Recapping LCD PSU, basic question

[demonfire]

OK, little background:

I got a free LCD monitor from work (ViewSonic VA902b) because it was broke. When I turn it on, it lights for about a quarter to a half a second then goes black, when lit the image is correct.

As the image is correct, I believe the image/input board to be good. As it does light, briefly each time I turn it on I know the backlights are good.

So I suspect it is a bad PSU, and likely bad caps due to the symptoms.

I opened the case and took it apart to find there are four caps on the PSU that are swollen.

Here are the questions:

1. should I go through the trouble of finding the exact same caps (same make/model) or should I go with a better brand? The stocks are Su'scon (read bad things on here about them)

2. If I don't go for the exact caps, I could use help finding suitable replacements....these don't have all the info on them. There is no tolerance or minimum temp markings.

3. If I don't go for the exact caps, can I use caps that are the same capacitance but higher voltage? Or will this cause other issues?

Caps needing replaced:

1x one side says '1000uF 25v ' the other says 'SC 105C 0601(M)'

2x one side says '220uF 25v ' the other says 'SC 105C 0601(M)'

1x one side says '1000uF 10v ' the other says 'SC 105C 0601(M)'

[retiredcaps]

Re: Recapping LCD PSU, basic question

Here are the questions:

1. should I go through the trouble of finding the exact same caps (same make/model) or should I go with a better brand? The stocks are Su'scon (read bad things on here about them)

3. If I don't go for the exact caps, can I use caps that are the same capacitance but higher voltage? Or will this cause other issues?

Caps needing replaced:

1x one side says '1000uF 25v ' the other says 'SC 105C 0601(M)'

2x one side says '220uF 25v ' the other says 'SC 105C 0601(M)'

1x one side says '1000uF 10v ' the other says 'SC 105C 0601(M)'

1) Use brands like Rubycon, Panasonic, or United Chemicon that have low ESR caps.

3) You can use higher voltage caps.

For the above caps, please measure the diameter and height of each cap so they fit when you install the new ones.

Here is PlainBill's instructions on how to choose caps from Digikey ...

https://www.badcaps.net/forum/showpo...33&postcount=2

Recapping may NOT solve your problem, but you must replace the bad caps first. What you are experiencing is what we are calling "two seconds to black".

[retiredcaps]

Re: Recapping LCD PSU, basic question

I opened the case and took it apart to find there are four caps on the PSU that are swollen.

I forgot to mention that caps do NOT have to be swollen or bloated to be bad. Sometimes they may be out of tolerance or have high ESR (ohm reading).

Most on this forum will suggest that you replace ALL the caps regardless especially if they are su'scon.

Additonally, if 4 caps died, the others are likely near death due to age/heat/usage.

[PCBONEZ]

Re: Recapping LCD PSU, basic question

Ideally you check specs on old caps then find a good brand that matches of beats those specs.
Ripple should be the same or higher.
ESR should be the same or less.

I gather you are replacing Su'scon SC series by what you said. ??
Unfortunately that's a dead series. [No data sheets.]

Given no info I would fail-safe and replace them with...
- Output filter caps and/or any 470uF or more
- - - with something comparable to Rubycon ZL or Chemicon KZE [or better]
- The others
- - - with something like Panasonic FC or Nichicon PW [or better]

At a minimum replace all of the same brand that failed from 6.3mm diameter and larger.

[Agent24]

Re: Recapping LCD PSU, basic question

Unfortunately that's a dead series. [No data sheets.]

Not always. Web Archive can be pretty useful...
I've found and attached the Su'scon SC series PDFs

[PCBONEZ]

Re: Recapping LCD PSU, basic question

COOL. - I didn't even think to look there.

The Su'scon SC
1000uF 25v ,, Ripple 1600 ,, ESR 0.060
220uF 25v ,, Ripple 590 ,, ESR 0.180
1000uF 10v ,, Ripple 1000 ,, ESR 0.075

Panasonic FC, Nichicon PW, or better are adequate replacements.
http://industrial.panasonic.com/www-...BA0000CE22.pdf
http://nichicon-us.com/english/products/pdf/e-pw.pdf

.

[demonfire]

Re: Recapping LCD PSU, basic question

I forgot to mention that caps do NOT have to be swollen or bloated to be bad. Sometimes they may be out of tolerance or have high ESR (ohm reading).

Most on this forum will suggest that you replace ALL the caps regardless especially if they are su'scon.

Additonally, if 4 caps died, the others are likely near death due to age/heat/usage.

OK, so all the canister (Aluminum Electrolytic) caps are Su'scon, so I might as well replace them all.....Do I need to replace the disk type ones too? I heard they are more stable so I am not sure....not to mention it takes the cap count from 11 to 26.

So, I am now replacing at least 11 caps, any one-stop shops for all of them which are easy to order from and not too expensive?

I would need:

1x 100uF 450V
1x 1000uF 25V
2x 1000uF 10V
3x 220uF 25V
4x 47uF 25V

[retiredcaps]

Re: Recapping LCD PSU, basic question

Do I need to replace the disk type ones too?

Those are generally okay to leave alone.

I would need:

1x 100uF 450V
1x 1000uF 25V
2x 1000uF 10V
3x 220uF 25V
4x 47uF 25V

Assuming you are in the USA, many here use digikey.com for quick ship and reliable source of caps.

The "big" cap which is 100uF 450V rarely goes bad, but you may as well order it.

After you measure the dimensions of the caps, go back to post #2 and see PlainBill's instructions. He recommends Panasonic FM series of caps. Panasonic FC will work too. And you can mix and match FM and FC if height/diameter are an issue.