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Faulty Radeon 9800 Pro

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First post, by Retronerd878

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I have a Radeon 9800 Pro that doesn't display at all and motherboard outputs multiples beeps as video card is missing.

The electrolytics cap near the molex connector in missing. Pictures online suggest it's a 180 uF cap.
Also the heatsink from the nearby mosfet is missing as well. The mosfet is warm when turning on the card but not hot.
Voltage measurements as suggested by tehsiggi:
VDDC - Around 1.66V - Measured 1.68V
MVDDC - Around 2.9V - Measured 2.7V
VTT - Around 1.45V - Measured 1.4V
MVDDQ - Around 2.7V - Measured 2.65V

Is that cap that important? Is that the problem, or should I be looking somewhere else?

Reply 1 of 12, by tehsiggi

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The 180µF cap is the input bulk cap for the 12V_EXT rail. It's needed by the MVDDC regulator to properly function. Not having it means the switching regulator needs to rely on the impedance of the power rail coming from the PSU to properly function. That can work. I wouldn't expect it to cause the card to be not recognized. From the pictures some parts of it look "dirty" - like there is corrosion on pads or something?

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AGP Power monitor - diagnostic hardware tool
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Reply 2 of 12, by Retronerd878

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Doesn't look that bad. I definitely seen worse. The fan is completely dead and the top part with blades is detached from the motor as the motor is filled with green corrosion. This card has definitely seen its fair share of moisture.

Reply 3 of 12, by Retronerd878

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I actually had a 180 cap and after i installed it nothing changed. Any ideas what to do next?
Could it be that the bios is broken? I do have a bios programmer, though I have no idea which chip is the bios. Or maybe there is way to program it using another video card for display?
I also have an ultrasonic cleaner. Think that will make a difference? Maybe there is some corrosion under the GPU and it will help.
Would like to try the bios thing first, If i clean it, It's nice to clean the flux residue from the bios chip removal as well.

Reply 4 of 12, by tehsiggi

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Bios is U80 on the backside of the card.

If you have a PCI card at hand, you can boot with that one as your primary and have the 9800Pro alongside it. Iirc "newer" versions (like 3.60) of ATIFlash should be able to detect non primary cards as well, that way you could easily get a bios dump of the card.

AGP Card Real Power Consumption
AGP Power monitor - diagnostic hardware tool
Graphics card repair collection

Reply 5 of 12, by shevalier

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Check "external power" (molex) circuit detection

Aopen MX3S, PIII-S Tualatin 1133, Radeon 9800Pro@XT BIOS, Audigy 4 SB0610
JetWay K8T8AS, Athlon DH-E6 3000+, Radeon HD2600Pro AGP, Audigy 2 Value SB0400
Gigabyte Ga-k8n51gmf, Turion64 ML-30@2.2GHz , Radeon X800GTO PL16, Diamond monster sound MX300

Reply 6 of 12, by Retronerd878

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ATIflash detects the card but i can't flash the bios. Am I doing something wrong?

Reply 7 of 12, by shevalier

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"atiflash -unlockrom 0"

https://archive.techarp.com/show26c2.html?fileID=22

https://web.archive.org/web/20050307111746/ht … amsung256MB.bin
https://web.archive.org/web/20050307112159/ht … amsung128MB.bin

Last edited by shevalier on 2026-05-11, 10:33. Edited 2 times in total.

Aopen MX3S, PIII-S Tualatin 1133, Radeon 9800Pro@XT BIOS, Audigy 4 SB0610
JetWay K8T8AS, Athlon DH-E6 3000+, Radeon HD2600Pro AGP, Audigy 2 Value SB0400
Gigabyte Ga-k8n51gmf, Turion64 ML-30@2.2GHz , Radeon X800GTO PL16, Diamond monster sound MX300

Reply 9 of 12, by Retronerd878

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OK, I got a bios rom with samsung memory.
The command unlockrom doesn't work so i got a newer version of ATIflash.

With the new version the command returns:
Failed to read ROM.

Also, when I try to program the bios with the newer version the computer hangs.

I would take the chip off but it's not clear to me what adapter i need to convert SOIC-8 to DIP, so i can use the programmer.

Reply 10 of 12, by shevalier

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Retronerd878 wrote on Today, 11:33:
OK, I got a bios rom with samsung memory. The command unlockrom doesn't work so i got a newer version of ATIflash. […]
Show full quote

OK, I got a bios rom with samsung memory.
The command unlockrom doesn't work so i got a newer version of ATIflash.

With the new version the command returns:
Failed to read ROM.

Also, when I try to program the bios with the newer version the computer hangs.

I would take the chip off but it's not clear to me what adapter i need to convert SOIC-8 to DIP, so i can use the programmer.

SOIC8 SOP8 to DIP8 EZ Programmer Adapter Socket Converter Module With 150mil
https://www.amazon.in/Menton-SOP8-DIP8-SOIC-A … r/dp/B073TYXLTR
https://www.amazon.com/HiLetgo-Programmer-Ada … r/dp/B01HTC5DKS
https://www.amazon.in/SOIC8-SOP8-Programmer-A … r/dp/B0DPR32S4X
150 Mil

Aopen MX3S, PIII-S Tualatin 1133, Radeon 9800Pro@XT BIOS, Audigy 4 SB0610
JetWay K8T8AS, Athlon DH-E6 3000+, Radeon HD2600Pro AGP, Audigy 2 Value SB0400
Gigabyte Ga-k8n51gmf, Turion64 ML-30@2.2GHz , Radeon X800GTO PL16, Diamond monster sound MX300

Reply 11 of 12, by Retronerd878

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I actually got one of those adapters in the box. Took the chip out and reflash the chip successfully.
The card behaves the same way. No output and post code beeps.
However, if I use a PCI card, when I get to windows, the card is detected in device manager.

Reply 12 of 12, by shevalier

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Retronerd878 wrote on Today, 13:38:

I actually got one of those adapters in the box. Took the chip out and reflash the chip successfully.
The card behaves the same way. No output and post code beeps.
However, if I use a PCI card, when I get to windows, the card is detected in device manager.

Some graphics cards do not display any messages if the external Molex power connector is not connected.
Check the signal lines from the Molex connector.
It’s something like a ground pin that’s connected not to grownd but to the base of a transistor or some kind of little logic chip.
Perhaps @tehsiggi has a suitable circuit diagram.

Aopen MX3S, PIII-S Tualatin 1133, Radeon 9800Pro@XT BIOS, Audigy 4 SB0610
JetWay K8T8AS, Athlon DH-E6 3000+, Radeon HD2600Pro AGP, Audigy 2 Value SB0400
Gigabyte Ga-k8n51gmf, Turion64 ML-30@2.2GHz , Radeon X800GTO PL16, Diamond monster sound MX300