Re: ASUS A7N8X-E Deluxe leaking United Chemi-Con KZG

The board ready for work.

Close-up of bad caps.

The five output caps after removal.

It looks like this.


I must say it was hard! I thought it would be easier. After doing that I don't have very high hopes that it will work. I will try it later, but I expect massive shorts.
Also it really needs a lot of heat. I worked all the time at 450C because that was the max on my soldering iron, but I would have used 500+C if I could.

Re: ASUS A7N8X-E Deluxe leaking United Chemi-Con KZG

I'm going to start working on it tomorrow I wish. Here are some pics.

The board as I took it out of the case, after dusting.


Faulty KZGs on the VRM output.


Notice that the second cap leaked a lot from the bottom.
There is a large bubble of this thing that got dry on the board. (How do you remove that?) You can see that the input caps look perfect.



New capacitors. They are large! I also ordered some polymers to try them. I don't...

Re: ASUS A7N8X-E Deluxe leaking United Chemi-Con KZG

It's an L6917BD from ST Microelectronics.
[URL=http://www.ortodoxism.ro/datasheets/stmicroelectronics/8162.pdf]Datasheet[/URL]Re: ASUS A7N8X-E Deluxe leaking United Chemi-Con KZG

It's an L6917BD from ST Microelectronics.
[URL=http://www.ortodoxism.ro/datasheets/stmicroelectronics/8162.pdf]Datasheet[/URL]

Re: ASUS A7N8X-E Deluxe leaking United Chemi-Con KZG



I did compare with different VRM designs too. As you said, newer boards with solid polymers on vCore have more caps. But also I noticed most of them have 3 or 4 phases. Probably this allows for a lower C value. My board is of an older design (VRM input on +5V!!) and has 2 phases. So I'll have to try to know if it works with PSA.

I did see the 4V caps too and they look interesting. I was just a bit scared, because as I understood the circuit there can sometime be spikes way higher than the target...

Re: ASUS A7N8X-E Deluxe leaking United Chemi-Con KZG



I don't think there is any problem with MOSFET cooling. If you look at the board's picture, the MOSFETs are rather large. Also I do not like MOSFET heatsinks. I think all of the cooling should be done at the PCB level, as the chip is designed with a large metal contact under it where heat can escape. Also the chips do not feel very hot when I touch them. However, I must say that my CPU (Athlon XP-M 2500+) is overclocked from 1.87GHz to 2.4GHz, and I run it 24/7 because of rosetta@home.
The problem with heat...

Re: ASUS A7N8X-E Deluxe leaking United Chemi-Con KZG

I think I will go with some United Chemi-Con PSA Series solid polymer capacitors.

Here are the specs:
680uF, 6.3V
7.0 mOhm ESR
5860 Rated ripple current (mArms/105c, 100kHz)
Manufacturer Part Number APSA6R3ELL681MJB5S
Digi-Key Part Number 565-3065-ND

So they seem nice, but the capacitance is quite lower than what I originally had. What are the dangers with this?

Also another option that I thought of is to use theses PSA for the secondary side, and...

Re: ASUS A7N8X-E Deluxe leaking United Chemi-Con KZG

Yeah I meant 10mm can diameter, pin to pin is more like 5mm.
What's so good about the Panasonic FM? Some people told me not to put 12.5mm in a 10mm spot.

Yeah I think I can order from Digikey. I went to that site and also found "Panasonic NHG"s and "Nichicon VZ"s, are these bad capacitors?

On that picture you posted, the capacitors that are dead are the complete row of five large capacitors.
I think they may have died earlier than the other 3 because they are closer...

Hi,
I purchased an ASUS A7N8X-E Deluxe 3½ years ago and have been using it 24/7 since then. The United Chemi-Con KZG capacitors are all dead on the secondary side of the CPU's VRM. They are all poped on both extremities. The primary side of the VRM also uses theses caps, but they seem fine.

What should I replace them with? I thought maybe I should replace them with the same kind (maybe it's just a bad batch), or is that a stupid choice? Is there some wide-spread problem with this kind of caps, or is this not likely to happen again?

Should I also replace the...