Are these caps bad? *pic*

[agraham]

My mobo (ASUS A8R-MVP bought in mid '06) has been very unstable the last few months. I switched all the components and it's still crashing. I looked at all the caps and they all look good as far as I can tell. Looking at the original video card the caps look bulgy on the top. Is it possible the video card has bad caps and damaged the mobo?

Here's pics of the video card caps (it's an ASUS EN6600 Silencer).
The caps are labelled KZG which according to https://www.badcaps.net/forum/showthread.php?t=425 means they are United Chemicon and should be good quality.





Full rez pics:
http://agraham.ca/shared/ASUS%20EN6600%20Caps%201.JPG
http://agraham.ca/shared/ASUS%20EN6600%20Caps%202.JPG
Thanks,

agraham

[gustie]

Re: Are these caps bad? *pic*

the one in focus in the middle is bulging... so could blow soon ...

[agraham]

Re: Are these caps bad? *pic*

Yeah actually all four of them are bulging equally, you just can't tell because they're out of focus. That, and the respectable brand made me think "well maybe they're supposed to look like that". But I guess not. :-)

[agraham]

Re: Are these caps bad? *pic*

Interesting.. was just reading in the FAQ:

A capacitor has two leads, one of which is the positive and the other is the negative. The negative lead is indicated by a stripe which runs down the side of the capacitor next to that lead. The position of the capacitor on the board is indicated by a white circle stencilled on the board. One half of the circle is coloured white. It is this white hemisphere which indicates the position where to install the negative lead of the capacitor on the board. Pay attention to the position of the original capacitors on the board. We have seen cases where the board stencil was incorrect for one or two capacitors and also boards where the entire stencil was incorrect (Asus TUSL2 and CUSL2-M). Trust the orientation of the original capacitors on the board and not the stencil. It is most likely that the stencil is incorrect instead of the capacitors.

The caps on this video card are backwards from the silkscreen. I wonder if they popped from being installed backwards or if the silkscreen is just wrong?

Newb question: I want to test if they're in backwards with a volt meter. Can just touch the probes to the two solder points for one of the caps on the back of the board? Should I touch neg probe to neg lead (neg on the cap that is, not the silkscreen)? What should I see if they installed correctly (but blown). What should I see if they are installed backwards?

[gustie]

Re: Are these caps bad? *pic*

u wouldnt expect ASUS to be so ropey would u lol

[willawake]

Re: Are these caps bad? *pic*

asus generally install all caps backward ie their silkscreens are wrong who knows why
if caps would be installed with incorrect polarity would blow within some minutes

[PCBONEZ]

Re: Are these caps bad? *pic*

That good vs bad caps list is getting dated. (Old)
New info comes in all the time.

Pretty well known now that KZG don't like heat.
Those are mounted in hot spot right next to heatsink.

.

[Scenic]

Re: Are these caps bad? *pic*

passive cooled graphics card + NCC KZG = no good

they don't like heat at all..

[agraham]

Re: Are these caps bad? *pic*

Oh crappy. My ASUS A8R-MVP mobo is covered with KZGs and some of them are nestled right right up to the heatsink that covers those little regulator chips next to the CPU.

[Scenic]

Re: Are these caps bad? *pic*

well.. but there's some airflow from the CPU Fan...

that graphics card gets (at best) just a little bit of airflow from the front-fans (if any).

and as passive cooled graphics cards usually run quite hot (my GF 7300GT is usually at 50- 70°C) it's no wonder those KZGs said bye bye :/

[tmwalsh]

Re: Are these caps bad? *pic*

Agraham, if you look at the bottom of the mobo, and check the traces, the - side of the cap will generally be soldered to a trace that goes to ground. The + will follow a trace to power of some kind. The ground in most will be LARGE in surface area, and will be connected to the black wire from the power supply. That should verify the connection of the caps.
If all the others have refrained from straining their enclosures, i.e. are flat topped and not leaking, let them ride. Hopefully these 4 (2?) are the culprits. Maybe you should consider an extra fan???
tom