Can I replace damaged capacitors in my power supply with a 1000uf cap?

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Discussion Overview

The discussion revolves around the replacement of damaged capacitors in a power supply for a monitor or TV. Participants explore the feasibility of substituting a 1000μF capacitor for an 820μF capacitor and share experiences related to repairs, sourcing components, and troubleshooting symptoms of the device.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant describes a monitor that powers on briefly before shutting off, suspecting the power supply due to visibly damaged capacitors.
  • Another participant questions whether a 1000μF capacitor can substitute for an 820μF capacitor, suggesting it may be acceptable if it is a filter capacitor.
  • Some participants express uncertainty about whether the capacitor in question is indeed a filter capacitor, with one noting that 820μF is an unusual value for such applications.
  • A participant shares their experience of successfully sourcing a capacitor locally and expresses a desire to learn more about electronics.
  • Concerns are raised about the potential for bad smells or noises if capacitors are indeed failing, and suggestions are made to check computer settings as a possible cause of the monitor's issues.
  • One participant mentions the importance of ensuring the polarity of the capacitors is correct before powering the device back on.
  • Another participant warns about the risks of handling capacitors that can hold charge even after being powered off.
  • There is a discussion about the condition of the original capacitors, with one participant noting they appeared "blotted" or enlarged, indicating potential failure.
  • Ultimately, a participant reports success after replacing the capacitors, indicating the monitor is functioning well again.

Areas of Agreement / Disagreement

Participants express varying degrees of confidence regarding the substitution of capacitors and the identification of the problem. While some agree on the potential for a 1000μF capacitor to work, others question the appropriateness of the value. The discussion includes both troubleshooting advice and personal experiences, but no consensus is reached on the best approach to the repair.

Contextual Notes

Participants mention the importance of ensuring correct polarity and caution against the dangers of charged capacitors. There is also a suggestion that multiple capacitors may be in poor condition, but this remains unverified.

Who May Find This Useful

This discussion may be useful for individuals interested in electronics repair, particularly those dealing with power supply issues in monitors or TVs, as well as those seeking advice on sourcing components locally.

slee95
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The monitor/ tv will power on for around 30s and i can see all the icons on the tv but then will shut off I'm thinking its the power supply so i took a look at it and 3 of the capacitors look bad i have no clue where to get capacitors in the Harrisburg Mechanicsburg are. I don't want to buy online i want to buy from a store though. Can i use a 1000uf cap the 3 caps that look bad are 820uf 25v.
 
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If you don't want to buy online and you can't find one in your area, you got a problem!
 
but would a 1000uf substitute for a 820uf cap?
 
slee95 said:
but would a 1000uf substitute for a 820uf cap?

If it is a filter cap, yes.
 
820μF is a funny value to put in a psu filter rather than 1000 are you sure it is a filter cap as yungman said?
 
there's lots of sites where people discuss their repairs

my son fixed a 50 inch samsung with help from folks here
three Radio Shack caps got his trashpile-rescued tv going for around seven bucks



http://forums.anandtech.com/forumdisplay.php?f=38

try a google search on your model and symptom.
 
I got the capacitor. Noticed a tv store on my way to a doctors appoint and got it for $6. filter cap? I'm still learning about electronics at votech the cap is a dc capacitor like this pic http://www.google.com/imgres?num=10...w=131&start=0&ndsp=18&ved=1t:429,r:1,s:0,i:75. Ok now to install it will i have to be grounded while handling the power supply? If so i do not own a grounding reistband what else could i use to ground my self?
 
If you had bad capacitors, you would be getting bad smells and possibly crackling noises.


If you are using Windows XP, there is a "power options" icon in Control Panel which could turn the monitor off in as little as 1 minute.
Worth checking this by borrowing a friend's monitor to check it. If your friend's monitor turns off too, then it could be a computer setting.

If you power up the monitor and computer separately, then turn the computer off then on but leave the monitor turned on, do you get the same effect?
The monitor should stay off if it is causing the problem, but it should give a short period of normal picture if it is the computer doing it.
 
vk6kro said:
If you had bad capacitors, you would be getting bad smells and possibly crackling noises.


If you are using Windows XP, there is a "power options" icon in Control Panel which could turn the monitor off in as little as 1 minute.
Worth checking this by borrowing a friend's monitor to check it. If your friend's monitor turns off too, then it could be a computer setting.

If you power up the monitor and computer separately, then turn the computer off then on but leave the monitor turned on, do you get the same effect?
The monitor should stay off if it is causing the problem, but it should give a short period of normal picture if it is the computer doing it.
It does show all the computer icons for a very brief time then shuts off and 3 of the caps look really blotted on the power supply so i will replace them but did not know if its static sensitive. The monitor/tv it has the port for either or is a samsung with speakers on the side and is at work so i don't know the model numb. but i will know tomorrow.
 
  • #10
Oh the computer tower i tested it on was a e-machines with xp. I like the monitor and they were going to throw it away so I'm attempting to repair it. When i pull the power cord off and back on it will show the computer icons but only briefly the monitor works but only stay on for 30s or so.
 
  • #12
That sounds better, but don't waste too much money on it.

Nobody wants CRT monitors any more and you can pick them up cheaply ($15) or free.

No, power supplies are not usually static sensitive, but beware of capacitors that can hold charges long after the power is turned off. They can zap unwary fingers.
 
  • #13
thanks vk6kro the caps only costed be $6 while i have the back off of it what other things should i look at before powering it up again?
 
  • #14
You realize that this is a bit of a gamble, so if you are sure you have the polarity of the capacitors right and you haven't accidentally pulled any plugs out of their sockets, just turn it on and see what happens.

If it behaves the same as it did before, I would ditch it.

Collect your capacitors out of it and any power transistors, Schottky diodes, ICs, ferrite toroids or heatsinks for your junk box and get rid of what is left.
 
  • #15
Than kvk6kro very much :).
 
  • #16
slee95 said:
It does show all the computer icons for a very brief time then shuts off and 3 of the caps look really blotted on the power supply so i will replace them
I'm intrigued; what does a capacitor look like to appear "blotted"? http://img845.imageshack.us/img845/1143/confusedsmiley010.gif

My feeling is that if 3 capacitors can be seen to have burst, there are probably 10 times as many hidden away on other boards, or on the underside, that are in an equally poor state.
 
Last edited by a moderator:
  • #17
The monitor lives again and is working good :) NascentOxygen yes the old ones were partially exploded and no the caps where only on one side. :)
 
  • #18
slee95 said:
The monitor lives again and is working good :)
I hope your rescue enjoys a long and productive second life. :smile:
 
  • #19
Thank you NascentOxygen very much :).
 

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