Check MOSFETs, if one of them is shorted it may cause this.
You will have to remove them one by one, since you don't have visual clues as to which one failed.
Another option would ba a failed cap, but since you replaced them I assume they are all fine (?).

bassybeats wrote on 2023-02-26, 08:33:

pins 2 and 3 on side B are shorted to ground.

Its side "A" - AGP detect
+5V rail - on other side. Its connect to small electrolitic near AGP slot and traced via ferrite bead B17 to big capacitor C301 and Mosfeet.
Fuse F1 - its powering DDС in monitor. Its must be AMS1117/LM7805, but its cheap design. That's why is fuse )

shevalier wrote on 2023-02-26, 17:22:

Its side "A" - AGP detect +5V rail - on other side. Its connect to small electrolitic near AGP slot and traced via ferrite bead […]
Show full quote

bassybeats wrote on 2023-02-26, 08:33:

pins 2 and 3 on side B are shorted to ground.

Its side "A" - AGP detect
+5V rail - on other side. Its connect to small electrolitic near AGP slot and traced via ferrite bead B17 to big capacitor C301 and Mosfeet.
Fuse F1 - its powering DDС in monitor. Its must be AMS1117/LM7805, but its cheap design. That's why is fuse )

Ah so Side A is the back side? Fuse is fine and caps are fine, I will check the mosfets and AMS1117 and see what happens.

bassybeats wrote on 2023-02-26, 08:33:

Hey Team, […]
Show full quote

Hey Team,

I am having a tough time figuring out what is wrong with the Radeon R9600 Pro AGP GPU. The PC locks up and won't post with it plugged in ( verified the PC works with another card ).

Going through the 1.5V AGP pinout it seems pins 2 and 3 on side B are shorted to ground. Does anyone have any 'usual suspects' that I should be looking at to see what is shorting the 5v line? Or the next steps in testing should be, the card looks not that bad at all and I have already replaced the caps as they were bulging when I got the card.

Chers

Probably a mere anecdote with no use for what already looks like deep troubleshooting, but to complement, when I got the very same card it refused to post through VGA but after many attempts I decided on a whim to try through DVI with an adapter and it worked. Later switched back to VGA and never had problems since...

bassybeats wrote on 2023-02-26, 20:59:

I will check the mosfets and AMS1117 and see what happens.

Steps to Repair Radeon 9600
First, check the integrity of the GPU crystal, especially at the corners.
Secondly - core power. 1.2-1.3V and memory 2.5-3.0V (depending on design. Memory can be powered by one or two identical regulators - Mem_VDDQ (for I\O) & Mem_VDD)
Third,replace all electrolytic capacitors.

The last step - look for Radeon 9800 Pro/XT))))
Or x850 XTX, but this almost unreal.

shevalier wrote on 2023-02-27, 05:31:

Steps to Repair Radeon 9600 First, check the integrity of the GPU crystal, especially at the corners. Secondly - core power. 1.2 […]
Show full quote

bassybeats wrote on 2023-02-26, 20:59:

I will check the mosfets and AMS1117 and see what happens.

Steps to Repair Radeon 9600
First, check the integrity of the GPU crystal, especially at the corners.
Secondly - core power. 1.2-1.3V and memory 2.5-3.0V (depending on design. Memory can be powered by one or two identical regulators - Mem_VDDQ (for I\O) & Mem_VDD)
Third,replace all electrolytic capacitors.

The last step - look for Radeon 9800 Pro/XT))))
Or x850 XTX, but this almost unreal.

So did some more digging. I was mistaken with the 5V line being shorted, mixed up side A and B on the pin out.

BUT, the two green caps by the fan header are shorted across the pads. So I think that is my issue, I just cant find the short. Could still be the die itself. I'd gladly take a 9800 Pro XT if I could find one without selling a kidney!

bassybeats wrote on 2023-02-27, 08:09:

I just cant find the short. Could still be the die itself.

Resistance of RV350/360 is 9 Ohm on "Diode" range.
This can be confused with a short circuit

bassybeats wrote on 2023-02-27, 08:09:

I'd gladly take a 9800 Pro XT if I could find one without selling a kidney!

like this?