Need advice in finding low impedance repalcement capacitor

[fun148]

I am trying to fix a no picture problem with my Samsung HL61A750 DLP TV, and I am having difficulty in finding the right capacitor to replace the one below. It is bulging on the top, so I am pretty sure that it is bad. It is used in the sub power supply BP96-01726B PCB:

SAMHWA WL – extremely low impedance series

100uf 450V Impedance = 0.71 Ohm Ripple Current = 1200 mA @105C

Cap Dimension 18x35.5
Lead spacing 7.5 mm
Copper dia. 0.8 mm

Datasheet link:

Please help. Thanks.

[Jooo]

Re: Need advice in finding low impedance repalcement capacitor

If you want a high reliability replacement I would go for NCC KXG series. The ESR doesn't really matter there.
If could take picture of the capacitor in question, we could check it and give you another opinion about the state of the cap. It may not be bad.
Of course, the only certain way of knowing if it is good or not, is using ESR meter.

[fun148]

Re: Need advice in finding low impedance repalcement capacitor

Thanks so much, Jooo. I am sorry that I do not have a decent digital camera to take a photo of my cap, but it has a very obvious bulge on top. In any case, I want to replace it along with the other caps to be on the safe side.

One last question if you do not mind, what do you think about Nichicon CY series as compared to NCC KXG series that you have suggested?

Thanks for your input.

[Agent24]

Re: Need advice in finding low impedance repalcement capacitor

CY looks nice but the datasheet says 100uF 450v is only 835mA RCR. Might be a problem.

[fun148]

Re: Need advice in finding low impedance repalcement capacitor

CY looks nice but the datasheet says 100uF 450v is only 835mA RCR. Might be a problem.

Thanks Agent24.

Since Jooo was saying that “The ESR doesn't really matter there.”, I have been concentrating in finding a cap with the same or higher ripple current value.

For 100uF 450V, the ripple current data are (all @105C):

The original Samwha HL series is listed as 1200 mA (frequency not listed in the table for caps above 100V, but for smaller voltage ones, the frequency is 100kHz, so I assume the same for 450V)
Datasheet:

Jooo's suggestion of NCC KXG series is listed as 800 mA @120Hz and 1,800 mA@100kHz
Datasheet:

The Nichicon CY series is listed as 836 mA@120Hz
Datasheet:

I have maken the following assumptions. Correct me if I am wrong, as I am a newbie in electronics. Thanks.

First, I make the assumption that the original WL cap is tested @100kHz.
Second, from the datasheet of KXG, I have noticed that the ripple current jumped at least double when testing frequency changed from 120Hz to 100kHz (800 mA @120Hz to 1,800 mA@100kHz), so I assume that the CY series ripple current will be at least 2 times of 836 mA = 1672 mA @100kHz. Since @120Hz, the ripple current value of CY is higher than KXG, so I assume @100kHz CY's value is higher than 1,800 mA too.

Based on the above assumptions and from the datasheets:

- CY has a higher ripple current than KXG (836 mA @120Hz VS 800 mA @120Hz)
- CY has a higher load life than KXG (10000-12000 vs 8,000- 10000 hrs)

The things that I have no idea are:

- Is CY as good as KXG in term of reliability (which brand of cap is better) ?
- KXG is listed as “non solvent resistant type”, is CY the same type? And does that make any different?

Thanks for your input and time.

[Agent24]

Re: Need advice in finding low impedance repalcement capacitor

Good catch. Yes, the different frequency will make a difference. CY datasheet says to double the RCR when going from 120Hz as measured to 100kHz. So yeah, that one would be fine (On paper).

I haven't heard of CY before, KXG is known good but probably either one will work fine. In any case, both are surely better than a Samwha.

The non-solvent resistance means you can't wash the board with solvents to clean flux off afterwards, but since you're not a factory and you're not running the entire board through a wash cycle, it doesn't matter.

[fun148]

Re: Need advice in finding low impedance repalcement capacitor

Thanks Agent24. I now can order the capacitors and see if my TV can be saved.