VOGONS


First post, by Jackhead

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I bought a VLB Graphics card as non working and trying to repair it. First at all i checked the 5v line on the ISA and VLB . No short.
After that i pluged the card into my 486 but i got no signal out.
I notice the VGA plug was really bad and replaced it. I also replaced the clock quarz.
There was a damage on the 5v gnd pins on the isa line, i add some solder for better connection.
Any idea what i can check next?

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Last edited by Jackhead on 2025-03-21, 15:48. Edited 2 times in total.

Dos 6.22: Asus VL/I-486SV2GX4 Rev 2.0 1Mb L2 - A5x86 X5 P75 - 64MB - AHA-2842A VLB - ET4000W32P VLB - CT2230 - GUS ACE - MPU-401AT with YucatanFX
Win98SE: Asus P5K-WS - E8600 @ 4,5GHz - Strange God Voodoo 5 6000 PCI-X - 2GB DDR2 1066 - Audigy 2 ZS

Reply 1 of 9, by zb10948

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Does the computer work with the card in? Normal beep and POST?

Reply 2 of 9, by Jackhead

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no it wont boot at all. No beep, nothing. My CRT say no Signal.

Dos 6.22: Asus VL/I-486SV2GX4 Rev 2.0 1Mb L2 - A5x86 X5 P75 - 64MB - AHA-2842A VLB - ET4000W32P VLB - CT2230 - GUS ACE - MPU-401AT with YucatanFX
Win98SE: Asus P5K-WS - E8600 @ 4,5GHz - Strange God Voodoo 5 6000 PCI-X - 2GB DDR2 1066 - Audigy 2 ZS

Reply 3 of 9, by zb10948

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Does the computer start POSTing if you remove the video bios eprom?

Reply 4 of 9, by Jackhead

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zb10948 wrote on 2025-03-21, 16:09:

Does the computer start POSTing if you remove the video bios eprom?

i removed the bios chip, still no posting.

Dos 6.22: Asus VL/I-486SV2GX4 Rev 2.0 1Mb L2 - A5x86 X5 P75 - 64MB - AHA-2842A VLB - ET4000W32P VLB - CT2230 - GUS ACE - MPU-401AT with YucatanFX
Win98SE: Asus P5K-WS - E8600 @ 4,5GHz - Strange God Voodoo 5 6000 PCI-X - 2GB DDR2 1066 - Audigy 2 ZS

Reply 5 of 9, by zb10948

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Ok, so in direction of electrical problem.
Have you done a thorough visual inspection? It appears to me, on a picture, there is via damage around the C36 label just above the 14.31 MHz crystal

Reply 6 of 9, by Jackhead

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good eye, i checked it but lines are ok , only flux or dirt.
i dont see any damage under my scope.
considering the two damaged isa pins im atm thinking about the video memory glock generator the ICS2494AN.
But i dont know if that chip can did result the problem.

Dos 6.22: Asus VL/I-486SV2GX4 Rev 2.0 1Mb L2 - A5x86 X5 P75 - 64MB - AHA-2842A VLB - ET4000W32P VLB - CT2230 - GUS ACE - MPU-401AT with YucatanFX
Win98SE: Asus P5K-WS - E8600 @ 4,5GHz - Strange God Voodoo 5 6000 PCI-X - 2GB DDR2 1066 - Audigy 2 ZS

Reply 7 of 9, by zb10948

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The ISA contacts might've been just worn out by janking the card out of the slot with pivot being in the middle.

Also there are some reference designs in this document
http://www.bitsavers.org/components/tsengLabs … roller_1990.pdf

But it seems to be based on 4 discreete crystals and not a single clockgen.

Reply 8 of 9, by Jackhead

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i found the issue! Some short on the GPU lines. reflowed and card is back to life!

The attachment IMG_8224.jpeg is no longer available

Dos 6.22: Asus VL/I-486SV2GX4 Rev 2.0 1Mb L2 - A5x86 X5 P75 - 64MB - AHA-2842A VLB - ET4000W32P VLB - CT2230 - GUS ACE - MPU-401AT with YucatanFX
Win98SE: Asus P5K-WS - E8600 @ 4,5GHz - Strange God Voodoo 5 6000 PCI-X - 2GB DDR2 1066 - Audigy 2 ZS

Reply 9 of 9, by zb10948

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Great!