I'm restoring a Lear Siegler ADM-3A, and I'm not the most CRT-savvy guy around (but I did really enjoy Ian's excellent class at the most recent VCF-E). Attached is a photo of the issue. If I crank the brightness to clearly see the raster, I can see that the text is actually displaying as dark instead of bright. Pointers? Cheers, Garrett
Flip the jumper. Bill Degnan twitter: billdeg vintagecomputer.net On May 21, 2017 4:07 PM, "Garrett Nievin via vcf-midatlantic" < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
I'm restoring a Lear Siegler ADM-3A, and I'm not the most CRT-savvy guy around (but I did really enjoy Ian's excellent class at the most recent VCF-E).
Attached is a photo of the issue. If I crank the brightness to clearly see the raster, I can see that the text is actually displaying as dark instead of bright.
Pointers?
Cheers, Garrett
Garrett, IIRCC look for a small plate (maybe a logo) to the left of the keyboard. Under that plate should be a row of rocker switches one of which should be the solution you seek. Jim On Sun, 21 May 2017, Garrett Nievin via vcf-midatlantic wrote:
Date: Sun, 21 May 2017 16:07:06 -0400 From: Garrett Nievin via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> To: vcf-midatlantic@lists.vintagecomputerfederation.org Cc: Garrett Nievin <gnievin@silvaire.org> Subject: [vcf-midatlantic] ADM-3A display problem
I'm restoring a Lear Siegler ADM-3A, and I'm not the most CRT-savvy guy around (but I did really enjoy Ian's excellent class at the most recent VCF-E).
Attached is a photo of the issue. If I crank the brightness to clearly see the raster, I can see that the text is actually displaying as dark instead of bright.
Pointers?
Cheers, Garrett
js@sdf.org SDF Public Access UNIX System - http://sdf.lonestar.org
there are the switches under the panel next to the keyboard but also on the main board. You have to read the correct manual to the version of terminal, but most have a label to indicate their function. On Tue, May 23, 2017 at 1:17 PM, Jim Scheef via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
Garrett, IIRCC look for a small plate (maybe a logo) to the left of the keyboard. Under that plate should be a row of rocker switches one of which should be the solution you seek. Jim
On Sun, 21 May 2017, Garrett Nievin via vcf-midatlantic wrote:
Date: Sun, 21 May 2017 16:07:06 -0400
From: Garrett Nievin via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> To: vcf-midatlantic@lists.vintagecomputerfederation.org Cc: Garrett Nievin <gnievin@silvaire.org> Subject: [vcf-midatlantic] ADM-3A display problem
I'm restoring a Lear Siegler ADM-3A, and I'm not the most CRT-savvy guy around (but I did really enjoy Ian's excellent class at the most recent VCF-E).
Attached is a photo of the issue. If I crank the brightness to clearly see the raster, I can see that the text is actually displaying as dark instead of bright.
Pointers?
Cheers, Garrett
js@sdf.org SDF Public Access UNIX System - http://sdf.lonestar.org
I couldn't find a switch to adjust the video, and actually tried flipping each and power cycling. The switches to the left of the keyboard are all comms parameters (baud rate, parity, stop bits, RS232/current loop, auto newline, half/full duplex). The switches inside the cover on the back have to do with cursor control, destructive space, keyboard lockability, screen clearability, modem control lines, and that sort of thing. The only things remotely display-related are 50/60 hz, and lowercase enable. Again, I flipped each individually and power cycled just to convince myself, and none had any effect on the video. All the switch labels and general layout matched the 1979 manual here (http://vt100.net/lsi/adm3a-mm.pdf), which is consistent with the date codes I found on the CRT etc. I'm starting to suspect, maybe, a transistor on the CRT board? Cheers, Garrett On Tue, 23 May 2017 15:43:24 -0400 william degnan via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
there are the switches under the panel next to the keyboard but also on the main board. You have to read the correct manual to the version of terminal, but most have a label to indicate their function.
On Tue, May 23, 2017 at 1:17 PM, Jim Scheef via vcf-midatlantic < vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
Garrett, IIRCC look for a small plate (maybe a logo) toDOTD7721 the left of the keyboard. Under that plate should be a row of rocker switches one of which should be the solution you seek. Jim
On Sun, 21 May 2017, Garrett Nievin via vcf-midatlantic wrote:
Date: Sun, 21 May 2017 16:07:06 -0400
From: Garrett Nievin via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> To: vcf-midatlantic@lists.vintagecomputerfederation.org Cc: Garrett Nievin <gnievin@silvaire.org> Subject: [vcf-midatlantic] ADM-3A display problem
I'm restoring a Lear Siegler ADM-3A, and I'm not the most CRT-savvy guy around (but I did really enjoy Ian's excellent class at the most recent VCF-E).
Attached is a photo of the issue. If I crank the brightness to clearly see the raster, I can see that the text is actually displaying as dark instead of bright.
Pointers?
Cheers, Garrett
js@sdf.org SDF Public Access UNIX System - http://sdf.lonestar.org
I've been really busy lately - sorry I didn't see this earlier. The picture did not come through - the list doesn't support attachments, could you upload it to imgur or something? IIRC, there isn't a way to invert the video on the ADM3A with a switch, it sounds like you have a failure in the monitor section. It is very possible for a component failure to drive the video negative like that. Check C119 and C112. -Ian On Sun, May 21, 2017 at 4:07 PM, Garrett Nievin via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
I'm restoring a Lear Siegler ADM-3A, and I'm not the most CRT-savvy guy around (but I did really enjoy Ian's excellent class at the most recent VCF-E).
Attached is a photo of the issue. If I crank the brightness to clearly see the raster, I can see that the text is actually displaying as dark instead of bright.
Pointers?
Cheers, Garrett
Hi, Ian! http://imgur.com/a/Z4s7V Here is the image on imgur. I turned the brightness way up, put a loopback on the serial port, and typed all these characters. Everything seems to work correctly except for this negative video drive. I'll definitely check those caps. I replaced the 2.2 uf tantalums just because I had some on hand, but haven't replaced any other caps yet. Thank you! Cheers, Garrett On Fri, 26 May 2017 08:36:31 -0400 Ian Primus via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
I've been really busy lately - sorry I didn't see this earlier. The picture did not come through - the list doesn't support attachments, could you upload it to imgur or something?
IIRC, there isn't a way to invert the video on the ADM3A with a switch, it sounds like you have a failure in the monitor section. It is very possible for a component failure to drive the video negative like that. Check C119 and C112.
-Ian
On Sun, May 21, 2017 at 4:07 PM, Garrett Nievin via vcf-midatlantic <vcf-midatlantic@lists.vintagecomputerfederation.org> wrote:
I'm restoring a Lear Siegler ADM-3A, and I'm not the most CRT-savvy guy around (but I did really enjoy Ian's excellent class at the most recent VCF-E).
Attached is a photo of the issue. If I crank the brightness to clearly see the raster, I can see that the text is actually displaying as dark instead of bright.
Pointers?
Cheers, Garrett
participants (4)
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Garrett Nievin -
Ian Primus -
Jim Scheef -
william degnan