Recapping monitors and PSU

[dealova]

Do we need to use Low ESR & High ripple caps for LCD/LED monitors & computer's power supply ? Or only for motherboards. Thanks.

[ben7]

Re: Recapping monitors and PSU

Preferrably, yes.

BUT, don't put capacitors with very very low ESR in the power supplies. The low ESR may make the power supply unstable, causing an audible whine or buzzing. This also creates more voltage fluctuations on the output. You see, PSUs are designed to use certain capacitors, not just any plain ol' ones!

[mariushm]

Re: Recapping monitors and PSU

The dc-dc converters on motherboards and video cards usually run at 500kHz or more, sometimes they even switch at more than 1 Mhz.

Switching power supplies run at high frequencies but not quite as high as those found on motherboards... usually, they work at around 50-80 kHz and higher.

Monitors use switching power supplies to get the voltages they need, computer power supplies are switching power supplies and so on.

Just like with motherboards, low esr and high ripple capacitors are very recommended but you have to pay attention because the circuit can be designed to work with capacitors that have an esr value that's a bit higher compared to the esr of capacitors you would find on motherboards.
These capacitors would still be considered "low esr" but have worse ESR compared to those series of capacitors usually found on motherboards.

So you do have to check the datasheets and not just use the best possible capacitor which you would stock for servicing motherboards or video cards. Doing so may make the power supply unstable or noisy or die sooner than expected.

[ben7]

Re: Recapping monitors and PSU

The dc-dc converters on motherboards and video cards usually run at 500kHz or more, sometimes they even switch at more than 1 Mhz.

Switching power supplies run at high frequencies but not quite as high as those found on motherboards... usually, they work at around 50-80 kHz and higher.

Monitors use switching power supplies to get the voltages they need, computer power supplies are switching power supplies and so on.

Just like with motherboards, low esr and high ripple capacitors are very recommended but you have to pay attention because the circuit can be designed to work with capacitors that have an esr value that's a bit higher compared to the esr of capacitors you would find on motherboards.
These capacitors would still be considered "low esr" but have worse ESR compared to those series of capacitors usually found on motherboards.

So you do have to check the datasheets and not just use the best possible capacitor which you would stock for servicing motherboards or video cards. Doing so may make the power supply unstable or noisy or die sooner than expected.

LOL you pretty much said exactly what I said...

[dealova]

Re: Recapping monitors and PSU

Thanks guys. Is there any clue what's the minimum impedance I should take ? above 0.10 ohm perhaps ?

[c_hegge]

Re: Recapping monitors and PSU

Try to match the original caps (or get close). If they are GP caps, then go with 'entry level' Low ESR caps (Panasonic FC, Nichicon PW, or Chemi-con LXZ)