What kind of capacitors are these?

[dicky96]

Hi guys
This question may have gone unnoticed on a repair thread I have here in another section

What sort of capacitors are these black plastic ones? I broke one and need a replacement.

[budm]

Tantalum cap. What is printed on top?

[dicky96]

Thanks budm

the are marked 470 and 2.5 or 3.0 if I remember without looking again. They are on Vcore on a GTX780ti so either value would work.

I had no problem working out the value. just what they are.. I always thought Tants were blue or yellow things

With your advice I can now find what I need. I've ordered some. Cheers

https://www.aliexpress.com/wholesale...alum+capacitor

[stj]

tants are yellow or black - usually with white writing,
polymers are black,<< they could be polymers
neobium are orange

[redwire]

VRM for a mobo or graphics card, I would say they must be SMT solid polymer parts for their low ESR. Might be hybrid tantalum/polymer.
Note the pc board has dual footprints to use can types or rectangular moulded parts. It's whatever is cheapest at the time of production.

[Uranium-235]

something is missing, I can't put my finger on it...oh wait, the gpu

[stj]

it wouldnt have worked anyway, there is gray paste all over the ram and power circuits.
that shit is capacitive!

[dicky96]

Oh should have explained but it was on my other thread here so I didn't

Short version (pun intended)

I had a short on Vcore

I used my ESR meter to figure out which side of the VRM inductors was the short because my multimeter could not tell difference either side of the coils but to the ESR meter it was obvious it was load side

I then removed all these capacitors (most were these black ones but four were solid aluminium electrolytics) Unfortunately I broke one of the black ones in the process.

It made no difference to the short anyway so then I removed the GPU thinking that was short - but still it made no difference, which surprised me.

I then used my microscope and found a MLCC on Vcore that looked distressed and removed it. The MLCC actually was short, but Vcore only went from 0.5 ohm to 1 ohm

Next I used my bench PSU to put 1.2V into Vcore at a good 3 Amps and found another MLCC getting very hot

I removed that and the short had gone

Now I just need to to reball the GPU (have ordered a stencil), solder it and replace the black tantalum capacitor I broke, hence this thread (also ordered some) and with a bit of luck I will have a good working GTX 780ti graphics card

Simples really.