test-drb

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101090 discussions

by michael.99.thompson＠gmail.com

> > From: Bryan Longram <Driverless at protonmail.com> > Subject: Wanting some help with a PDP-8/a > > I acquired a non-functional PDP-8/A several months ago and in that time > I've replaced all the outwardly damaged parts and have gotten the machine > to power on with no issues. However the problem I've been having now that I > can't quite seem to pin down is that every time I power the machine the > address field is displayed as 07777 and the value field is displayed as > 7777. Attempting to change addresses or the value of the address doesn't > work as I can enter the value just fine but upon entering the Load Address > button it defaults back to being all sevens. I am in the process of repairing three 8/a Programmer's Panels. Two panels had bad ribbon cables. A good panel exhibited the same behavior as yours when used with the bad cables. I was able to cut the keying peg off two IDE disk cables to try as replacement cables. They IDE cables don't fit well, but do work. I will make new replacement cables for all three panels. -- Michael Thompson

6 years

Has My VAXmate Flyback Transformer Failed?

by robert.jarratt＠ntlworld.com

I have been looking at the flyback transformer from my VAXmate. I think it could have failed but I can't be completely sure. I have posted a description here: https://robs-old-computers.com/2020/05/12/vaxmate-flyback-transformer/ Can anyone offer an opinion? Thanks Rob

6 years

DS20E power supply question

by bob＠jfcl.com

I have a DS20E Alpha machine. It's pretty fully configured, with two 666 MHz CPUs, 4GB RAM and 4x10K SCSI drives. In other words, it's a real power hog. It has three power supply modules installed, and if I understand the configuration rules then at least two should be required to run the machine and the third is a hot spare. But, when do SHOW POWER at the SRM prompt, I get P00>show power Status Power Supply 0 * BAD * Power Supply 1 not present Power Supply 2 not present System Fan 0 good System Fan 1 * BAD * CPU Fans good Temperature good What? If I believe that then I have no functioning power supplies installed?!? At this point I should mention that the machine boots VMS and runs just fine. Obviously something is not telling me the truth. Does anybody know what would cause this? BTW, what do the red LEDs on the front of the power supply modules mean? Is LED ON a good thing (i.e. power OK) or a bad thing (i.e. fault)? FWIW, none of the LEDs on my three power supplies is on. Oh, and it's right about System fan #1 - one of the fans is not running. I don't know if it's seized up, or if it's related to the power supply issue. Thanks, Bob

6 years

unibus scsi board

by aek＠bitsavers.org

mislabeled as qbus https://www.ebay.com/itm/143603725400

6 years

Re: Looking for a pair of DEC RL02 drives, working or otherwise

by stephenbuck＠mac.com

Thanks for the lead David, I'll email him to see what he has. Steve

6 years

SEL 810A running lunar lander

by mooreericnyc＠gmail.com

https://youtu.be/L743MjJthHY I recently got my SEL 810A working. I hope you guys enjoy the video :). -Eric

6 years

SEL 810A running lunar lander

by boris＠summitclinic.com

Nice how machines from that era were well made enough to still work. Remember that Lunar Lander game from about 1970. Version I played was written in FOCAL and run on a TSS-8. Should try it out on some kids who think they're great gamers and see how fast they catch on - once we were able to land without crashing we'd see who could come down at lowest speed or have most fuel left over after a successful landing. >https://youtu.be/L743MjJthHY > >I recently got my SEL 810A working. I hope you guys enjoy the video :). > >-Eric

6 years

Wanting some help with a PDP-8/a

by Driverless＠protonmail.com

I acquired a non-functional PDP-8/A several months ago and in that time I've replaced all the outwardly damaged parts and have gotten the machine to power on with no issues. However the problem I've been having now that I can't quite seem to pin down is that every time I power the machine the address field is displayed as 07777 and the value field is displayed as 7777. Attempting to change addresses or the value of the address doesn't work as I can enter the value just fine but upon entering the Load Address button it defaults back to being all sevens. I've made sure the pins on the CPU board are set so it should start at address 0, the advanced options are also all turned off and as far as I can tell there's nothing out of the ordinary with the pin settings on the IO board. I'm fairly certain at this point that the issue is with the Programmer's Panel but I'm not 100% sure. I've done some further testing using advice I got from users over at the Vintage Computer Forum and SR and LSR work as intended, I can enter a value into SR and then view it at a later time. Something interesting I did find was while checking over the CPU I was looking at the switches on it and while S1-1 was set as expected S1-7 was also on which is the CPU autostart disabled feature. Upon powering the computer back on after turning S1-7 off both the ADDRS and DISP displays show a single 0. I thought I was on the right track though now the panel doesn't work as if the panel lock was toggle even though it's not, not even the read functions and SR are working. Switching S1-7 back on reverts the problem back to what it was before and far as I know all the voltages on the power supply are correct. Any help would be appreciated, even if it's just a push in the right direction.

6 years

Looking for a pair of DEC RL02 drives, working or otherwise

by stephenbuck＠mac.com

Looking for a pair of DEC RL02 drives, working or otherwise, for a PDP-11 restoration destined for a local computer museum in Boulder, Colorado. It's fine if it's not working - I'm happy to try and get it up and running. Thanks! Here's a link to the restoration blog: http://headspinlabs.wordpress.com

6 years

Compaq opal 15" monitor

by sales＠elecplus.com

Someone asked for one of these a long time ago. I have one tested and working; needs a good cleaning. Make offer; local pickup only. Cindy Croxton Electronics Plus 1613 Water Street Kerrville, TX 78028 830-370-3239 cell sales at elecplus.com -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

6 years

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