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**willawake** · 06-02-2005, 07:34 AM

Re: High pitched noise from motherboard - symptom of bad caps?

what kinda caps you have on the board? i have seen that board with sanyo and hermei. it would be about time for the hermei to fail.

humming can be from :

- toroid coils on the motherboard
- a failed cap can hum
- smt components on motherboards can hum when the caps are bad
- the psu can hum also for the same reasons

can you pinpoint the source of the hum?

run some http://www.memtest86.com/ and see if you get errors

**bushytails** · 06-02-2005, 10:35 AM

Re: High pitched noise from motherboard - symptom of bad caps?

random guess would be crap caps making the vcore regulator parts whistle...

**drbob** · 06-02-2005, 10:44 AM

Re: High pitched noise from motherboard - symptom of bad caps?

The board is in fact a 7dxr+ if that makes any difference. It's about 3-4 years old and has always been stable

It's a little difficult to make out the capacitor branding without taking the board out of the case, but there appear to be two brands of capacitor on the board. One is green and gold with "K" shaped groves in it's top and says "choyo" on the side. The other is black and gold with and "X" shaped grooves and appears to have "G-LUXON" on the side, but I'm not totally sure of that because of the difficult angle from which I read the branding.

Hope this helps.

**bushytails** · 06-02-2005, 10:50 AM

Re: High pitched noise from motherboard - symptom of bad caps?

Both those (yes, you got them correct) are close to the worst crap caps available...

--Randy

**drbob** · 06-02-2005, 10:57 AM

Re: High pitched noise from motherboard - symptom of bad caps?

I've just found the hall of shame section of the forum. Looks like those brands are bad. Sorry for looking things up better before asking.

**drbob** · 06-02-2005, 11:11 AM

Re: High pitched noise from motherboard - symptom of bad caps?

I'm in the UK - do you recommend anyone to replace the caps over here?

**willawake** · 06-02-2005, 02:14 PM

Re: High pitched noise from motherboard - symptom of bad caps?

I'm in the UK - do you recommend anyone to replace the caps over here?

YOU!!!!!

there are a few UK people who pass by here but not very often if i recall correctly. Wouldnt like to recommend anyone I have only heard about on the net. Bet you could do it though...we'll help. Better take the board out of service before something nasty happens.

anyway read the FAQs and think about it. You can check the prices of the Panasonic FC at RS components http://rswww.com/
in electronic/capacitors/aluminium electrolytic/radial wire ended/[Min Low Impedance FC Series Radial 105°C, Capacitors, 6.3V - 25V (58)]
i'd give you a direct link but they seem to time out most of the time.

if you decide to proceed, lets see a pic of the board and a list of the caps on it, we'll tell you what ones to buy.

**drbob** · 06-02-2005, 11:18 PM

Re: High pitched noise from motherboard - symptom of bad caps?

Ok, I'll give it a go, haven't got much to loose really.

I also have a machine with a soltek kt400-a4c which has been occasionally refusing to post and wake up from standby, reading the forums it looks like that could be due to bad caps too, the same board is in in my house server, so with three boards to recap it starts to look financially viable vs just replacing the board (as long as I don't toast them!)

I've never done any soldering before, maplin in the uk have a good deal on a grounded soldering station for £10, they also sell solder pumps - is this equipment suitable, particularly the pumps, are they pneumatic or mechanical? I'm not sure of the difference since they all seem to use air pressue to suck out the solder. I have a couple of dead boards to practice on (one of which I may not have replaced had I found this site sooner...), so hopefully things will go ok.

Re links to the rs components site, I think that if you remove all the session id stuff from the url, then you get a persistent link, eg: http://rswww.com/cgi-bin/bv/browse/M...toid=-92502691

I'll post a photo of the board later today. Thanks for all your help.

**MD Willington** · 06-03-2005, 10:54 AM

Re: High pitched noise from motherboard - symptom of bad caps?

Soltek will send you replacements for free...

email

lydia@soltek.com.tw.

or

jessica@soltek.com.tw

they will set you up...

I received some panasonic capacitors from them.

MD

**willawake** · 06-03-2005, 11:47 AM

Re: High pitched noise from motherboard - symptom of bad caps?

i have no idea whether that iron is any good. apparently it does 480oC max. you will need about 450oC so it will probably do that. another alternative is to borrow a solder station for a few days. if you are using a new untested iron it would be a good idea to practice on a trash motherboard to see if it is gonna be up to the job. also it is necessary to get some practice of the techniques.

the solder pumps you mentioned are not recommended, they work great but there is danger of sucking out the lead port. the one you can use is called a desoldering bulb, i never got around to trying one. most people here use a dentists tool / dental pick. you can also use a sewing needle. i am using two clamped into an electrical wire connection block so i have one sharp one for getting the hole ready if there is difficulty and the other one is a little smaller than the lead port and has a rounded tip. Other people dont bother to clean the hole and alternately heat up the existing solder and push the cap leads alternately through. i think it is better to clean the hole though. there are so many different techniques, you will find out what suits you

thanks for the rs link tip

MD is right....free caps from soltek yay.....

**drbob** · 06-04-2005, 06:45 AM

Re: High pitched noise from motherboard - symptom of bad caps?

Here are the photos of the gigabyte board. I count 4 of the large purple choyo caps, 8 of the smaller black g-luxon caps and 3 green choyo caps.

The last photo is of one of my soltek boards. I hadn't opened the case since I built it and it seems to definitely have a case of bad caps. How long does it take to receive replacement caps from soltek once they've accepted a request?

As you can see non of the caps on the 7dxr+ look bad externally, I think I'll wait to do the gigabyte board last the soltek boards are trash if I can't fix them.

--
drbob

Attached Files

**willawake** · 06-04-2005, 08:30 AM

Re: High pitched noise from motherboard - symptom of bad caps?

one thing to consider is that caps can visibly fail or they may just become total crap or quite off spec inside but not show visible signs of failure.

so basically the gigabyte boards will have to be done also in the end. although we normally recommend to recap values higher than 1000uf. it is also recommended to recap the 330uf25v g-luxons. you can use similar values or 1000uf16v are great also.

**Exitwound** · 06-22-2005, 03:17 PM

Re: High pitched noise from motherboard - symptom of bad caps?

What a huge coincidence!

I also have a Gigabyte GA-7DXR and the crappy G-Luxon's and Choyo's recently failed on me. More specifically, the two green caps in drbob's fourth picture show bulges and I wouldn't be surprised if the other caps are failing too.

I'm probably going to try to repair it myself with some Panasonic FC's.

**willawake** · 06-23-2005, 02:43 PM

Re: High pitched noise from motherboard - symptom of bad caps?

Hi exitwound

best to recap it while it is still working, then you have the highest chance of successfully repairing the board. if you leave it there is possibility for damage to the board components if a cap fails completely and shorts.

**Exitwound** · 06-25-2005, 07:38 PM

Re: High pitched noise from motherboard - symptom of bad caps?

Originally posted by willawake

Hi exitwound

best to recap it while it is still working, then you have the highest chance of successfully repairing the board. if you leave it there is possibility for damage to the board components if a cap fails completely and shorts.

Yeah, I just decided to put the board out of commission because it was completely unstable. Hopefully I can get my order in on time so that the caps arrive before July 4th.

It's just very saddening to have to downgrade to my much slower (PIII 800) laptop.

**bushytails** · 06-25-2005, 08:54 PM

Re: High pitched noise from motherboard - symptom of bad caps?

your "much slower" laptop is 3 times the speed of mine. no complaining.

(and mine is perfectly usable, so not sure what there is to complain about)

--Randy

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High pitched noise from motherboard - symptom of bad caps?

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