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Capacitor size question

gyazbek

May 2, 2011
3
Joined
May 2, 2011
Messages
3
Hello All,

I recently replaced 5 capacitors in my plasma TV, and was curious about a few things.

The blown capacitors were marked 10v 3300 uF U1A and the temp was typical 105c (m). The replacement capacitors have the same specifications but are about 1/4 smaller and instead of U1A say 06A. Can this be a problem?

The TV turns on fine and displays image/sound; But when I turn it off a high pitch sound can be heard for at least 30 seconds.

Just want to make sure it isn't going to blow up =P


Thanks
Bill
 

davenn

Moderator
Sep 5, 2009
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Sep 5, 2009
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14,254
no thats ok, capacitor manufacturing has improved over recent years :)
as long as they have the same voltage, capacitance and temp rating you are ok

sounds like something else in one of the power supplies is still playing up

Dave
 

gyazbek

May 2, 2011
3
Joined
May 2, 2011
Messages
3
no thats ok, capacitor manufacturing has improved over recent years :)
as long as they have the same voltage, capacitance and temp rating you are ok

sounds like something else in one of the power supplies is still playing up

Dave

I feared I would have to open it up again... I didn't want to get to close to it while its doing the noise, so I kept the backcase on just in case the capacitor burst open. The sound is similar to capacitors charging;

-Bill
 

davenn

Moderator
Sep 5, 2009
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its likely to be one of the switchmode PSU oscillators being a bit noisy.
I usually find the noise eminating from the transformer in such supplies.

Dave
 

sacred cow

Apr 18, 2011
1
Joined
Apr 18, 2011
Messages
1
no thats ok, capacitor manufacturing has improved over recent years :)
as long as they have the same voltage, capacitance and temp rating you are ok

sounds like something else in one of the power supplies is still playing up

Dave

It ain't necessarily so. There is another important parameter and that is Equivalent Series Resistance. In general the lower the ESR is of a capacitor the better it is. Some critical applications need a very low ESR or oscillations, in particular, can occur. Normally the larger the physical size of the capacitor for a given voltage rating and capacitance, the lower the ESR but there are exceptions to this. I would be looking for lower ESR caps before doing anything else.

Glenn
 
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