Question Capacitor identification + what blew it?

[giro1991]

Hi

My main question is
1) how likely is the capacitor value the same as the adjacent one seen here?:


What happened:
The following occurred on a wip project build - case open most of the time. After a few weeks off, powered it on, theres was no display... and then burn smell. After a hasty power down I powered again to pinpoint problem part (located the smoke).. then off.

Fried cap is near 12v gpu fan connector.
So i tried with fan removed.
The part doesnt burn with fan gone and display is restored.

I think i can just replace the part but also the fan; I have a spare fan. Same model, so to compare i used multi meter in 20k resistance mode, across gnd + 12v on the fans:

New fan = 9.47
Used fan = .1 (assumed broken?)

Fyi these fans are not the stock one that came with card.
The stock fan = 2.76

From these three measurements it seems the fan that was is snookered … i assume.

The fan was in that config for a year without issue for testing thermals etc. (sff build). The stock gpu fan was swapped out for one with pwm for more control, (iirc so to not be on at idle - fan curve via 12v attenuation couldn’t achieve that) - the pwm line is controlled from motherboard. Is set to 66%.
The 12v draws from existing fan socket on the gpu. Note that the 12v is still varied according to curves stipulated by OS (via utility/app).

Also : I piggybacked another 0.05Amp 4cm noctua fan onto the 12v socket on the card.. so to work in tandem with / in accordance with gpu load.

So one of either three scenarios - ordered likely to least likely IMO is true:

gpu fan went kaput and/or
Capacitor went kaput
The extra fan added to the gpu 12v fan socket exceeded the current limit of the capacitor

Any thoughts?


I obv need order another capacitor, only i cant ID the value hence question 1)

Its a LP radeon 7750, relatively inexpensive but i cant afford to bin it for the mo’ . Hopefully the problem isnt beyond the fan and capacitor.


Im ok with a soldering iron but electronics is so so

 

[artk2219]

Hi

My main question is
1) how likely is the capacitor value the same as the adjacent one seen here?:


What happened:
The following occurred on a wip project build - case open most of the time. After a few weeks off, powered it on, theres was no display... and then burn smell. After a hasty power down I powered again to pinpoint problem part (located the smoke).. then off.

Fried cap is near 12v gpu fan connector.
So i tried with fan removed.
The part doesnt burn with fan gone and display is restored.

I think i can just replace the part but also the fan; I have a spare fan. Same model, so to compare i used multi meter in 20k resistance mode, across gnd + 12v on the fans:

New fan = 9.47
Used fan = .1 (assumed broken?)

Fyi these fans are not the stock one that came with card.
The stock fan = 2.76

From these three measurements it seems the fan that was is snookered … i assume.

The fan was in that config for a year without issue for testing thermals etc. (sff build). The stock gpu fan was swapped out for one with pwm for more control, (iirc so to not be on at idle - fan curve via 12v attenuation couldn’t achieve that) - the pwm line is controlled from motherboard. Is set to 66%.
The 12v draws from existing fan socket on the gpu. Note that the 12v is still varied according to curves stipulated by OS (via utility/app).

Also : I piggybacked another 0.05Amp 4cm noctua fan onto the 12v socket on the card.. so to work in tandem with / in accordance with gpu load.

So one of either three scenarios - ordered likely to least likely IMO is true:

gpu fan went kaput and/or
Capacitor went kaput
The extra fan added to the gpu 12v fan socket exceeded the current limit of the capacitor

Any thoughts?


I obv need order another capacitor, only i cant ID the value hence question 1)

Its a LP radeon 7750, relatively inexpensive but i cant afford to bin it for the mo’ . Hopefully the problem isnt beyond the fan and capacitor.


Im ok with a soldering iron but electronics is so so

The capacitor that blew, the one next to it, and the capacitors in c929 and c930 are all likely the same value. If you can de-solder them, and get the capacitors that haven't blown out of circuit, you should be able to measure their capacitance with a multimeter. As for what blew it, couldn't tell you without examining the board. I would start with removing the blown capacitor, and cleaning up the area around it with IPA to check for board damage. If there isnt any obvious board damage, check the capacitor next to the exploded one for damage, and remove it to test its capacitance, then do the same for c929 and c930. If they're all the same, its likely the capacitor that blew is also the same. I would then follow the traces around from that blow capacitor and look for any other obviously damaged components or shorts. The chip in c901 may also be damaged since it looks like it shares a ground plane, but you don't know until you get in there and look. Fun little electronics project, no clue it its an easy fix though. Where are you located? Is this all going into a small form factor case, and is that why you need a low profile card? Also check your power supply, a bad power supply can cause all of this and more. It may also be worth looking into replacing it with an RX 550 4GB, you can find them for $40 or less on ebay, and its a nice upgrade from the Radeon HD 7750. If you have a decent power supply and room in your case, used RX 470's are also very cheap currently.