Replace the big cap in a Samsung monitor

[ckrtech]

Hey guys -

A few years ago (goodness), I recapped the power board of a Samsung 27" monitor by replacing all electrolytics except for the big guy (450wv 150uf) made by... Samwha. Details are https://www.badcaps.net/forum/showthread.php?t=42647

The monitor came back to life and continues working to this day, however it requires time to warm up. It turns on flickers every few seconds 5 seconds, 10 seconds, 1 second, 1 second...just randomly until it finally stabilizes.

I assume that I just need to replace the main cap, and I have just been lazy for... 4 years.

But I thought I would ask:

1: Do you agree that this is probably "it?"
2: What do you recommend for a replacement?

I have the monitor open and the power board removed right now because I am ordering caps for a different project and figured I would add this one to the mix.

Thanks!

[ckrtech]

Re: Replace the big cap in a Samsung monitor

Looks like this might be the datasheet: https://cdn.badcaps-static.com/pdfs/...7dd4e28424.pdf

[stj]

Re: Replace the big cap in a Samsung monitor

what caps did you use as replacements before?
they could be gone again.

[R_J]

Re: Replace the big cap in a Samsung monitor

I doubt its the main cap, What stj suggests could be the issue or something unrelated, at least post the model number. or pictures of the boards

[ckrtech]

Re: Replace the big cap in a Samsung monitor

what caps did you use as replacements before?
they could be gone again.

Panasonic FM. I think they should be OK. I believe the flicker/warm-up issue remained after replacing those caps, but prior to replacement... the monitor wouldn't turn on.

The input board uses SMD caps. I haven't removed it to take a look.

The - what I assume to be - scan board on the side of the display uses 6 caps in groups of three. I did not replace these this first time... (pic included)

Samsung 275T Plus monitor. Acquired in 2008, I believe.

[stj]

Re: Replace the big cap in a Samsung monitor

i bet that's the backlight invertor.
that symbol is SamYoung, they look like good caps, but the age is a problem.

[ckrtech]

Re: Replace the big cap in a Samsung monitor

I am about to order some replacement caps for a old Sony Trinitron TV, so I figured I would finally lop in some for this monitor. I suppose I could get 6 for the invertor.

The flickering was the first thing to start happening - and that was maybe 2011-2012 - only 3-4 years after I purchased it. It gained in frequency of occurance until in 2014 it would sometimes just not turn on. After the power board recap (minus the 450v), it came back to life but would still have the flicker.

Do you have a recommendation for a replacement series that can hit or ballpark the NXH with .056 impedance and 945 mA @ 100kHz? The lead spacing and even height have some wiggle room due to the mounting style, but my filtering on digikey seems to be too tight, perhaps.

[stj]

Re: Replace the big cap in a Samsung monitor

panasonic FR of course

220/35
950mA .056ohms
8mm x 11.5mm

[ckrtech]

Re: Replace the big cap in a Samsung monitor

Dang. Digikey doesn't carry that one, but Mouser does. I guess I could order from Mouser.

I never really use the capacitance testing on my multimeter, but I used it on the large 150uf cap with it out of circuit. It hits around 28 nf.

Package works well with this one, but the ripple current isn't quite as high as the Sanwha claim - https://www.mouser.com/ProductDetail...2b7y2WQz2dY%3d

[ckrtech]

Re: Replace the big cap in a Samsung monitor

Oops. Didn't consider *shorter* ones.

https://www.mouser.com/ProductDetail...2bZaeG26VG4%3d

Looks like that would work.

[ckrtech]

Re: Replace the big cap in a Samsung monitor

Caps arrived. Soldered in. Samsung 275T Plus *definitely* needed to have the 450WV 150uf cap replaced.

No flicker. Good as new.

Thanks for the assistance.