Bulging and Leaking Capacitors







By Tom_Johnson

I submitted the following to repair-feedback@apple.com and to the Apple Product Specialist:

My 20" G5 iMac replaced midplane has failed - Ser# W84394D5PP8 purchased 10/8/04 - still under warranty. My original midplane was replaced 1/20/05.

The System Log shows the same "Graphic Chip Error!"
I ran the Hardware Test CD/Quick Test and received the same video error = 2NVD/1/4:2103.
I then ran the Extended Test and it got to the Logic Board test then reported = Logic Board Error 2GMC/4/15:built-in. The test stopped at this point.
The computer will not restart. I shut it down.
On restart I cannot enter into the Single User Mode to do a fsck - fy test.
The Apple logo screen comes up with the "video jiggles" plus two one-quarter inch vertical bars along the left side of the monitor. After two minutes the fans go to max speed. I shut down the computer and now it will not start up.
I opened up the computer and found capacitors C1009 & C5009 bulging and leaking.
Capacitors C1008, C2208, C2209, C3317, C3332 & C5008 are bulging at the top.
I plugged in a power cord and only got a light for the number one - the other three lights were out. I attempted to startup the computer but it is dead.
The capacitors are manufactured by Nichicon and have an "X" on the top.
I have always had the computer connected to an APC Smart UPS-1000.

Please advise on my course of action to get this computer repaired again !

I do not want a replacement with Nichicon capacitors.

I posted this problem on the Apple iMac G5 Forum:
http://discussions.info.apple.com/webx? ... a31fdd/199

Check out this URL for excellect pictures of the problem:
http://www.oliver-kreuzenbeck.de/iMac_p ... /iMac.html

This has been happening to a couple brands PC motherboards for a couple years now. It happened to my roommate's but I cannot remember what brand capacitor was on that board. This is certainly something Apple doesn't want to see (it might mean very wide reaching problems).

I'm not sure that the capacitors are necessarily at fault.

It seems too much of a coincidence to have a bad bunch in one machine all go bad at once.

Electrolytic capacitors are filled with a conductive liquid which forms one of the electrodes of a capacitor whose dielectric is an ultra-thin layer of aluminium oxide on an aluminium foil that forms the other electrode.
The liquid is water-based.

The "X" stamped in the top face of the aluminium can is an emergency safety valve designed to burst open should the capacitor overheat and literally build up a head of steam. The idea is to go off with a shoosh and not a bang.

Overheating can be caused by several problems:

1) heavy ripple currnent
2) excessive voltage
3) someone or some robot loaded them the wrong way round


The parts come on bandoliers for auto insertion. If someone got a bandolier wrong, all the capacitors of the same type loaded into a number of iMacs could be loaded backwards. They do not like reverse voltage!

Heavy ripple current... not so likely
excessive voltage.... a power supply fault is possible and would do a lot of other damage. That your iMac worked for a while with problems that could be explained by reversed capacitors, where high voltage would have killed things fast, my best guess is reverse-loaded capacitors.

However, the overvoltage problem can be worked the other way, what if wrong parts were loaded.. lower voltage parts than they should be?

I would not worry about Nichicon, they are mainstream manufacturers of aluminium electrolytic capacitors.

By the way, these sorts of parts, if they run hot, lose water content by evaporation and leakage through the rubber seals on their bottom faces. They have a limited lifetime that reduces at higher temperature. Just about everything electronic uses lots of them.

Hope this helps a bit.

I'm still fighting my iMac problem. I thought an SMU reset had done the trick, but booting failed again this morning. Full erase and reload tonight.

Cheers
David

Seeing as the capacitors all came from one company, and it is happening with many different motherboard, I am 99.995% sure that the capacitors are at fault. It's simply bad manufacturing by the company that made them, nothing more, nothing less.

If the capacitors aren't bad, they may be underrated -- voltage wise. I’ve seen it happen back in the 70's when I repaired TVs for GE with a 10" color model they had. Every one we sold came back after x number of hours on it. Same symptom. They would bulge and after awhile would POP.

On the other hand, there is this

I have seen such a problem with capacitors. I remember long ago when one blew almost on my face when I turned the power on. It made quite a bang, followed by a cloud of white fiber.

I was looking inside my iMac, and didn't notice such a problem. I wonder if the power supply is what is causing the problems?

This is my reply from repair-feedback@apple.com:


Envelope-to: tjohnson
Date: Thu, 31 Mar 2005 02:36:50 GMT
X-Authentication-Warning: snowy.corp.apple.com: snrp set sender to sonar@apple.com using -f
To: tjohnson
Subject: Re: Warranty Issues; Follow-up: 8124307
from: warrantyinfo@apple.com
X-WNSpam-Score: 0.2
X-WNSpam-Int: 2

Dear Apple Customer,

Thank you for your email.

Apple does not provide technical support for the iMac G5 via email.

You will find answers to many questions concerning the setup and troubleshooting of your product at <http://www.apple.com/support/imac>. You can also search through thousands of technical articles by entering a few descriptive words in the Search box at <http://www.apple.com/support>.

Alternatively, you may call Apple Technical Support for assistance at 800-APL-CARE seven days a week from 8:00 a.m. to 8:00 p.m. central time. The representative will determine whether a per-incident fee will be associated with the call.

Best regards,

Apple Online Services Support


TC

Customer First Name : Thomas R.
Customer Last Name : Johnson
email : tjohnson
Web Order # :
Support Subject : Warranty Issues
Sub Issue : Incorrect DOP
Comments : My G5 iMac replaced midplane has failed - order# 95896/case# 44807577/Ser# W84394D5PP8 purchased 10/8/04 - still under warranty.

The System Log shows the same "Graphic Chip Error!"

I ran the Hardware Test CD/Quick Test and received the same video error = 2NVD/1/4:2103.

I then ran the Extended Test and it got to the Logic Board test then reported = Logic Board Error 2GMC/4/15:built-in. The test stopped at this point.

The computer will not restart. I shut it down.

On restart I cannot enter into the Single User Mode to do a fsck - fy test.

The Apple logo screen comes up with the "video jiggles" plus two one-quarter inch vertical bars along the left side of the monitor. After two minutes the fans go to max speed. I shut down the computer and now it will not start up.

I opened up the computer and found capacitors C1009 & C5009 bulging and leaking.

Capacitors C1008, C2208, C2209, C3317, C3332 & C5008 are bulging at the top.

I plugged in a power cord and only got a light for the number one - the other three lights were out. I attempted to startup the computer but it is dead.

The capacitors are manufactured by Nichicon and have an "X" on the top.

I have always had the computer connected to an APC Smart UPS-1000.

Please advise on my course of action to get this computer repaired again !

--------------------- Additional Info -------------------------

Serial Number: W84394D5PP8

TrackID: 615641

Looks like you need to call them.

I did call them on Saturday and talked to a Product Specialist - Mykel.
I have forwarded all of my "paper trail" including photos to her.
I'm taking my iMac in for repair today.

wsitze wrote:

"On the other hand, there is this"


Yes, that would explain this sort of thing.


There has been a sort of negative leap-frog going on with some Tantalum capacitor manufacturers. It seems as if they reckoned that their users were de-rating the parts a lot in end designs, so they reduced the working voltage capability of the parts to save on materials. The users found they had to de-rate more to get back to the same reliability and round and round it went.

Thanks for the info!

cheers
David

The Logic Board parts have been very sluggish in coming in lately, most likely because Apple is doing everything they can to correct the manufacturing issue. From what I've seen, the replacement boards have a different/newer manufacturer taking care of the capacitors, and they seem of higher quality. The new generation of iMac also has some subtle re-engineering going on the board, seemingly to take care of those issues as well. First generation woes, combined with an unexpected QC issue from the parts supplier i'm afraid.

I've posted a topic in this Apple discussion group to gather case
numbers of those who had problem with the midplane / logic board,
appreciate your support, thanks. Please check the link below.

http://discussions.info.apple.com/webx? ... @.68b3aed3


From Hood

When I got my LB replaced a month or so ago, I popped the case open and saw that everything looked exactly like the old board. Same brand caps.

Also, according to this http://www.tuaw.com/2005/04/14/when-was-your-mac-born/
my old logic board snW8451156PNY (failed) was born in Shanghai in the 51st week of 2004.
my replacement logic board sn starts with W8435, meaning not only was it built in the same facility, it is older and is also suspected by Apple to have the same problems re: http://www.apple.com/support/imac/repai ... onprogram/