VOGONS


First post, by kenan83

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Hello everyone. I love old systems. I had a 486 system in the 90's. I decided to assemble a new 486 system and started collecting parts. I bought an old case and a Trident tvga 9000b 512kb ISA vga came out of the case. The problem with the card is when I turn on the computer, it starts in color. There is no problem. Then when I reset or restart it, it turns to mono. Likewise, if mono starts, it becomes colored when I reset or reboot. The screen that opens in mono, for example, when I open the doom game, the game becomes colorful. It's totally frustrating. This is the first problem. Secondly, some letters are flashing on the screen. These letters usually flash when I exit a game or close a program and return to "dos". I'm using a CRT as a monitor. Same problem when I plug it into the LCD screen. I tried different slots, I cleaned the dust of the slots. I also cleaned the pins of the card, but nothing changed. I did not understand whether the problem was in the card, the bios or the motherboard. If the problem persists, I'm thinking of replacing the card. I found 1 cheap Cirrus logic g55428 1mb. Should I buy this or 1 mb and above ISA or VLB card advice please. If you could help with this situation, I would greatly appreciate it.

My system;

MOTHERBOARD :FIC 486 PWT
CPU: Cyrix Cx486dx2-v66
RAM: 16MB
VGA: TRIDENT TVGA 512 KB
HDD: SEAGATE IDE 1.2GB ST31276A
I/O : UMC SST284SE
SOUND: ESS 1868F
FDD: EPSON 3.5" 1.44 MB
FDD2: YE DATA YD-380 B 5.25" 1.2 MB
MONITOR: UNİSYS 15" CRT

Reply 1 of 7, by Grzyb

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Problems with 8-bit TVGA9000 based ISA video card

In 2003, I voted in favour of joining the European Union. However, due to recent developments - especially the restrictions on cash usage - I'm hereby withdrawing my support. DOWN WITH THE EU!

Reply 3 of 7, by kenan83

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I solved the problem of the screen switching to mono by disabling the 12th pin of the vga cable. It is now always colored. But my other problem is that I couldn't handle some characters going back and forth on the screen. This problem usually occurs on the dos screen after exiting a game or exiting a program. When you give the cls command in the dos, it becomes normal. There is no problem with the games.

Reply 4 of 7, by Grzyb

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Corrupt memory?
First thing to try is thorough video memory test, using Checkit and X-VESA.

In 2003, I voted in favour of joining the European Union. However, due to recent developments - especially the restrictions on cash usage - I'm hereby withdrawing my support. DOWN WITH THE EU!

Reply 5 of 7, by Deunan

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kenan83 wrote on 2022-03-22, 21:03:

Secondly, some letters are flashing on the screen. These letters usually flash when I exit a game or close a program and return to "dos".

Clean the card and mobo of any dust if you haven't already. A soft (and clean/unused) wall painting brush is a great tool for that purpose. Dust itself is bad, it's even worse when it gets damp due to humidity.
Try different slots for the VGA card, especially the first and last one. If the issue gets considerably better or worse when the card is moved between side slots, you most likely have a mobo with poor ISA termination. Could be a design issue or a weak driver chip. Doesn't really bode all that well for VLB stability. If nothing changes when trying the other slots it could be down to memory on the card itself.

Another thing to try is different BIOS settings. Slower ISA clock or extra bus waitstates might help but it will also reduce the performance.

Reply 6 of 7, by kenan83

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Deunan wrote on 2022-03-24, 11:43:
Clean the card and mobo of any dust if you haven't already. A soft (and clean/unused) wall painting brush is a great tool for th […]
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kenan83 wrote on 2022-03-22, 21:03:

Secondly, some letters are flashing on the screen. These letters usually flash when I exit a game or close a program and return to "dos".

Clean the card and mobo of any dust if you haven't already. A soft (and clean/unused) wall painting brush is a great tool for that purpose. Dust itself is bad, it's even worse when it gets damp due to humidity.
Try different slots for the VGA card, especially the first and last one. If the issue gets considerably better or worse when the card is moved between side slots, you most likely have a mobo with poor ISA termination. Could be a design issue or a weak driver chip. Doesn't really bode all that well for VLB stability. If nothing changes when trying the other slots it could be down to memory on the card itself.

Another thing to try is different BIOS settings. Slower ISA clock or extra bus waitstates might help but it will also reduce the performance.

Reply 7 of 7, by Deunan

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There's different kinds of RAM issues. Broken connection/solder on address lines will cause random glitching. Bad chip - depends on how it died, but usually there's some corruption on the screen but it shouldn't move around, or get progressively worse.

Install Norton Commander 4, use CTRL+O combination to hide/show the panes. Preferably with some text in the background. This will cause both writes and read from card RAM so if doing it a couple of times causes weird colors or flashing letters to appear, you have ISA bus problems. Note that graphic modes might use different timings to access VRAM and the issue might be only visible in text mode (or the opposite).