Router and Power Supply information - Bad Capacitors

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redhawk0
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PostPosted: Sun Aug 23, 2009 12:45    Post subject: Router and Power Supply information - Bad Capacitors Reply with quote
Subject changed to reflect a wider problem. (multiple make/model/power bricks)


Hi guys,

I finally received a donated brick of an Asus WL500W (thanx rosswil)

I have some information for you guys that WILL be of interest.

Symptoms of this bricked unit:

1 - LAN 1-4 and WAN LED's come on solid...no Pwr or Air LED

2 - Serial communication would work intermittently.

3 - Unit would flash both dd-wrt and Asus firmware...but it would freeze after it finished loading....power cycle would not produce any results.


Here is what I found.

1 - The capacitors that regulate noise from the input power were all bad.

There are 3 major polarized electrolytic capacitors. one 1000uF, and two 470uF capacitors. There have been quite a few bad capacitors manufactured over the last 3-8 years (do a google search if you don't believe me)....these capacitors will show the top of the canister being bulged or sometimes leaking electrolytic....this router had bulging (domed top) capacitors....they should be perfectly flat.

2 - The power brick was bad.

Unplugged from the unit the output of the 5V@2.5A brick was 5.294V....but when plugged in...the voltage supplied to the motherboard was 2.959V This is way to low to even run Serial (+3.3v) reliably.

After replacing the capacitors with good caps (from an old PC motherboard) and changing out the power pack (Linksys 5V@2.5A) this router runs great.

Currently loaded and working wonderfully is BS 12672_mega_generic.bin file.

redhawk



IMG_0027.jpg
 Description:
Bad capacitors...notice the domed tops...they should be perfectly flat.
one 16V@1000uF, and two 16V@470uF
 Filesize:  401.32 KB
 Viewed:  32754 Time(s)

IMG_0027.jpg



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I currently test dd-wrt on Asus, Buffalo, Linksys, and Netgear. Too many to list.

Looking for more test units (newer models) for the project...got a brick?...PM me to make a donation. (USA) A donation is not a debricking service....it is a way to "Give back" to the dd-wrt project.

I do NOT provide personal assistance through chat or phone....so please don't ask.


Last edited by redhawk0 on Wed Aug 26, 2009 12:01; edited 2 times in total
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thx-1138
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PostPosted: Sun Aug 23, 2009 13:20    Post subject: Reply with quote
Hello Redhawk0,

Great finding! I will physically inspect my Asus WL-500g Premium to look out for the same issue. It makes sense that unreliability will drop into a device if it has bad capacitors; I have seen it many times with personal computers but never on routers. Thank you for sharing this important information with all of us.
redhawk0
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PostPosted: Sun Aug 23, 2009 13:30    Post subject: Reply with quote
Agreed...this is the first router I found with bad caps. Most problems have been seen on computer motherboards...I have purchased many Dell's down through the years and just this decade, have I seen the cap problem. Google search reveals that this is a widespread problem so it doesn't surprise me too much that some made there way into the router market. Once they manufactures were made aware of the problem, this problem was remedied...however, there are still many devices out in service that have bad caps that people are unaware of...if one Asus has the problem...I'll bet there are quite a few others too.

If I get a chance to break open the power brick...I'll bet there are bad caps in it too.

redhawk

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I currently test dd-wrt on Asus, Buffalo, Linksys, and Netgear. Too many to list.

Looking for more test units (newer models) for the project...got a brick?...PM me to make a donation. (USA) A donation is not a debricking service....it is a way to "Give back" to the dd-wrt project.

I do NOT provide personal assistance through chat or phone....so please don't ask.
thx-1138
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PostPosted: Sun Aug 23, 2009 13:36    Post subject: Reply with quote
Yes, I have been on the same road with Dell Optiplex GX2xx series workstations. Back in 2005 I had to replace 80% of all failing motherboards because of this same issue. The power brick on the Asus routers are sealed so by opening them will just destroy the casing. Sad to know that a PC motherboard manufacturer like Asus did not implement their know-how and experience of bad capacitors on PC electronics with their routers.
redhawk0
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PostPosted: Sun Aug 23, 2009 14:02    Post subject: Reply with quote
thx-1138 wrote:
Yes, I have been on the same road with Dell Optiplex GX2xx series workstations.


Yep....GX270's....I had two of them.


So...you have verified that you have bad caps in your 500gP also?

I have two 520gU's...both are fine....but every unit should be checked just to be sure.

redhawk

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I currently test dd-wrt on Asus, Buffalo, Linksys, and Netgear. Too many to list.

Looking for more test units (newer models) for the project...got a brick?...PM me to make a donation. (USA) A donation is not a debricking service....it is a way to "Give back" to the dd-wrt project.

I do NOT provide personal assistance through chat or phone....so please don't ask.
thx-1138
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PostPosted: Sun Aug 23, 2009 14:06    Post subject: Reply with quote
I will this afternoon; definitely I have a bad PSU but I need to open up the router to get a close inspection of the capacitors. I will keep you posted.
redhawk0
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PostPosted: Sun Aug 23, 2009 14:20    Post subject: Reply with quote
OK...with a dremel tool and a cut-off wheel...I opened up the power brick.

Yes...it has a bad cap too. (black particulate is just plastic from when I opened it up.)

redhawk



IMG_0029.jpg
 Description:
Bad cap in the power brick of the Asus WL-500W unit - 5V@2.5A
 Filesize:  373.43 KB
 Viewed:  32706 Time(s)

IMG_0029.jpg



_________________
I currently test dd-wrt on Asus, Buffalo, Linksys, and Netgear. Too many to list.

Looking for more test units (newer models) for the project...got a brick?...PM me to make a donation. (USA) A donation is not a debricking service....it is a way to "Give back" to the dd-wrt project.

I do NOT provide personal assistance through chat or phone....so please don't ask.
Murrkf
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PostPosted: Sun Aug 23, 2009 14:48    Post subject: Reply with quote
It is GREAT that you finally have a WL500W to test builds on. That router has been such a P.I.T.A. with SP1 bricking it when a configuration was changed.
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thx-1138
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PostPosted: Sun Aug 23, 2009 23:53    Post subject: Reply with quote
Hello redhawk0,

Quote:
So...you have verified that you have bad caps in your 500gP also?

I have two 520gU's...both are fine....but every unit should be checked just to be sure.


I checked and my two 470mF and the single 1000 mF Teapo caps are well, flat as a coin. Problem points to the PSU so I will hold to open it until I get a replacement 5V 2.5A or 5V 3A PSU. Will post here with my results after I get the replacement PSU.

One favor to ask, could you provide the specs on the failed cap on the 5V 2.5A PSU pictured on your previous post? I could attempt to repair it and have it as a backup.
Mordak
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PostPosted: Mon Aug 24, 2009 0:18    Post subject: Reply with quote
Has anyone ever seen this issue on any of the Linksys routers?
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PostPosted: Mon Aug 24, 2009 7:32    Post subject: Reply with quote
Mordak wrote:
Has anyone ever seen this issue on any of the Linksys routers?


I checked all four of my WRT54G-TM routers and the caps were all nice and flat.
GeeTek
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PostPosted: Mon Aug 24, 2009 10:01    Post subject: Reply with quote
thx-1138 wrote:
Sad to know that a PC motherboard manufacturer like Asus did not implement their know-how and experience of bad capacitors on PC electronics with their routers.

Actually, they did. Don't you see the bad caps in the pictures above ? For the past 5 years I have flatly refuse to buy Asus' brand of anything after an overwhelming load of consistently shitty hardware AND bios firmware found in their motherboards. Hard to fathom how they seem to be such a popular brand.

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PetervdM
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PostPosted: Mon Aug 24, 2009 10:22    Post subject: Reply with quote
Mordak wrote:
Has anyone ever seen this issue on any of the Linksys routers?

yes, with a WAG54G

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redhawk0
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PostPosted: Mon Aug 24, 2009 21:14    Post subject: Reply with quote
thx-1138 wrote:
Hello redhawk0,

One favor to ask, could you provide the specs on the failed cap on the 5V 2.5A PSU pictured on your previous post? I could attempt to repair it and have it as a backup.


OK...I just got around to fixing this.

The original capacitor is a 10V 1200uF Polarized Electolytic Cap. This is a filtering cap on the output side (5V). The other cap (much larger) is 400V 33uF...this is a noise filtering cap on the input side. (120V side) Mine was good...no domed top.

I didn't have a 10V 1200uF but I had a 16V 1500uF...this is close enough. (just don't use any 6.3V caps...it won't be enough buffer long term)

I plugged it in and measured 5.286V unplugged....and plugged into the router it measures 5.134V at the connector....the router boots and operates fine.

redhawk

_________________
I currently test dd-wrt on Asus, Buffalo, Linksys, and Netgear. Too many to list.

Looking for more test units (newer models) for the project...got a brick?...PM me to make a donation. (USA) A donation is not a debricking service....it is a way to "Give back" to the dd-wrt project.

I do NOT provide personal assistance through chat or phone....so please don't ask.
barryware
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PostPosted: Mon Aug 24, 2009 21:21    Post subject: Reply with quote
This article is still around.. I found this years ago when trying to figure out why I had 3 rigs motherboards fail within a 1 month period.

My mobo's were all asus but the problem was bigger than asus.

http://www.techmati.com/articles/caps/index.htm

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