Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Old May 16th 13, 02:25 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 6,772
Default Very poor electros ...

Had a Rega Elex hifi amp fetch up on the bench today. It was low on one
channel compared to the other. On a 'scope, both channels looked a bit
scruffy at the output, as well. Both channels were the same level and
reasonably clean at the volume control. It's a fully discrete power amp
south of the volume control, and nothing was obviously wrong in the bad
channel. So just for sport, I picked up the ESR meter with a view to giving
all the caps a quick read. The first one that I put the meter across, was
quite close to the driver transistors, and it went over 60 ohms. Ah-ha
thought I. Got it ! I checked the cap on the opposite side of the circuit
near to the complementary driver, and it too had a high ESR. Putting this
down to them being near to components that probably ran pretty warm, I
didn't think a lot more about it, and just went ahead and replaced them.
That restored the level of the 'bad' channel - to TWICE the level of the
'good' channel. At that point, the alarm bells started to ring. There are
only three values of cap used - 2.2 uF, 10 uF and 22 uF. Curiously, they are
all marked with the same "C" numbers on the board, i.e. all of the 10 u's
are called "C8", the 22u's are "C10" and the 2.2u's are "C9".

Anyway, I started to measure them all, and every single one, in both
channels, is either high ESR or completely open. Over 20 caps in all. I've
pulled them all out, and re-measured them out of circuit, and the state of
them is confirmed. I hadn't got enough in stock, so I've got some more
coming tomorrow. Most of them are not located near to hot-running
components, so I'm at a bit of a loss to explain how that many caps all go
bad. It will be interesting to see how much better the amp performs when all
of the caps are replaced, and whether the scruffiness of the output waveform
will be improved.

Arfa


  #2   Report Post  
Old May 16th 13, 04:06 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2007
Posts: 3,892
Default Very poor electros ...

On Thu, 16 May 2013 02:25:09 +0100, "Arfa Daily"
wrote:

Anyway, I started to measure them all, and every single one, in both
channels, is either high ESR or completely open. Over 20 caps in all.


Most likely they are all counterfeit parts. You can sometimes
recognize them by various differences from the real parts, but what
I'm seeing is that the counterfeits are getting closer to the real
thing.
http://www.badcaps.net/wiki/index.php?title=Counterfeit_Capacitor
https://www.google.com/search?q=capacitor+fake&tbm=isch
https://www.google.com/search?q=capacitor+counterfeit&tbm=isch

My collection:
http://802.11junk.com/jeffl/pics/repair/bad-caps.jpg


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #3   Report Post  
Old May 16th 13, 04:53 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jun 2009
Posts: 1,718
Default Very poor electros ...


"Jeff Liebermann = FOOL "
"Arfa Daily"
wrote:

Anyway, I started to measure them all, and every single one, in both
channels, is either high ESR or completely open. Over 20 caps in all.


Most likely they are all counterfeit parts.



** Utter horse manure.




.... Phil







  #4   Report Post  
Old May 16th 13, 06:58 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Sep 2006
Posts: 379
Default Very poor electros ...

In article ,
Arfa Daily wrote:

Most of them are not located near to hot-running
components, so I'm at a bit of a loss to explain how that many caps all go
bad.


Could they date to the "stolen partial electrolyte formula" era? My
recollection is that caps made with the defective electrolyte tend to
start going gnaester-upwards after a few thousand hours with power
applied... I don't recall heat being a requirement for the failure to
occur.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
  #5   Report Post  
Old May 16th 13, 07:09 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jun 2009
Posts: 1,718
Default Very poor electros ...


"Dave Platt"
Arfa Daily

Most of them are not located near to hot-running
components, so I'm at a bit of a loss to explain how that many caps all go
bad.


Could they date to the "stolen partial electrolyte formula" era?


** Q. Why was that formula stolen ??

A. Because it was the secret to making tiny, high value and LOW ESR
electros for use in PC mobos and SMPS.

Not for low value, regular electros in audio.




...... Phil






  #6   Report Post  
Old May 16th 13, 07:50 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 1,833
Default Very poor electros ...

Jeff Liebermann wrote:
On Thu, 16 May 2013 02:25:09 +0100, "Arfa Daily"
wrote:

Anyway, I started to measure them all, and every single one, in both
channels, is either high ESR or completely open. Over 20 caps in all.


Most likely they are all counterfeit parts. You can sometimes
recognize them by various differences from the real parts, but what
I'm seeing is that the counterfeits are getting closer to the real
thing.
http://www.badcaps.net/wiki/index.php?title=Counterfeit_Capacitor
https://www.google.com/search?q=capacitor+fake&tbm=isch
https://www.google.com/search?q=capacitor+counterfeit&tbm=isch

My collection:
http://802.11junk.com/jeffl/pics/repair/bad-caps.jpg


Ha, I like the green "Rifeking" branded ones.


  #7   Report Post  
Old May 16th 13, 08:27 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Apr 2008
Posts: 5,178
Default Very poor electros ...

Arfa Daily wrote in message
...
Had a Rega Elex hifi amp fetch up on the bench today. It was low on one
channel compared to the other. On a 'scope, both channels looked a bit
scruffy at the output, as well. Both channels were the same level and
reasonably clean at the volume control. It's a fully discrete power amp
south of the volume control, and nothing was obviously wrong in the bad
channel. So just for sport, I picked up the ESR meter with a view to

giving
all the caps a quick read. The first one that I put the meter across, was
quite close to the driver transistors, and it went over 60 ohms. Ah-ha
thought I. Got it ! I checked the cap on the opposite side of the circuit
near to the complementary driver, and it too had a high ESR. Putting this
down to them being near to components that probably ran pretty warm, I
didn't think a lot more about it, and just went ahead and replaced them.
That restored the level of the 'bad' channel - to TWICE the level of the
'good' channel. At that point, the alarm bells started to ring. There are
only three values of cap used - 2.2 uF, 10 uF and 22 uF. Curiously, they

are
all marked with the same "C" numbers on the board, i.e. all of the 10 u's
are called "C8", the 22u's are "C10" and the 2.2u's are "C9".

Anyway, I started to measure them all, and every single one, in both
channels, is either high ESR or completely open. Over 20 caps in all. I've
pulled them all out, and re-measured them out of circuit, and the state of
them is confirmed. I hadn't got enough in stock, so I've got some more
coming tomorrow. Most of them are not located near to hot-running
components, so I'm at a bit of a loss to explain how that many caps all go
bad. It will be interesting to see how much better the amp performs when

all
of the caps are replaced, and whether the scruffiness of the output

waveform
will be improved.

Arfa


What date? All same make ?


  #8   Report Post  
Old May 16th 13, 05:11 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2007
Posts: 3,892
Default Very poor electros ...

On Thu, 16 May 2013 13:53:49 +1000, "Phil Allison"
wrote:


"Jeff Liebermann = FOOL "
"Arfa Daily"
wrote:

Anyway, I started to measure them all, and every single one, in both
channels, is either high ESR or completely open. Over 20 caps in all.


Most likely they are all counterfeit parts.



** Utter horse manure.
... Phil


Fake Panasonic caps:
http://www.youtube.com/watch?v=yKPyf7O8Uyg
http://www.panasonic.com/industrial/electronic-components/tertiary-navigation/product-information/alerts.aspx
http://www.badcaps.net/forum/showthread.php?t=13259
http://www.badcaps.net/forum/showthread.php?t=14047
(Registration required to view photos).

Fake Rubycon:
http://www.youtube.com/watch?v=g9E-CXVFQ0M

Nichicon:
http://www.shenzhen-standard.com/2010/09/13/beware-of-counterfeit-capacitor-products/

The Japanese manufacturers parts are being cloned by some Chinese
manufacturers. I've seen my share of both flavors of fake parts,
mostly bought on eBay but also extracted from repairs.

General interest:
http://www.hardwaresecrets.com/printpage/How-to-Identify-Japanese-Electrolytic-Capacitors/595
http://www.capacitorindustry.com/the-facts-about-counterfeiting-cant-be-ignored
http://www.ebnonline.com/author.asp?section_id=2467&doc_id=250412
http://www.ebnonline.com/author.asp?section_id=1084&doc_id=247776

Incidentally, it's not just capacitors.
Lubricants:
http://www.shenzhen-standard.com/2011/03/31/police-seized-boxes-of-counterfeit-lubricants/
Lamps:
http://www.best-news.us/news-4407218-Taiyuan-seized-a-large-number-of-counterfeit-international-brand-lamps-involved-more-than-500-million.html
Misc:
http://counterfeitparts.wordpress.com
http://www.cbp.gov/xp/cgov/newsroom/news_releases/national/01092012.xml

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #9   Report Post  
Old May 16th 13, 11:09 PM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jun 2009
Posts: 1,718
Default Very poor electros ...


"Jeff Liebermann = IDIOT "
"Phil Allison"

"Jeff Liebermann = FOOL "
"Arfa Daily"

Anyway, I started to measure them all, and every single one, in both
channels, is either high ESR or completely open. Over 20 caps in all.

Most likely they are all counterfeit parts.



** Utter horse manure.


... Phil


Fake Panasonic caps:



** FFS you TENTH WITTED JERK OFF !!!

Fake caps exist, but AD's are NOT likely to be examples.

The values are too low, for a start.



.... Phil





  #10   Report Post  
Old May 17th 13, 02:39 AM posted to sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 6,772
Default Very poor electros ...



"Phil Allison" wrote in message
...

"Jeff Liebermann = IDIOT "
"Phil Allison"

"Jeff Liebermann = FOOL "
"Arfa Daily"

Anyway, I started to measure them all, and every single one, in both
channels, is either high ESR or completely open. Over 20 caps in all.

Most likely they are all counterfeit parts.


** Utter horse manure.


... Phil


Fake Panasonic caps:



** FFS you TENTH WITTED JERK OFF !!!

Fake caps exist, but AD's are NOT likely to be examples.

The values are too low, for a start.



... Phil



Yes, I don't think it is because they are fakes. They are made by a company
called Eurocap. I have never heard of them before. The amp is actually quite
old, so I guess you could argue that they had reached the end of their
specced life. However, looking again at it today, it's one of those designs
where the entire case is a diecast heatsink, and there are no ventilation
slots at all. I suppose that the interior probably heats up quite a bit when
the amp is doing some work, and it is this that has led to the demise of all
the caps.

I did the replacement today, and ran the ESR meter over them all again out
of circuit. The 2.2 u's were fairly consistent at around 16 ohms. The new
replacements were about 1.5 ohms. Not one of the 10u's and 22u's was less
than 60 ohms, and several were completely open.

Once they had all been replaced, both channels had identical output, and the
sine wave I put in it now came out totally clean.

Arfa



Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Are you poor? Steve B[_10_] Metalworking 48 September 27th 11 04:24 AM
Easy ESR meter for Electros Phil Allison[_2_] Electronics Repair 3 January 26th 11 05:13 AM
Why a no-no to use 40/50KHz high V electros for 50/60 Hz use? n cook Electronics Repair 8 May 7th 07 10:31 AM
Help me die poor! Hank UK diy 11 March 5th 07 07:03 AM
Replacing those 'can' type electros tempus fugit Electronics Repair 3 April 12th 05 01:56 AM


All times are GMT +1. The time now is 07:03 PM.

Powered by vBulletin® Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright 2004-2019 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"

 

Copyright © 2017