the edge on vie confirms that Dout from the top ROM is where the RAM and "FORTH" modules are inserted. The OS ROM is hard addressed and is not part of a chain. |
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11-18-2020, 07:01 PM
Post: #142
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RE: Found these inside a non-working 71B
I made my adapter from a 4K module. I removed all the chips off the little circuit card inside and removed all of the copper trace that I could until I was left with a bare board with just the bus connector pins. I then cut a hole in the front of the shell to fit a small pitch connector, glued in the connector and wired it up to the pins of the bus connector. Initially when I did this my main purpose was to make up a plugin to disable the onboard OS ROMs so I could use a later version loaded on a FRAM module, but I was also curious about the signal timing so I expanded its function.
You can also pick up all of the bus signals on the pins for the card reader, and those have the advantage of being on the same board as the CPU which could come in handy if you have a connection problem between the CPU card and the memory / I/O card. Paul. |
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11-18-2020, 07:26 PM
(This post was last modified: 11-19-2020 07:15 AM by KimH.)
Post: #143
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RE: Found these inside a non-working 71B
Thanks Paul!
I thought (hoped) it could be a less invasiv proces than to break the module, but as Germans would say “everybody cooks with water, there are only so many ways”. the card reader option is not as neat, can’t be moved from device to device. I’ll post an image once I am done. (11-18-2020 07:01 PM)Paul Berger (Canada) Wrote: I made my adapter from a 4K module. I removed all the chips off the little circuit card inside and removed all of the copper trace that I could until I was left with a bare board with just the bus connector pins. I then cut a hole in the front of the shell to fit a small pitch connector, glued in the connector and wired it up to the pins of the bus connector. Initially when I did this my main purpose was to make up a plugin to disable the onboard OS ROMs so I could use a later version loaded on a FRAM module, but I was also curious about the signal timing so I expanded its function. |
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11-18-2020, 08:00 PM
(This post was last modified: 11-18-2020 08:02 PM by Paul Berger (Canada).)
Post: #144
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RE: Found these inside a non-working 71B
(11-18-2020 07:26 PM)KimH Wrote: Thanks Paul! You could probably do it without destroying the module but it might make it hard to fit the connector inside. Since I had a FRAM a 4K module was deemed expendable. Paul. |
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