Bad caps in LCD monitor

[Davejr]

Hello. I'm trying to revive an LCD monitor with bulged caps in the power supply and I was wondering which specific ones to go with for this application. The ones that need replacing are 470mf 25v 105C. Three are definitely bulged and one is beginning to leak. Blinking power LED and no picture. Sceptre X220T-Naga.

[smason]

Re: Bad caps in LCD monitor

Hi, welcome to Badcaps!

You want to use a good-quality low ESR cap.
Several of us here use Panasonic FM, FC or FR series capacitors for monitors.
Digikey.com is a good source

[LLLlllou]

Re: Bad caps in LCD monitor

Hello. I'm trying to revive an LCD monitor with bulged caps in the power supply and I was wondering which specific ones to go with for this application. The ones that need replacing are 470mf 25v 105C. Three are definitely bulged and one is beginning to leak. Blinking power LED and no picture. Sceptre X220T-Naga.

We'll need a little more info to give you recomendations.

Manufacturor of caps, cap series (usually a 2 or 3 letter marking), and phisical dimentions in mm.

Also you should replace all caps from same manufacturor even if they aren't showing any signes of failure, if they're not bad now, they will be . . . soon.

[Davejr]

Re: Bad caps in LCD monitor

OK. The four that need replaced are CapXon 'KF C644 VENT', and they are 8mm x 16mm.

[Davejr]

Re: Bad caps in LCD monitor

Would these work?

http://www.digikey.com/product-detai...417-ND/2433551

[mariushm]

Re: Bad caps in LCD monitor

Yes, those will work.

If you can fit them (height wise), you may get the 35v rated version, for even better reliability.

[Davejr]

Re: Bad caps in LCD monitor

They are the exact same dimensions as the ones I'm pulling out.
What's a good solder to use?

[tom66]

Re: Bad caps in LCD monitor

Leaded or lead free is fine, if you use leaded remove all the original lead free before soldering the new ones on.

[Davejr]

Re: Bad caps in LCD monitor

I looked for a 35v with same dimensions, but didn't see one listed. Also, The 25v ones I did find say 'General Purpose'. Is that ok to use in the power supply? No ESR value is shown.
http://www.digikey.com/scripts/DKSea...58778153656121

It appears that they are out of stock on those and it says something about 'Lead Time'. I've never ordered though them before.

[mariushm]

Re: Bad caps in LCD monitor

They say "general purpose" to almost all electrolytic capacitors. It's a sort of "default" for electrolytic capacitors. They have "audio" capacitors that are still electrolytic capacitors so audio is a feature, or they consider being approved for "Automotive" use as a feature etc etc . Ignore that column.

Panasonic FM and FR are very low esr, long life capacitors, they're very good.

FR 470uf / 35v 10x17.5mm 8000h@105c : http://www.digikey.com/product-detai...441-ND/2433575
FR 470uF / 35v 8 x 22 mm 9000h@105c : http://www.digikey.com/product-detai...440-ND/2433574
FM 470uF / 35v 10x20mm 5000h@105c : http://www.digikey.com/product-detai...2415-ND/613776

FR 470/25 http://www.digikey.com/product-detai...418-ND/2433552
FR 470/25 http://www.digikey.com/product-detai...419-ND/2433553
FM 470/25 http://www.digikey.com/product-detai...2388-ND/613749

While it's not quite the same thing, you can treat the impedance column as an esr value. It's in mOhm so 30mOhm = 0.03 ohm

The old capacitors probably had 0.04-0.07 ohm esr and as they went bad, the value rose up gradually.

As long as you are very close to the value of old capacitors, or a bit below you're fine, and these series (FM and FR from Panasonic) are just right for monitors when it comes to current ripple and impedance but also when it comes to life - they're rated for 2.5-5 times more than your old capacitors.

[Davejr]

Re: Bad caps in LCD monitor

Thank you for all the help guys. I went ahead and ordered the ones from the link I posted previously. I was trying to keep all the dimensions identical because it gets pretty tight where they need to go. Might be a while before I get them though.

[LLLlllou]

Re: Bad caps in LCD monitor

Thank you for all the help guys. I went ahead and ordered the ones from the link I posted previously. I was trying to keep all the dimensions identical because it gets pretty tight where they need to go. Might be a while before I get them though.

Are you sure you measured correctly, Capxon KM series data sheet shows only a 10x16 for 470uf at 25v.

Either way, the 8x16 Panny FR you linked to on Digikey matches or exceeds all rataings of the 10x16 Capxon KM.

[Davejr]

Re: Bad caps in LCD monitor