Asus A7N8X-E don't start after recapping

[bitok]

Hello,
It is my first post on this forum. Till now i only fallow some topic.
Yesterday I decided to recap three 3300uf/6,3V Nippon KZG capacitors (form one branch of vrm) despite mobo works stable. I replaced blown caps for MCZ Rubbies. Recapping went without any problems, soldering pads looks relay fine but board didn't start. only collers of CPU and GPU are working).
Could You snuggest me what went bad? May be MCZ is to good and i have to use MBZ series of Rubbies (MCZ have too low ESR than original KZG). I dont wont to solder and desolder to many times before i'm sure of reason why mobo don't start.
Thank i advance for help

The mobo looks just like in this post:

https://www.badcaps.net/forum/showth...?t=5017&page=2

[PCBONEZ]

Re: Asus A7N8X-E don't start after recapping

Reset your CMOS

...... After you replace the rest oh the KZG's.

[bitok]

Re: Asus A7N8X-E don't start after recapping

I reseted bios. It changed nothing.

KZGs was repleace form one of VRM line. I marked them on picture:



Does replace rest 5 of KZGs form second branch of VRM change something?
I can't understand relation between replacing all KZGs and starting board, however before replacing this tree among one was blowed board was starting.
Could you explain

[PCBONEZ]

Re: Asus A7N8X-E don't start after recapping

KZG's fail without bloating at all.
You had some bad KZG.... the rest are most likely bad too.

Take out the battery when you are changing caps to reduce the chance of zapping your BIOS.

Looks like you may have some Nichicon HM on other parts of the board.
If the dates on them are from 2001-2004 they are bad too. [Factory screw-up]
Dates on those are like "H0233" -- That would be week 33 of 2002.
- I dunno what the H means but it's usually an H or an A.

[Uranium-235]

Re: Asus A7N8X-E don't start after recapping

keep in mind, with a lot of asus boards the circut marking for caps is reverse. don't put the negative side of the cap on the full half moon

[bitok]

Re: Asus A7N8X-E don't start after recapping

Hello,
Attached is not real but for sure there are KZG.
My english isn't so good and I don't understand what mean "zapping BIOS" - something like destroy or damage? But for sure I didn't take out battery.

[yyonline]

Re: Asus A7N8X-E don't start after recapping

Was it working before you attempted to repair it? If it was, double check all your connections and cables. Try running the board outside of the case to eliminate the possibility of the case or some object causing a short. If you removed the cpu heatsink, double check that it is installed correctly.

[mockingbird]

Re: Asus A7N8X-E don't start after recapping

Which language do you speak?

Zapping BIOS means near where the coin-cell battery is, there should be a jumper, or markings for a jumper, which you should short to erase the data in the CMOS.

Also, you should replace any capacitor which is OST/Teapo or KZG. Not just the capacitors near the CPU.

[bitok]

Re: Asus A7N8X-E don't start after recapping

Hi
The mobo works before recapping. I checked all connection after recapping, there is no short. I tryed to running it only with CPU, RAM and Graphics card outside of case without positive result.
I try to comprehend what went wrong and in my opinion I destroy bios (if it is possible - the battery was on board), or ESR of assembled capacitors is too low KZG has 0,012 and MCZ 0,009 and delays the output signal, and the additional delay leads to another kind of instability and the board won't post boot.
Have You experience with this board after recapping to lower ESR then was before? I found only two case when recapping A7N8X was successful. In both cases the board working with Rubbies MBZ.

[PCBONEZ]

Re: Asus A7N8X-E don't start after recapping

Zapping = Static Damage.
It is a slang expression.

Replacing KZG with MCZ should be fine.

What Uranium-235 is saying is that Asus marks the + and - backwards from what is standard.
-- See pic

Your attachments didn't attach.
-- See other pics.

[bitok]

Re: Asus A7N8X-E don't start after recapping

[QUOTE=bitok;157584]Hi
The mobo works before recapping. I checked all connection after recapping, there is no short. I tryed to running it only with CPU, RAM and Graphics card outside of case without positive result.
I try to comprehend what went wrong and in my opinion I destroy bios (if it is possible - the battery was on board), or ESR of assembled capacitors is too low KZG has 0,012 and MCZ 0,009 and delays the output signal, and the additional delay leads to another kind of instability and the board won't post boot.
Have You experience with this board after recapping to lower ESR then was before? I found only two case when recapping A7N8X was successful. In both cases the board working with Rubbies MBZ.

[bitok]

Re: Asus A7N8X-E don't start after recapping

Hi,
Thanks for all suggestions.
Now motherboard is starting. Probably problem was with zapping bios. I took out battery and move the cap on pins for CLRT and keep it in this position for half minute, after that mobo started.
But I'm afraid of recapping rest of KZG. Should i recap all or use board with recapping 3 of 8 KZGs?

[Uranium-235]

Re: Asus A7N8X-E don't start after recapping

you've gone this far, so why not, just remember they're reverse

[PCBONEZ]

Re: Asus A7N8X-E don't start after recapping

Remove the CMOS battery and replace the rest of the KZG.

You already had some KZG completely fail.
The rest of the KZGs are not far behind. [Won't last much longer.]

You are doing very well.
Don't get discouraged now, you are almost done.

[bitok]

Re: Asus A7N8X-E don't start after recapping

Should I replace two KZG 820uF 6,3V near DIMM slots to?

[PCBONEZ]

Re: Asus A7N8X-E don't start after recapping

Yes.
I would replace any KZG that are 6.3mm diameter or larger.
[Data sheet only shows 8 & 10 mm sizes but I've seen smaller ones.]

If you can't find 820uF then 1000uF should be fine there.

KZG not only fail without bloating, they have a habit of failing suddenly.
System works fine one day and the next day it just won't boot.
That has happened to me -personally- twice with KZG and many other people have reported similar experiences.
.

[bitok]

Re: Asus A7N8X-E don't start after recapping

Hi,
Yesterday i recapped rest of KZG on my A7N8X-E. Five 3300uF and two 820uF near dimm. Now mobo working great and is stable as rock. I can run CPU on higher FSB then before without loosing stability.
Thanks all for help, and double thanks for PCBONEZ.

[PCBONEZ]

Re: Asus A7N8X-E don't start after recapping

Congrats!

[Fud]

Re: Asus A7N8X-E don't start after recapping

keep in mind, with a lot of asus boards the circut marking for caps is reverse. don't put the negative side of the cap on the full half moon

I'm just about to do an asus board as soon as the parts come in a couple of days from now, I didn't know the polarity is reversed on them.

How about just making sure the stripe on the cap that only runs down one side is over the black part like the old ones to save confusion?

[PCBONEZ]

Re: Asus A7N8X-E don't start after recapping

What is reversed on Asus are the 1/2 circle marks on the board.
There is no official standard for that marking but about everyone except Asus marks them the other way.
-
When you recap ANYTHING make a cap-map before you start removing caps.
Mark the polarities of the originals [as well as what goes there] right on the map.
[I take a snap-shot and print it big, but you can just draw it out too.]
-
There are other good reasons to make a cap-map.
- If your project gets interrupted while you have a bunch of caps out, all the holes [even the 'spare' holes] look the same when you come back to it.
- Sometimes there are random errors in the polarity markings [on any kind of board] such that one or a few caps are marked backwards from the rest on -that- board.
- Not so much on motherboards but, once in a while you will run into bipolar caps which don't have a polarity at all. By making a map you won't make the mistake of installing a polarized caps where bipolar caps were. [And you won't waste time trying to figure out which way the 'missing' polarity mark [that actually shouldn't be there] is supposed to go.]
-
-
People come in here -all the time- with "I have a bunch of caps out and I dunno where they go!".
Sometimes someone can help them but other times not.
- The ONLY time I ever skip making a map is when I have more than one of the same board, in which case the other board IS the cap-map, so I'm not really skipping using a cap-map at all. I'm just not printing one.
.