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1000 TL/2 - Intermittent "blue background" issue

EddieDX4

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I have a bizzarre problem... My 1000 TL/2, very randomly, will change the background color from black to blue. The machine could be sitting there, idling, and bam...blue background (the whole background, including border).

The machine remains fully operational, but if I hit the RESET button the blue remains (even through the POST procedure).

I'm using a CM-11 that I tested with my TX and an HX, and neither cause this behavior with it, so the monitor can be scratched off.

Even if I try to change screen modes (in DOS, or even in BASIC), or if I open a game, the blue remains..

I just upgraded the system to 768k using NEC 41464C-8 chips, but the issue was there before.

Any clues? Is the Tandy Graphics Adapter going bad?

Could it be a conflict with the XT-IDE card I'm using in it?

The issue can happen once every few hours, or a few minutes after using the machine, and sometimes it just switches blue and then back to black within a few seconds... If I power the machine off and back on it's fine, sometimes permanently for that session. This is very odd...
 

southbird

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All I can tell you is that is a function of the video registers. It is possible that something is errantly setting it... or bad RAM of course...
 

EddieDX4

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All I can tell you is that is a function of the video registers. It is possible that something is errantly setting it... or bad RAM of course...

So something is flipping a bit or changing the value of the register that handles the background color? I have the XT-IDE card, plus I just remembered that I also have a Parallel port card set to the default LPT2 address/IRQ5. I don't have the vide sync/IRQ5 jumper enabled on the board, so I'm not sure if that should prevent any conflicts.

Today, however, I haven't experienced this issue. It's quite puzzling.
 

Agent Orange

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Do you have a CGA card that you put in for a test? Even a VGA might make you feel better about your RAM, etc., if it flies for a while.
 

EddieDX4

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Do you have a CGA card that you put in for a test? Even a VGA might make you feel better about your RAM, etc., if it flies for a while.

I have an EGA card I can use... Or the CGA from my Compaq Portable, but that thing is a behemoth (not sure it'll fit in there).

I'm going to test that tonight (EGA likely).

I don't think it is bad RAM because that would cause intermittent issues of other variety, and this seems like a very specific issue. I think it's either a conflict with the XT-IDE and/or Printer adapter, or an issue with the TGA.
 

Agent Orange

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Don't rule out a wonky video cable. A while back I had a cable that got pinched/crushed and rendered some bizzare color combinations.
 

EddieDX4

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Don't rule out a wonky video cable. A while back I had a cable that got pinched/crushed and rendered some bizzare color combinations.

I thought of that, but I don't get the same behavior with different machines on the same monitor, and I also tried moving the cable around a bit and it made no change.
Unless it's the connector on the machine end? But, being how it can change while idling, if so, it could be heat related.
 

EddieDX4

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Don't rule out a wonky video cable. A while back I had a cable that got pinched/crushed and rendered some bizzare color combinations.

Finally had an "ah ha!" moment... It is indeed the monitor's cable, but not on the connector end but on the monitor end (fixed end).... It finally happened while I was testing with an EGA card, and I kept jiggling the cable until I got to the monitor end and voila! The blue went away immediately, then I made it come back.

It's pretty much gone now that I've sort of "pulled" the cable slightly right. This is an old CM-11, and it's amazing that's the only issue it's exhibited after all of this years. It's also a rather simple fix.

Thanks for this suggestion, which at some point I was almost ready to rule out. At least I know my TL/2 is sound. :)

By the way, I've decided to permanently leave my Everex EV 659A EGA card in there... Reason being that pretty much every DOS game that supported Tandy 16 color graphics also supported EGA, but the inverse is not true in many games that support EGA. I'm having better luck with some older games.

Also, some of the abandonware site copies of games strip the non-EGA files (Castlevania being a prime example). Luckily, the TD.DRV (Tandy sound) file is easy to locate in forums, so I've got Castlevania running on EGA with Tandy sound... :)

I can also play Thexder 2 in EGA 640x200 16 color mode! When I saw this played in that mode in a YouTube video, it looked like crap (standard Tandy 16 color mode looked better), but on a real RGB monitor it actually looks better. I think they took advantage of the coarser rectangular RGB monitor pixels, similar to the trickery done over composite monitors/TV sets with the older CGA "16 color" modes in some games.

I'm happy with the setup. The only thing it does away with is the 225 lines mode in DOS. Woopdie doo...
 

Agent Orange

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FWIW, Tandy used to market video cables with 'flying leads' and assorted connectors. Whether or not RS still stocks that sort of thing is another item. I sold my old EGA monitor to a fellow at work, who's 'old auntie' needed a pc to browse the IE. About ten years later he dropped it off at my office and wanted to know if I'd like to have it back or should he just pitch it. I took it back, but someone had stepped on the connector and it was cracked good. I replaced the cable and connector with the RS stuff. We're talking 2001-02 - so that's quite a while.
 

EddieDX4

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FWIW, Tandy used to market video cables with 'flying leads' and assorted connectors. Whether or not RS still stocks that sort of thing is another item. I sold my old EGA monitor to a fellow at work, who's 'old auntie' needed a pc to browse the IE. About ten years later he dropped it off at my office and wanted to know if I'd like to have it back or should he just pitch it. I took it back, but someone had stepped on the connector and it was cracked good. I replaced the cable and connector with the RS stuff. We're talking 2001-02 - so that's quite a while.

Good to know... It seems RS has kept a lot of the same parts for many years, so they may still sell this (via catalog, perhaps). Either way, it's an easy fix even if I have to open up the monitor to replace the cable internally. I'm just glad it's not the TGA in my TL/2.

I finally paired up my TL/2 with my industrial IBM EGA monitor. I know it's not exactly a match made in heaven, looks wise, but it has opened up many doors for more games (and some that look MUCH better on a true EGA monitor with its capability of displaying extra colors/intensities with an EGA adapter). It's amazing how I never really noticed that much before until I did the straight comparo between my CM-11 connected to EGA, and the IBM EGA monitor.

My CM-11 will be used with my TX and my HX machines (the latter, if I ever find the appropriate monitor platform that Tandy made for the EX/HX machines).
 

Agent Orange

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Golly gee-whiz and gosh darn it too! With all this buzz lately about EGA, I wish I would have kept my monitor for my 1000SX. I still have the BOCA EGA card, but lost/misplaced the 5.25 floppy that came with it. You could program the system fonts in that card. BOCA is still in business but they've moved on and don't have time for crusty old archives. Good luck with your monitor problem.
 

kb2syd

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I have:
EGABOCA.ZIP 8173 8/01/90 EGA by Boca Software 1.05
MULTIEGA.ZIP 117736 1/04/80 MultiEga Software 1.02
in the boca mirror on my ftp site. Any of these useful?

I take it back. They didn't keep file area 12. Sorry...
 

Agent Orange

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About a year ago I poured over that BOCA site and saw where they whacked the good stuff. I got tired of looking on the net for that EGA disk. When I retired 3 1/2 years ago, I lost a tub full of 5.25 disks and that was one them. Maybe someone out there still has it.
 
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