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Leachim Sredna
Guest
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 Posted: Fri Jan 26, 2007 2:29 am Post subject: Help sought for an 8K7A+ with bad caps |
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Hi All,
I want to fix at minimum cost and trouble an 8K7A+ which seems to have
developed bad capacitors (some look quite bad and it's started random
reboots and lock-ups -- see thread *Spontaneous reboots* in alt.windows98).
I'm looking for somone who can supply a good replacement similar model board
or who can replace the caps for me (I'm in France).
I found another board on E-Bay but as it's in the US and described as
"refurbished" I'm a little leery of paying so much carriage for that one.
Help or ideas, anyone?
Thanks in advance,
Michael Anders |
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Davy
GURU
Joined: 30 Apr 2005
Posts: 1862
Location: Nr Manchester. UK
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| Posted: Fri Jan 26, 2007 2:38 pm Post subject: Re: Help sought for an 8K7A+ with bad caps |
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Could you not replace the caps.... should be easy enough do with a small 15 Watt soldering iron.
If you should take this route use LOW ESR (Effective Series Resistance), or low impedance 105 deg. C types, do not use standard capacitors...!
Obviously it's pointless if the capacitors have leaked and damaged the board, the gunge they spew 'could' eat away at the protective PCB lacquer then eat away the copper tracks.
Davy |
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Leachim Sredna
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| Posted: Sun Jan 28, 2007 3:32 pm Post subject: Re: Help sought for an 8K7A+ with bad caps |
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Actually, I've solved the spontaneous rebooting problem for the moment by
changing the PSU, notwithstanding the dodgy-looking caps, thanx !
"Davy" <no@spam.invalid> a écrit dans le message de news:
12rokhd19b1ot32@news.supernews.com...
| Quote: | Could you not replace the caps.... should be easy enough do with a
small 15 Watt soldering iron.
If you should take this route use LOW ESR (Effective Series
Resistance), or low impedance 105 deg. C types, do not use standard
capacitors...!
Obviously it's pointless if the capacitors have leaked and damaged the
board, the gunge they spew 'could' eat away at the protective PCB
lacquer then eat away the copper tracks.
Davy
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dave
Guest
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| Posted: Mon Jan 29, 2007 10:46 pm Post subject: Re: Help sought for an 8K7A+ with bad caps |
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Sometimes the caps can look bad and the board will still work. I have two
8RDA+ systems. One began not booting up or having a hard time booting. It
usually would boot after several attempts. I replaced the bad caps and that
did cure it. The other 8RDA+ also has bad looking caps but continues to
function properly to this day. Maybe the power supply in this machine is of
better quality and gives better voltages so the bad caps aren't as big a
problem. So for this reason I can see why the caps and the power supply are
related. So the question is, did you really fix the problem with a new
power supply? Maybe. Then again you may only have bandaided it.
Replacing caps easy enough to do? No, not so easy. I have 22 years
experience in electronics soldering and I struggled. It could have been
easier if I had specialized tools. It's not a job for a novice.
As to the job requiring special low esr, high temp caps? Not so. I used
standard electrolytics of 85c temp and have absolutely no problems.
DaveL
"Leachim Sredna" <leachim.sredna@wanadoo.fr> wrote in message
news:45bc6d35$0$5086$ba4acef3@news.orange.fr...
| Quote: | Actually, I've solved the spontaneous rebooting problem for the moment by
changing the PSU, notwithstanding the dodgy-looking caps, thanx !
"Davy" <no@spam.invalid> a écrit dans le message de news:
12rokhd19b1ot32@news.supernews.com...
Could you not replace the caps.... should be easy enough do with a
small 15 Watt soldering iron.
If you should take this route use LOW ESR (Effective Series
Resistance), or low impedance 105 deg. C types, do not use standard
capacitors...!
Obviously it's pointless if the capacitors have leaked and damaged the
board, the gunge they spew 'could' eat away at the protective PCB
lacquer then eat away the copper tracks.
Davy
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Davy
GURU
Joined: 30 Apr 2005
Posts: 1862
Location: Nr Manchester. UK
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| Posted: Sun Feb 25, 2007 5:48 pm Post subject: Re: Help sought for an 8K7A+ with bad caps |
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| Quote: | [quote="dave"]
As to the job requiring special low esr, high temp caps? Not so. I used
standard electrolytics of 85c temp and have absolutely no problems.
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Don't think I'll be doing the same in a warm environment and where high frequency ripple is concerned.
It's not a good idea to replace 105 deg. C caps with 85 deg.C types but it does make sense to replace 85 deg.C caps with 105 deg. C superior ones with better current ripple ratings as you should know being in the trade and that caps can look ok n' still can be bad. It's the ESR..... as the ESR rises so does the internal heating... and if the vent can't cope they pop or swell.
High ESR (effective series resistance) will also cause the capacitor not to decouple the supply lines allowing HF ripple on them from the clocking pulses and the switch-mode ripple frequency, hence the use of hi-temp low impedance devices....
....and caps can be easily replaced by anyone with some soldering ability and a little knowledge of mobo construction, the only tools required are a small soldering iron and a pair of mini side cutters, what specialized tools are they..?
| Quote: | [quote="dave"] Replacing caps easy enough to do? No, not so easy. I have 22 years
experience in electronics soldering and I struggled. It could have been
easier if I had specialized tools. It's not a job for a novice. |
If I had been in the trade 22 years and struggled to replace a capacitor.... I'd have given up or been fired a long long time ago.. and that includes surface mounted capacitors, which is not relevant here.. !
Davy |
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dave
Guest
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| Posted: Thu Mar 01, 2007 11:01 pm Post subject: Re: Help sought for an 8K7A+ with bad caps |
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"Davy" <no@spam.invalid> wrote in message
news:12u6sbqbb5madb9@news.supernews.com...
| Quote: | [quote="dave"]
As to the job requiring special low esr, high temp caps? Not so. I
used
standard electrolytics of 85c temp and have absolutely no problems.
Don't think I'll be doing the same in a warm environment and where
high frequency ripple is concerned.
It's not a good idea to replace 105 deg. C caps with 85 deg.C types
but it does make sense to replace 85 deg.C
caps with 105 deg. C superior ones with better current ripple ratings
as you should know being in the trade and that caps can look ok n'
still can be bad. It's the ESR..... as
the ESR rises so does the internal heating... and if the vent can't
cope they pop or swell.
High ESR (effective series resistance) will also cause the capacitor
not to decouple the supply lines allowing HF ripple on them from the
clocking pulses and the switch-mode ripple frequency, hence the use of
hi-temp low impedance devices....
...and caps can be easily replaced by anyone with some soldering
ability and a little knowledge of mobo construction, the only tools
required are a small soldering iron and a pair of mini side cutters,
what specialized tools are they..?
[quote="dave"] Replacing caps easy enough to do? No, not
so easy. I have 22 years
experience in electronics soldering and I struggled. It could have
been
easier if I had specialized tools. It's not a job for a novice.
[b:864825d93d][i:864825d93d]If I had been in the trade 22 years and
struggled to replace a capacitor.... I'd have given up or been fired a
long long time ago.. and that includes surface mounted capacitors,
which is not relevant here.. ![/i:864825d93d][/b:864825d93d]
Davy
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How many motherboards have you done with only a soldering iron and side
cutters? I don't think you know what you are talking about. You normally
would need something to remove the old solder. I have done this job with
basic capacitors and can report no lockups. On top of that, the system is
overclocked. My experience is cold hard fact. Nothing you can say can
dispute it.
DaveL |
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Davy
GURU
Joined: 30 Apr 2005
Posts: 1862
Location: Nr Manchester. UK
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| Posted: Sat Mar 03, 2007 5:42 pm Post subject: Re: Help sought for an 8K7A+ with bad caps |
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I think it is you who dosen't know what you are talking about and you must be the only person what does such things...!
Why do all mobo manufacturers not use standard 85 deg. C caps, they will sure save some cash, also why is it that you see 105 deg C low ESR caps in mobos... to make them look pretty? Please explain.
It is clear if you are replacing these with standard types you are doing a sub-standard repair.... wonder what the manufacturer would think let alone your customers? It could be you are doing this so that the mobo keeps coming back for repair.... instead of doing a quality job.
It is plainly obvious that a 85deg C component ain't gonna last as long as a 105 deg C type in a warm environment... you also can't see the reason for using low ESR types.... I doubt you even take their current ripple rating into consideration...
.... you have been in the trade 22 years and can not see this point.
Your gonna tell me you even use them in power supplies as well.. ?
Oh... and to remove solder from a plated through hole in a multilayer board is easy.... and no it's not trying to force the component leads through the holes which can do damage, you gotta clean the hole first and it ain't with a hot air tool, and desoldering braid is useless.
Davy |
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Zephyr
Guest
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| Posted: Mon Mar 19, 2007 5:01 am Post subject: Re: Help sought for an 8K7A+ with bad caps |
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I'm sorry, but all the hype is interesting read. I replaced all the caps on
"my" computer [8K7A with 85 degree C caps [which by the way if your board is
running over 185 degrees F., you got other problems] and have had no ill
effects. I replaced them several years ago, and the board's been fine... no
hiccups or BSOD.
--
Zyp
"dave" <nospam> wrote in message
news:_vidnXM9nPPtm3rYnZ2dnUVZ_qKqnZ2d@comcast.com...
| Quote: |
"Davy" <no@spam.invalid> wrote in message
news:12u6sbqbb5madb9@news.supernews.com...
[quote="dave"]
As to the job requiring special low esr, high temp caps? Not so. I
used
standard electrolytics of 85c temp and have absolutely no problems.
Don't think I'll be doing the same in a warm environment and where
high frequency ripple is concerned.
It's not a good idea to replace 105 deg. C caps with 85 deg.C types
but it does make sense to replace 85 deg.C
caps with 105 deg. C superior ones with better current ripple ratings
as you should know being in the trade and that caps can look ok n'
still can be bad. It's the ESR..... as
the ESR rises so does the internal heating... and if the vent can't
cope they pop or swell.
High ESR (effective series resistance) will also cause the capacitor
not to decouple the supply lines allowing HF ripple on them from the
clocking pulses and the switch-mode ripple frequency, hence the use of
hi-temp low impedance devices....
...and caps can be easily replaced by anyone with some soldering
ability and a little knowledge of mobo construction, the only tools
required are a small soldering iron and a pair of mini side cutters,
what specialized tools are they..?
[quote="dave"] Replacing caps easy enough to do? No, not
so easy. I have 22 years
experience in electronics soldering and I struggled. It could have
been
easier if I had specialized tools. It's not a job for a novice.
[b:864825d93d][i:864825d93d]If I had been in the trade 22 years and
struggled to replace a capacitor.... I'd have given up or been fired a
long long time ago.. and that includes surface mounted capacitors,
which is not relevant here.. ![/i:864825d93d][/b:864825d93d]
Davy
How many motherboards have you done with only a soldering iron and side
cutters? I don't think you know what you are talking about. You normally
would need something to remove the old solder. I have done this job with
basic capacitors and can report no lockups. On top of that, the system
is
overclocked. My experience is cold hard fact. Nothing you can say can
dispute it.
DaveL
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Davy
GURU
Joined: 30 Apr 2005
Posts: 1862
Location: Nr Manchester. UK
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| Posted: Thu Mar 22, 2007 12:10 am Post subject: Re: Help sought for an 8K7A+ with bad caps |
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It's not just the ambient, ever thought what effect the ripple current has on a capacitor - especially if it's not low ESR.. ever wondered what made them go in the first place?
They go even in a very cool environment not just computers and it ain't the age.
So, it's ok then to swap a 105 deg. C hf type cap for a plain ol' standard 85 deg C. - sorry, I don't think so.
Maybe you'll explain why they use them in the first place?
Davy |
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dave
Guest
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| Posted: Sat Mar 31, 2007 12:01 am Post subject: Re: Help sought for an 8K7A+ with bad caps |
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Davy,
Here is the REAL reason they went bad:
"The cause...
This inferior and flawed electrolyte formula was used by a number of
component manufacturers that sold to many different, reputable, and well
known motherboard manufacturers. This problem isn't isolated to one
particular brand of motherboard, and not even isolated to motherboards
alone. I won't mention brands, but a VERY popular monitor manufacturer has
been plagued with RMA's on some of their monitors that were built using
these inferior capacitors. This problem has been reported in computer
motherboards, monitors, televisions, radios, and stereo equipment. Through
my experiences owning a service center, I've personally seen and serviced a
large number of 'high-end' equipment that had prematurely failed
capacitors."
http://www.badcaps.net/causes/
Read the above web page. It explains the "large-scale industrial espionage
foul-up".
DaveL
"Davy" <no@spam.invalid> wrote in message
news:130ff7spm0rkj04@news.supernews.com...
| Quote: | It's not just the ambient, ever thought what effect the ripple current
has on a capacitor - especially if it's not low ESR.. ever wondered
what made them go in the first place?
They go even in a very cool environment not just computers and it
ain't the age.
So, it's ok then to swap a 105 deg. C hf type cap for a plain ol'
standard 85 deg C. - sorry, I don't think so.
Maybe you'll explain why they use them in the first place?
Davy
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Zephyr
Guest
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| Posted: Mon Apr 02, 2007 12:40 am Post subject: Re: Help sought for an 8K7A+ with bad caps |
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I even saw larger 440v 50uf caps that explode. [New under warranty.] The
environment they are subject too makes computer motherboards look like kids
milk. Apparently, the electrolyte problem got into everything over the last
several years.
BTW: I replaced the blotted caps on my 8k7a a few years back and haven't
had any trouble... been rock solid [both RAID 8k7a+ and the 8k7a boards on
two computers.]
--
Zyp
"dave" <nospam> wrote in message
news:PsednXnoV41uB5DbnZ2dnUVZ_oCmnZ2d@comcast.com...
| Quote: | Davy,
Here is the REAL reason they went bad:
"The cause...
This inferior and flawed electrolyte formula was used by a number of
component manufacturers that sold to many different, reputable, and well
known motherboard manufacturers. This problem isn't isolated to one
particular brand of motherboard, and not even isolated to motherboards
alone. I won't mention brands, but a VERY popular monitor manufacturer
has
been plagued with RMA's on some of their monitors that were built using
these inferior capacitors. This problem has been reported in computer
motherboards, monitors, televisions, radios, and stereo equipment.
Through
my experiences owning a service center, I've personally seen and serviced
a
large number of 'high-end' equipment that had prematurely failed
capacitors."
http://www.badcaps.net/causes/
Read the above web page. It explains the "large-scale industrial
espionage
foul-up".
DaveL
"Davy" <no@spam.invalid> wrote in message
news:130ff7spm0rkj04@news.supernews.com...
It's not just the ambient, ever thought what effect the ripple current
has on a capacitor - especially if it's not low ESR.. ever wondered
what made them go in the first place?
They go even in a very cool environment not just computers and it
ain't the age.
So, it's ok then to swap a 105 deg. C hf type cap for a plain ol'
standard 85 deg C. - sorry, I don't think so.
Maybe you'll explain why they use them in the first place?
Davy
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