- cctalk - classiccmp.org

by Stephen Pereira

Good afternoon to all, I am starting the process of selling off some of my vintage computer systems, so as to not burden anyone I leave behind. The systems I list here are available for viewing in Bedford, NH, just west of Manchester, NH. Anyone interested can send me an e-mail message and we can set up an appointment for you to visit. Cash and Carry, of course, and reasonable offers will be considered. Altair 8800c — $2500 I constructed this system early in 2019. I built the front panel and front panel interface boards, and soldered up the backplane. The rest of the boards were purchased assembled and tested. You can see the Altair 8800c story here: https://deramp.com/altair.html The system is fully tested and working, currently using virtual Altair disk drives via the Deramp application. Plenty of documentation. Single 8 inch disk drive in a dual drive cabinet — $500 This physical disk drive has been paired with the Altair 8800c in the past. Works fine. I included will be an 8 inch disk drive that used to be in this cabinet until the power supply failed. I believe this drive can be repaired. Included will be another 8 inch drive that is the wrong form factor to fit into the cabinet. Purchased on eBay, untested. Altair 680 — $2000 I acquired this system on eBay back at the end of 2018. It was not working, but a bit of troubleshooting discovered bad ram which was replaced. The least significant LED of the address display does not light, but I’ve tested that the proper signals are there. I simply did not want to risk changing out the LED. This system comes with the 4-slot riser, but the connectors are not yet soldered in. No add-in boards. Plenty of documentation. Complete SWTPC 6800 clone system from Corsham Technologies — $400 I acquired this system from Bob at Corsham in the middle of 2018. It is the complete setup, with the full 64K ram and the virtual disk drives. Documentation available at Corsham Technologies: http://www.corshamtech.com <http://www.corshamtech.com/> Northstar Horizon — $800 I purchased this system on eBay as a running system. From time to time I had problems with the top 8K ram on the Horizon 64K ram board. The 64k ram board has been replaced with a Compupro Ram 17 (or clone), works great, no problems. I will include the glitchy Horizon 64K ram board. FYI, a Deramp Virtual Sector Generator works great with this system, eliminating the need for hard sector diskettes. https://deramp.com/vsg.html Thanks for listening! smp - - - Stephen Pereira Bedford, NH 03110 KB1SXE

2 years, 2 months

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Vintage Computer Systems for sale

by Stephen Pereira

Good afternoon to all, I am starting the process of selling off some of my vintage computer systems, so as to not burden anyone I leave behind. The systems I list here are available for viewing in Bedford, NH, just west of Manchester, NH. Anyone interested can send me an e-mail message and we can set up an appointment for you to visit. Cash and Carry, of course, and reasonable offers will be considered. Altair 8800c — $2500 I constructed this system early in 2019. I built the front panel and front panel interface boards, and soldered up the backplane. The rest of the boards were purchased assembled and tested. You can see the Altair 8800c story here: https://deramp.com/altair.html The system is fully tested and working, currently using virtual Altair disk drives via the Deramp application. Plenty of documentation. Single 8 inch disk drive in a dual drive cabinet — $500 This physical disk drive has been paired with the Altair 8800c in the past. Works fine. I included will be an 8 inch disk drive that used to be in this cabinet until the power supply failed. I believe this drive can be repaired. Included will be another 8 inch drive that is the wrong form factor to fit into the cabinet. Purchased on eBay, untested. Altair 680 — $2000 I acquired this system on eBay back at the end of 2018. It was not working, but a bit of troubleshooting discovered bad ram which was replaced. The least significant LED of the address display does not light, but I’ve tested that the proper signals are there. I simply did not want to risk changing out the LED. This system comes with the 4-slot riser, but the connectors are not yet soldered in. No add-in boards. Plenty of documentation. Complete SWTPC 6800 clone system from Corsham Technologies — $400 I acquired this system from Bob at Corsham in the middle of 2018. It is the complete setup, with the full 64K ram and the virtual disk drives. Documentation available at Corsham Technologies: http://www.corshamtech.com <http://www.corshamtech.com/> Northstar Horizon — $800 I purchased this system on eBay as a running system. From time to time I had problems with the top 8K ram on the Horizon 64K ram board. The 64k ram board has been replaced with a Compupro Ram 17 (or clone), works great, no problems. I will include the glitchy Horizon 64K ram board. FYI, a Deramp Virtual Sector Generator works great with this system, eliminating the need for hard sector diskettes. https://deramp.com/vsg.html Thanks for listening! smp - - - Stephen Pereira Bedford, NH 03110 KB1SXE

2 years, 2 months

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IBM VM "CMS" tape format

by Chuck Guzis

Group, Ive got a tape here from what I believe to be a VM system. The structure is unknown to me, although I can possibly take a stab at it. Lots of data between tapemarks that seems to consist of a number of records that start out something like this (translated from EBCIDC): > 00000000 02 43 4d 53 46 30 30 30 31 31 32 30 35 31 31 32 |.CMSF00011205112| > 00000010 34 37 30 37 36 30 31 32 32 32 31 31 30 31 31 31 |4707601222110111| Another example: > 00000000 02 43 4d 53 46 44 41 54 41 20 5f 4e 55 4c 4c 5f |.CMSFDATA _NULL_| > 00000010 3b 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |; | > 00000020 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | The data itself appears to be a bunch of 80 character card images. I found a mention on the old yahoo groups H390-VM discussions, but no clarity was ever shed on the subject. Does anyone know about this tape format? --Chuck

2 years, 2 months

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Any leads on Fairlight sampler that needs repair?

by Ethan O'Toole

Anyone have any leads in USA on a Fairlight CMI or similar that needs repair? S-100 based sampler from the 80s. Would be fun to restore one. - Ethan

2 years, 2 months

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Re: IBM VM "CMS" tape format

by Adam Thornton

Seems like rather than going through MUSIC/SP it'd be easier to just fire up VM/CE 1.2 (which is VM/370 r6) and use CMS TAPE (which is present) directly from the CMS UI. You can probably attach the file you've got as a tape device; not entirely sure Hercules will like the format, but it wouldn't hurt to try. Adam

2 years, 2 months

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WTD: transputer multi-cpu isa card

by Tony Jones

I'd like to get an ISA based transputer card. Something with multiple cpus (so not the B004). A B008 or one of the clones that accepts multiple TRAM modules would be ideal (https://www.geekdot.com/inmos-b008) It doesn't have to be TRAM. I saw this multi-cpu board on ebay.ie but a) it's more than I was hoping to spend b) I can't find any info on it. Whatever I get I want there to be reasonable docs and archived software: https://www.ebay.ie/itm/234283597489 Suggestions on what to look for welcomed. I'm in no rush and good things come to those who wait. I'm in the USA but have family in the UK and go there often so I'm looking on ebay.co.uk Thanks!

2 years, 2 months

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IBM 727 tape drive

by Christian Corti

Hello all, as it will be soon of importance to us, I am seeking for the systems engineering manual and drawings, well, everything about the IBM 727 tape drive (not the 729!). I especially need the module locations charts and the module schematics. I see that there is the CE manual on bitsavers. Eventually, the other manuals are available somewhere, too? Christian

2 years, 2 months

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Tracking Down a RAM Issue in a VT100 (how does the 2114 chip work?)

by Rob Jarratt

I have a non-functioning VT100. I think it is failing in the POST during the RAM check. I don't know for sure because I can't get it to light up the LEDs on the keyboard, however I used my logic analyser (a HP1630G) to see what values were written to the UART to send to the keyboard and I see it sends the values FF then 1, 2, 3, 4 and finally 5. The last value corresponds to the RAM test so I am fairly confident the RAM test is what is failing. I have disassembled the VT100 ROM and if I have understood it correctly it zeroes out the RAM (high address to low) and then for each address (low address to high) it tries first to read back the zero and then writes 0xAA to the location and tries to read that back. I am also confident the 8080 is working OK because I was able to capture an address trace on the ROM that showed it executing the program as per the disassembled ROM. My problem is getting the logic analyser reliably to tell me how each RAM chip is being addressed and what data is being read or written. I am seeing strange values for the addresses (sometimes) and I am not sure I have setup the logic analyser correctly. I have read the datasheet for the 2114 chip and I am not entirely clear that I have understood it correctly. Here is how I have set it up: Trigger on the -ve edge of Chip Select (pin 8) Capture A9-A0 as the address Capture WE as an indication of Read or Write The timing diagrams show the write cycle where the WE signal and CE signal seem to transition at the same time and the data may be only valid a bit later then the CS -ve edge. But this may just be me not knowing how to read the datasheet. Using the +ve edge of CS seems no better. Is there something I am missing about how to analyse how the RAM chips are being used? Thanks Rob

2 years, 2 months

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Concorde cabin display technology?

by Shoppa, Tim

Not quite computer tech but I figure this is the best place to ask: Does anyone recognize the display tech that was used on the Concorde's in-cabin display? Examples: https://samchui.com/wp-content/uploads/2016/02/CON15.jpg https://samchui.com/wp-content/uploads/2016/02/CON16.jpg The display had fully-formed digits and letters, and showed either Mach and Feet, or Temp and MPH. Some pictures show the display in green and others show it in orange - which of course were popular monochrome CRT colors, yet the display looks too "flat" to be a couple CRT's. Those colors were also popular for Electroluminiscent displays which matches the evident "flatness" but I'm not sure I've seen any EL's with fully formed digits like this with no visible segmentation? I want to guess it was individual digits back-projected - which was a popular control-theater display tech at the end of the 20th century - but I can't rule out, say, really well-done edge-lit character plates. In any event there doesn't seem to be any visible jitter up and down between digits that I might expect with either of those technologies. The "FEET" display in the above-referenced JPG's shows some artifacts at the left and right edges which might be a clue? Some pics of the BA Concorde interior had a simple 15-segment and 7-segment green LED display. Don't need help with that one 🙂. Tim N3QE

2 years, 3 months

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OT: Anyone near Glasnevin (Dublin), Ireland (to pick-up an item)?

by Sellam Abraham

I'm looking for someone near Glasnevin near Dublin, Ireland who would be willing to pick up an item for me and ship it to me State-side. Seller will not ship. Thank you in advance. Sellam

2 years, 3 months

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