VOGONS


First post, by PDAisAok

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I have a missing surface mount capacitor C1427 on the backside of the board underneath the GPU but it has no markings. Is there a parts list available for these old boards?

EDIT: upon further inspection I found one more missing SMD capacitor C296 next to one of the memory chips. I've contacted Nvidia and the response was that there is no technical documentation available. Any other options?

Reply 1 of 3, by havli

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I'm no expert in this matter... but they both seem to used for GPU / RAM input voltage filtering. Assuming your GF4 is using the reference PCB - like this one http://hw-museum.cz/data/vga/pic/MSI_GeForce4_Ti_4200_B.jpg

I think your GF4 should work even without them.

HW museum.cz - my collection of PC hardware

Reply 2 of 3, by PDAisAok

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Thank you for the reply, I have an xfx board

http://www.techwarelabs.com/reviews/video/xfx … hics_gf4ti4200/

I desoldered one of the caps C1422 right next to the missing one, looks like it serves the same function as the missing cap. Used an ESR meter and it showed up as 4 uf with an esr of 0.1. I assume then it's a 4.7uf cap but still not sure on the voltage. I looked at that reference pic and it definitely has the same layout aside from a video encoder chip is included on my board on the right side. If it's simply a filter cap could I jumper the points? I've tested the board with the missing caps and it does not show up in my system

Reply 3 of 3, by shamino

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I have one of these cards (the XFX 64MB model). It doesn't work properly, but it does POST at least.
I still had it stored in a box that was buried. I got it out and scanned the back of the PCB, but I'm not sure how useful this is since it's the same layout as the MSI that havli posted.
I can confirm that C296 and C1427 are definitely supposed to be there. C1427 looks just like C1422, and C296 looks just like C272 and C260.

If it's simply a filter cap could I jumper the points? I've tested the board with the missing caps and it does not show up in my system

Don't jumper the opposing points of a capacitor location - that will create a short circuit.
I would guess one side of C1427 is the GPU Vcore and the other is ground, probably the same with most of the other ceramic caps in that area.
Likewise for C296, I'd assume one side of that cap is the supply voltage for the RAM IC and the other is ground.
These are guesses though, I've never checked it.
I'm not sure if having these caps missing would cause such a total failure of the card, but I suppose it's possible.
All I can suggest is to salvage parts from another card maybe, or try to find someone selling small quantities of these ceramic caps at an acceptable price. I'm feeling doubtful that replacing them will fix your problem so I wouldn't get in to deep with it.

If you're careful, you might be able to probe around for voltages while the card is powered. If you check the ceramics under the RAM and the GPU, you might find appropriate voltages for each of those chips. If you don't, it suggests a problem with the VRMs that are supposed to be powering them.
You could also try checking for voltages at the larger electrolytic caps.
If you try this, put some tape around your positive probe to minimize the chance of shorting anything.

I'm attaching the board scan, just in case it has some value. I had to shrink it down quite a bit though to fit within the 2MB file size limit for attachments. It's still readable at least.
I should restate that the card I scanned here does not work properly. I don't think any parts are missing, but if anything looks wrong, it very well might be wrong.

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