Samwha UT 450v 4.7uF 125ma@120Hz replacement

[Stormosrter]

I'm ordering parts for my old 42in Phillips so I can give it to granny but I can't find anything with specs that match or surpass the one SamWha UT 450v 4.7uF 125ma@120Hz ripple. It looks like it might be a little bloated and since I don't have an ESR meter to test it I want to buy replacements for all caps on the board. I plan to place my order tonight or in the mourning whether I find and alternative to this cap or not. So far I have found everything else on Digi-Key.

Super simple version.
Need to find alternative to Samwha UT Series 450v 4.7uF with ripple rating of 125ma@120Hz

Spec sheet http://www.datasheets360.com/pdf/-2813557024132716258

This is on the power side of a Phillips 42pfl5603d/27 power board.

Almost forgot it can't be more than 10mm dia and 30mm tall.

[stj]

Re: Samwha UT 450v 4.7uF 125ma@120Hz replacement

rubycon BXC beats the crap out of that.

[Stormosrter]

Re: Samwha UT 450v 4.7uF 125ma@120Hz replacement

Unless I misunderstood what I read on these forums in several threads about the ripple needing to be equal or greater than the original on these TV power boards, how is the BXC's 44ma@120hz equal to or greater than 125ma@120hz of the original generic cap? If greater ripple means a lower ma then I'm going to have to repic my entire order again.

[stj]

Re: Samwha UT 450v 4.7uF 125ma@120Hz replacement

??
220ma ripple for 10x20mm, 180ma for 10x16mm

[Stormosrter]

Re: Samwha UT 450v 4.7uF 125ma@120Hz replacement

That's at 100khz not 120hz so unless I misunderstood the box that states "MULTIPLIER FOR RIPPLE CURRENT" on page one of the spec sheet you multiply 220 x 0.2 to get 44ma@120hz. Digi-key even lists it as 44ma ripple but doesn't state what frequency.

https://www.digikey.com/product-deta...X20-ND/3566098

[stj]

Re: Samwha UT 450v 4.7uF 125ma@120Hz replacement

i'm pretty sure that's wrong, it's more likely 220/1.20 (183ma)
you dont de-rate to nothing over a 20hz difference.

what's the circuit anyway, what frequency will the cap see?

[Stormosrter]

Re: Samwha UT 450v 4.7uF 125ma@120Hz replacement

From BXC sheet

◆MULTIPLIER FOR RIPPLE CURRENT
Frequency（Hz）    120   1k   10k  100k≦
Coefficient 1～5.6μF  0.20  0.40  0.80  1.00

From SamWha sheet

 FREQUENCY COEFFICIENT OF PERMISSIBLE RIPPLE CURRENT
Frequency   50Hz   120Hz  1kHz   50kHz  100kHz≦
Coefficient  0.80   1.00   1.10   1.30   1.40

I don't think its a 20hz difference unless I'm completely misunderstanding these charts. The samwha was rated at 120hz and the ruby at 100khz (100,000hz unless I'm mistaken).

As for the circuit, I have no idea. I'm just trying to replace the caps on a LCD TV's power board using common sense, my ability to solder, the tiny bit of very very basic electrical knowledge I already have and what I have read on these forums today.

[stj]

Re: Samwha UT 450v 4.7uF 125ma@120Hz replacement

can you attach the datasheet pls.
what is it going in btw.

[budm]

Re: Samwha UT 450v 4.7uF 125ma@120Hz replacement

https://cdn.badcaps-static.com/pdfs/...f6d3e3e891.pdf
https://cdn.badcaps-static.com/pdfs/...34293019f9.pdf

You do need to use that multiplier to compare the rating at the same frequency.
But if you look at the spec sheet of the SAMWHA for the 450V rating caps, it does not show what the frequency is being used. the 400VDC does show the ripple rating at 120HZ.
I think that rating of 125mA is done at 100KHz, I cannot see it can have that much rating at 120Hz.

[Stormosrter]

Re: Samwha UT 450v 4.7uF 125ma@120Hz replacement

Thank you for the information budm. I guess I'll just order the highest rated ripple in stock just in case and not replace that cap unless it starts bulging or I buy and test it with an ESR meter.

https://www.digikey.com/product-deta...5343-ND/245097

Also just to confirm, am I correct in assuming that when converting ripple you just multiply the rating in the chart by the number under the hz rating on the other chart?

Example of how I have been doing it using the 450v 4.7uf 220ma@100k on BXC datasheet and converting to 120hz. It shows 0.20 under 120hz so I just multiply 220ma by 0.2.

220x0.20=44ma@120hz

Is this correct?

[budm]

Re: Samwha UT 450v 4.7uF 125ma@120Hz replacement

44mA is correct. If you look at most manufacturer for the same 4.7uF 450VDC you will see that it has about the same ripple current rating around that range.