Tales from the Repair Workshop 6/12 & 6/13, 2021
I have two tales to tell about the repair workshop that are funny, but I won't tell them here. You will have to ask me in person, but I intend to repeat them over and over again until people get sick of me telling them. Then I will tell new stories. The repair workshop was well attended this time with the usual suspects and some new ones as well. Jeff Salzman and Herb got the H89 working! So now it is available for operation and display in the museum. I thank them very much for all their hard work in working on the repair of the machine and getting it into operation. It has been sitting in the museum for years as a static display and it is lovely to see it actually display something on the screen and operate. We have Vcalc and 1 or 2 other pieces of software (I forget what they are at the moment). Jeff Salzman intends to make other software disks available to the museum the next time he comes or he can give me the disks at the July repair workshop @ System Source. David Gesswein worked on the PDP 8. The original intention was to train me on papertape and software loading, but he discovered that there were some faults. He had suspected it to be one problem on two cards, but that wasn't the case. He found out one of the diodes needed replacement and it worked better. However there was another problem on another card, but he ran out of time and will take the card home to troubleshoot and narrow down the problem. I know that others were working on various things, but I didn't have time to get details. Always a fun time at the workshop and lots of stuff getting fixed. Going to Brick House Tap & Tavern was a welcome change. Main Street Bar and Grill is nice, but we have overdone it and needed to change up things. I'm considering doing an outdoor grill at the August repair workshop cooking burgers and hotdogs. Next repair workshops are: July 10 & 11 @ System Source : SIGNUP <https://docs.google.com/spreadsheets/d/1KROoCNqTiTWgsXvijGBqvNblZa8weS6a8hEkXpmO_Ao/edit?usp=sharing> August 14 & 15 @ InfoAge: SIGNUP <https://docs.google.com/spreadsheets/d/1J028DlSdvSUlh3BsrGfmalHQ9qbFfPSUQa9Exn1aoJs/edit?usp=sharing> ========================================= Jeff Brace Vice President & Board Member Vintage Computer Festival East Show-runner Vintage Computer Federation is a 501c3 charity http://www.vcfed.org/ jeffrey@vcfed.org
Sorry I missed it! I guess I have to wait until August. No idea where System Source is : ). Sent from Yahoo Mail for iPhone On Monday, June 14, 2021, 10:35 AM, Jeffrey Brace via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote: I have two tales to tell about the repair workshop that are funny, but I won't tell them here. You will have to ask me in person, but I intend to repeat them over and over again until people get sick of me telling them. Then I will tell new stories. The repair workshop was well attended this time with the usual suspects and some new ones as well. Jeff Salzman and Herb got the H89 working! So now it is available for operation and display in the museum. I thank them very much for all their hard work in working on the repair of the machine and getting it into operation. It has been sitting in the museum for years as a static display and it is lovely to see it actually display something on the screen and operate. We have Vcalc and 1 or 2 other pieces of software (I forget what they are at the moment). Jeff Salzman intends to make other software disks available to the museum the next time he comes or he can give me the disks at the July repair workshop @ System Source. David Gesswein worked on the PDP 8. The original intention was to train me on papertape and software loading, but he discovered that there were some faults. He had suspected it to be one problem on two cards, but that wasn't the case. He found out one of the diodes needed replacement and it worked better. However there was another problem on another card, but he ran out of time and will take the card home to troubleshoot and narrow down the problem. I know that others were working on various things, but I didn't have time to get details. Always a fun time at the workshop and lots of stuff getting fixed. Going to Brick House Tap & Tavern was a welcome change. Main Street Bar and Grill is nice, but we have overdone it and needed to change up things. I'm considering doing an outdoor grill at the August repair workshop cooking burgers and hotdogs. Next repair workshops are: July 10 & 11 @ System Source : SIGNUP <https://docs.google.com/spreadsheets/d/1KROoCNqTiTWgsXvijGBqvNblZa8weS6a8hEkXpmO_Ao/edit?usp=sharing> August 14 & 15 @ InfoAge: SIGNUP <https://docs.google.com/spreadsheets/d/1J028DlSdvSUlh3BsrGfmalHQ9qbFfPSUQa9Exn1aoJs/edit?usp=sharing> ========================================= Jeff Brace Vice President & Board Member Vintage Computer Festival East Show-runner Vintage Computer Federation is a 501c3 charity http://www.vcfed.org/ jeffrey@vcfed.org
On Mon, Jun 14, 2021 at 10:38 AM laurakid <laurakid7@yahoo.com> wrote:
Sorry I missed it! I guess I have to wait until August. No idea where System Source is : ).
Here is the System Source Museum website: https://museum.syssrc.com/ Here is the Google Map for it in Hunt Valley, MD which is north of Baltimore: https://goo.gl/maps/irqWovzfXshFBUTm7 It is a wonderful museum run by our national board member Bob Roswell and I encourage every to visit this well put together museum!
Sent from Yahoo Mail for iPhone <https://overview.mail.yahoo.com/?.src=iOS>
On Monday, June 14, 2021, 10:35 AM, Jeffrey Brace via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:
I have two tales to tell about the repair workshop that are funny, but I won't tell them here. You will have to ask me in person, but I intend to repeat them over and over again until people get sick of me telling them. Then I will tell new stories.
The repair workshop was well attended this time with the usual suspects and some new ones as well.
Jeff Salzman and Herb got the H89 working! So now it is available for operation and display in the museum. I thank them very much for all their hard work in working on the repair of the machine and getting it into operation. It has been sitting in the museum for years as a static display and it is lovely to see it actually display something on the screen and operate. We have Vcalc and 1 or 2 other pieces of software (I forget what they are at the moment). Jeff Salzman intends to make other software disks available to the museum the next time he comes or he can give me the disks at the July repair workshop @ System Source.
David Gesswein worked on the PDP 8. The original intention was to train me on papertape and software loading, but he discovered that there were some faults. He had suspected it to be one problem on two cards, but that wasn't the case. He found out one of the diodes needed replacement and it worked better. However there was another problem on another card, but he ran out of time and will take the card home to troubleshoot and narrow down the problem.
I know that others were working on various things, but I didn't have time to get details. Always a fun time at the workshop and lots of stuff getting fixed. Going to Brick House Tap & Tavern was a welcome change. Main Street Bar and Grill is nice, but we have overdone it and needed to change up things. I'm considering doing an outdoor grill at the August repair workshop cooking burgers and hotdogs.
Next repair workshops are: July 10 & 11 @ System Source : SIGNUP < https://docs.google.com/spreadsheets/d/1KROoCNqTiTWgsXvijGBqvNblZa8weS6a8hEk...
August 14 & 15 @ InfoAge: SIGNUP < https://docs.google.com/spreadsheets/d/1J028DlSdvSUlh3BsrGfmalHQ9qbFfPSUQa9E...
========================================= Jeff Brace Vice President & Board Member Vintage Computer Festival East Show-runner Vintage Computer Federation is a 501c3 charity http://www.vcfed.org/ jeffrey@vcfed.org
Dmitry did a cool swap of an amber CRT tube into an Atari ST white CRT monitor. E3u3rCaWQAIqxO2 (969×2048) (twimg.com) <https://pbs.twimg.com/media/E3u3rCaWQAIqxO2?format=jpg&name=large> On Mon, Jun 14, 2021 at 10:36 AM Jeffrey Brace via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:
I know that others were working on various things, but I didn't have time to get details.
Not from Atari, but a MultiSync monitor will do both.
On Jun 14, 2021, at 10:59 AM, Ethan O'Toole via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:
Dmitry did a cool swap of an amber CRT tube into an Atari ST white CRT monitor.
Ah Atari ST. You can have color, or you can have HiRez, but you can't have both.
- Ethan
Not from Atari, but a MultiSync monitor will do both.
But.. then it doesn't match the computer case. I actually have an Atari ST color monitor and I want to do the thing where you swap out component inside so you can make the picture larger on the tube. As shipped from what I read the parts couldn't handle the power draw and would fail prematurely so Atari backed down the image size on the tube so they wouldn't blow up. You got one job Atari ST... that is Notator and Cubase. Maybe MidiMaze too. - Ethan
Just get some TV tools (plastic screwdrivers essentially) and adjust the H and W pots on the TV board, careful not to touch the tube and die. I did this on several of the mono ST screens which shipped displaying postage-stamp-sized images. Was pretty easy. And I was 13. bp On Mon, Jun 14, 2021 at 1:02 PM Ethan O'Toole via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:
Not from Atari, but a MultiSync monitor will do both.
But.. then it doesn't match the computer case.
I actually have an Atari ST color monitor and I want to do the thing where you swap out component inside so you can make the picture larger on the tube. As shipped from what I read the parts couldn't handle the power draw and would fail prematurely so Atari backed down the image size on the tube so they wouldn't blow up.
You got one job Atari ST... that is Notator and Cubase.
Maybe MidiMaze too.
- Ethan
-- Heisenberg may have slept here.
The adjustments are easy, just make sure you don’t touch any high-voltage connections! Sent from: My extremely complicated, hand held electronic device.
On Jun 14, 2021, at 3:14 PM, Blake Patterson via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:
Just get some TV tools (plastic screwdrivers essentially) and adjust the H and W pots on the TV board, careful not to touch the tube and die. I did this on several of the mono ST screens which shipped displaying postage-stamp-sized images. Was pretty easy. And I was 13.
bp
On Mon, Jun 14, 2021 at 1:02 PM Ethan O'Toole via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:
Not from Atari, but a MultiSync monitor will do both.
But.. then it doesn't match the computer case.
I actually have an Atari ST color monitor and I want to do the thing where you swap out component inside so you can make the picture larger on the tube. As shipped from what I read the parts couldn't handle the power draw and would fail prematurely so Atari backed down the image size on the tube so they wouldn't blow up.
You got one job Atari ST... that is Notator and Cubase.
Maybe MidiMaze too.
- Ethan
-- Heisenberg may have slept here.
Just get some TV tools (plastic screwdrivers essentially) and adjust the H and W pots on the TV board, careful not to touch the tube and die. I did this on several of the mono ST screens which shipped displaying postage-stamp-sized images. Was pretty easy. And I was 13. bp
I have the plastic tools (Arcade monitors!) but I read on Atari Age (or maybe Amibay) that there is a component that needs to be swapped out on the color monitor before you make the image fill the monitor. They purposely undersized the image because it would strain the part and kill it. There was a pointer to a zip file with the old school text file that describes it and what to replace. I just googled but not finding the post. - Ethan
That’s interesting. Would like to hear the details on that. I always just assumed the border was done for a couple reasons. One was there were parts of the max resolution of the screen not used (320x200) vs ~704x262 max for progressive when talking NTSC and if you run some hacks that over scan, the picture will be cut off on the top and bottom if you mess with adjustments. Just like today having black bars on top and bottom for unused pixels __ You will probably mess up the aspect ratio. The other reason too I again assume is the distortion on the edges of a curved CRT, lines may bow, etc. Would love to see the specs of the color monitors that I think are Philips made. On 6/14/21, 4:10 PM, "vcf-midatlantic on behalf of Ethan O'Toole via vcf-midatlantic" <vcf-midatlantic-bounces@lists.vcfed.org on behalf of vcf-midatlantic@lists.vcfed.org> wrote: > Just get some TV tools (plastic screwdrivers essentially) and adjust the H and W pots on the TV board, careful not to > touch the tube and die. I did this on several of the mono ST screens which shipped displaying postage-stamp-sized images. > Was pretty easy. And I was 13. > bp I have the plastic tools (Arcade monitors!) but I read on Atari Age (or maybe Amibay) that there is a component that needs to be swapped out on the color monitor before you make the image fill the monitor. They purposely undersized the image because it would strain the part and kill it. There was a pointer to a zip file with the old school text file that describes it and what to replace. I just googled but not finding the post. - Ethan
As a follow up: https://aldabase.com/atari-st-fullscreen-demos-history/ This talks about all the tricks folks did to "unlock" the extra resolution. On 6/14/21, 4:48 PM, "vcf-midatlantic on behalf of Wil Birkmaier via vcf-midatlantic" <vcf-midatlantic-bounces@lists.vcfed.org on behalf of vcf-midatlantic@lists.vcfed.org> wrote: That’s interesting. Would like to hear the details on that. I always just assumed the border was done for a couple reasons. One was there were parts of the max resolution of the screen not used (320x200) vs ~704x262 max for progressive when talking NTSC and if you run some hacks that over scan, the picture will be cut off on the top and bottom if you mess with adjustments. Just like today having black bars on top and bottom for unused pixels __ You will probably mess up the aspect ratio. The other reason too I again assume is the distortion on the edges of a curved CRT, lines may bow, etc. Would love to see the specs of the color monitors that I think are Philips made. On 6/14/21, 4:10 PM, "vcf-midatlantic on behalf of Ethan O'Toole via vcf-midatlantic" <vcf-midatlantic-bounces@lists.vcfed.org on behalf of vcf-midatlantic@lists.vcfed.org> wrote: > Just get some TV tools (plastic screwdrivers essentially) and adjust the H and W pots on the TV board, careful not to > touch the tube and die. I did this on several of the mono ST screens which shipped displaying postage-stamp-sized images. > Was pretty easy. And I was 13. > bp I have the plastic tools (Arcade monitors!) but I read on Atari Age (or maybe Amibay) that there is a component that needs to be swapped out on the color monitor before you make the image fill the monitor. They purposely undersized the image because it would strain the part and kill it. There was a pointer to a zip file with the old school text file that describes it and what to replace. I just googled but not finding the post. - Ethan
On 6/14/21 10:58 AM, Jeff Salzman via vcf-midatlantic wrote:
Dmitry did a cool swap of an amber CRT tube into an Atari ST white CRT monitor.
I didn't know you could do that! I just recall that the B&W monitor had a really funky refresh and if something broke you could set the B&W monitor on fire. Happened to a friend of mine. Lots of smoke because of a broken pin (I think). -- Linux Home Automation Neil Cherry ncherry@linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies
Straight 8 work Report before I arrived was that the paper tape text punch program was no longer running. It was unclear if it needed to be reloaded or machine had more problems. Found memory was not operating properly. 2 diodes replaced fixing one memory issue and hopefully fixing another. Failure of accumulator card late in workshop prevented verification of memory fix. Machine not useable until I fix and return the accumulator card. Hopefully I can fix at home and send it back with someone at the System Source event next month. TLDR version: Initial testing showed the Computer would not reliably read or write memory. Checking signals on memory state card MD16 the flip flops were not always set back to idle state at the end of the memory cycle. Traced to the end of cycle signal from delay line in MC/MD18 not always present. The signal amplitude was gettting reduced as it went down the delay line taps. By the time it got to CP output it was marginal on triggering the output gate. With testing and swapping with card in MC/MD17 it did not look like the delay line card was the issue. Looking further the input pulse to the delay line was only 25 ns wide coming from W607 in MC19. This seemed short for the PDP logic. Checking the W607 datasheet its output should be a 70ns pulse. The 25ns is too short for the bandwidth of the delay line to pass without significant loss. Checking card for the second time I found one of the diodes had .7V drop measured with my meter instead of typical .6. Replacing diode got the pulse to proper 70ns and fixed the memory operation. Diode replaced was D5 on W607 rev D schematic. The front panel had been getting flakey with examine and deposit double incrementing and other behaviors. I had added a cap to increase the debounce time but only helped some. I went through my contact cleaners and treatments on the momemtary switches. They seemed to work well after so removed the extra capacitor and they still worked well. Entered the moving light test program without problems and it ran fine. Long ago I had put a temporary cap in on the processor backplane to replace a failed one. I replaced it with what I though was a match for the original cap and also a similar cap in case it was going bad. Caps were supposed to be exact match but found the one I removed was TE-1304 10uF 50V and the one I had with me was TE-1507 10uF 150V. Not going to matter just annoying that I got things mixed up. Ran the 5 processor diagnostics without error. The memory diagnostics failed intermitently. Checked the G603 memory selection matrix cards since they caused similar problem previously. Found and replaced one bad diode on second from left card. Thought everything would be good now but the machine decided to toy with me. Had a stuck at 1 fault for memory data bit 10. Traced to G007 card which input for core looked good but output was bad. Nothing found wrong on card with DVM. Put it back in and worked fine. Then machine still not running properly. When testing I noticed AC8 wasn't 1 when MB8 was 1 examining memory. MB and AC should both get the value from memory. The problem moved when I swapped R210 AC8 and AC9 card. After the machine was off for a while then turned back on the front panel light would light but would go out after a few seconds when reading memory. The fault also dependent on the value read from memory. If memory has 0014 AC gets 4. 0034 loads correctly and 0010 loads correctly. R210 is a complex card and little time was left so I packed up and brought the card home to hopefully fix. It has tape on it indicating I had problems with it previously. Haven't checked to see if it will reproduce in my machine.
Hello! I should contribute here, that I spent the time getting my Compaq Portable 2 system repaired. While the screen shows signs of age, the system itself works. I believe I'll still be able to apply the system for its original purposes. I found the group, especially Ian, very helpful. ----- Gregg C Levine gregg.drwho8@gmail.com "This signature fought the Time Wars, time and again." On Mon, Jun 14, 2021 at 10:35 AM Jeffrey Brace via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:
I have two tales to tell about the repair workshop that are funny, but I won't tell them here. You will have to ask me in person, but I intend to repeat them over and over again until people get sick of me telling them. Then I will tell new stories.
The repair workshop was well attended this time with the usual suspects and some new ones as well.
Jeff Salzman and Herb got the H89 working! So now it is available for operation and display in the museum. I thank them very much for all their hard work in working on the repair of the machine and getting it into operation. It has been sitting in the museum for years as a static display and it is lovely to see it actually display something on the screen and operate. We have Vcalc and 1 or 2 other pieces of software (I forget what they are at the moment). Jeff Salzman intends to make other software disks available to the museum the next time he comes or he can give me the disks at the July repair workshop @ System Source.
David Gesswein worked on the PDP 8. The original intention was to train me on papertape and software loading, but he discovered that there were some faults. He had suspected it to be one problem on two cards, but that wasn't the case. He found out one of the diodes needed replacement and it worked better. However there was another problem on another card, but he ran out of time and will take the card home to troubleshoot and narrow down the problem.
I know that others were working on various things, but I didn't have time to get details. Always a fun time at the workshop and lots of stuff getting fixed. Going to Brick House Tap & Tavern was a welcome change. Main Street Bar and Grill is nice, but we have overdone it and needed to change up things. I'm considering doing an outdoor grill at the August repair workshop cooking burgers and hotdogs.
Next repair workshops are: July 10 & 11 @ System Source : SIGNUP <https://docs.google.com/spreadsheets/d/1KROoCNqTiTWgsXvijGBqvNblZa8weS6a8hEkXpmO_Ao/edit?usp=sharing> August 14 & 15 @ InfoAge: SIGNUP <https://docs.google.com/spreadsheets/d/1J028DlSdvSUlh3BsrGfmalHQ9qbFfPSUQa9Exn1aoJs/edit?usp=sharing> ========================================= Jeff Brace Vice President & Board Member Vintage Computer Festival East Show-runner Vintage Computer Federation is a 501c3 charity http://www.vcfed.org/ jeffrey@vcfed.org
participants (11)
-
Blake Patterson -
David Gesswein -
Ethan O'Toole -
Gregg Levine -
Jeffrey Brace -
jsalzman＠gmail.com -
laurakid -
Neil Cherry -
Peter Fletcher -
Sentrytv -
Wil Birkmaier