ViewSonic VA903b

[CapBlown]

Finally I got one lcd fixed.

When I got this 19" monitor it was totally dead. Trying to turn it on caused just some whining sound and it turned of immediately.

1000uF cap was slightly bulging so I first replaced it only. That was all it took to get it working. Making sure it won't fail again I chose to replace other caps too. Original caps on board were CapXon's.

Of course I had to buy too big 1000uF cap . Luckily I was able to fit it in by putting it on it's side.

[jetadm123]

Re: ViewSonic VA903b

I just repaired several Viewsonic VG930M-3 with the same power supply and the exact same problem. It seems that the 1000uf cap is a common failure for that supply. The original cap was rated at 1000uf 16V, but I installed a 1000uf 25V cap, since that cap was the only one bulged. I also decided to replace the other Capxon caps (which looked ok) as well. You might also want to replace the small 10uf 50v cap as that supplies the startup circuit.

[retiredcaps]

Re: ViewSonic VA903b

Finally I got one lcd fixed.

Trying to turn it on caused just some whining sound and it turned of immediately.

Of course I had to buy too big 1000uF cap .

Good for you. I know the struggles you are having with the other monitor, but I'm sure you are learning a lot.

I have heard that infamous whining twice (the first ever monitor I fixed and then a 22 inch wide LCD). Both were easy cap replacements to get them fixed.

I like stocking 1000uF 16V 10x16mm size caps as they seem to be the ones that fail the most (at least looking through my batch of bad caps).

[CapBlown]

Re: ViewSonic VA903b

I just repaired several Viewsonic VG930M-3 with the same power supply and the exact same problem. It seems that the 1000uf cap is a common failure for that supply. The original cap was rated at 1000uf 16V, but I installed a 1000uf 25V cap, since that cap was the only one bulged. I also decided to replace the other Capxon caps (which looked ok) as well. You might also want to replace the small 10uf 50v cap as that supplies the startup circuit.

Thanks, I did not even notice that cap when I made my purchase list. I will replace it too.

Good for you. I know the struggles you are having with the other monitor, but I'm sure you are learning a lot.

I have heard that infamous whining twice (the first ever monitor I fixed and then a 22 inch wide LCD). Both were easy cap replacements to get them fixed.

I like stocking 1000uF 16V 10x16mm size caps as they seem to be the ones that fail the most (at least looking through my batch of bad caps).

Thanks retiredcaps. Learning is always the coolest part and yes I've really learned alot within last couple of months. I finished my studies in electrical engineering about 15 years ago but I have never worked in this field so I'm a bit outdated. Those times monitors were small CRT's and PC's... hmmm.. they were really slow.

[sliver]

Re: ViewSonic VA903b

I have opened up my Viewsonic VA903b and am looking at the capacitors

You say they can 'bulge'... what does this mean exactly?... bulged on the sides or end?

When I turn on the monitor it makes a whining sound,shows the picture while whining then clicks off/goes to standby. If I turn it on and off several times eventually it stays on... Does this sound like a capacitor issue?

I have attached a photo showing the extent of the end bulging on my capacitors. Any advice appreciated.

[jetadm123]

Re: ViewSonic VA903b

I have opened up my Viewsonic VA903b and am looking at the capacitors

You say they can 'bulge'... what does this mean exactly?... bulged on the sides or end?

When I turn on the monitor it makes a whining sound,shows the picture while whining then clicks off/goes to standby. If I turn it on and off several times eventually it stays on... Does this sound like a capacitor issue?

I have attached a photo showing the extent of the end bulging on my capacitors. Any advice appreciated.

"Bulging" generally means the top portion (although I have seen the sides bulged also) of the cap is no longer flat, but curved like in your photo due to internal pressure buildup. Replace ALL 7 of the caps. You can leave the larger one (lying on it's side) alone, since these rarely fail.

If your next question is "what do I order and how", I suggest Panasonic FM FC series caps from digikey.com if you live in the USA. It should cost under $10 including shipping. Use the directions below:

1) Go to digikey.com

2) In the "parts search" window type: panasonic fm and select "GO" button

3) Under the Capacitor heading select "Aluminum"

4) The first two columns you see are capacitance and voltage. Highlight the value and voltage with your mouse and select the "Apply Filters" button

5) You'll see several selections available. Here's what to look for:


a) Look at the quantity available and minimum purchase. If "0" are available, then there's none to purchase. Some selections require a minumum purchase of a 1000 units, which you also don't want. I think you get the picture.

b) height and diameter. Measure the original caps and compare to what's listed.


6) If your value is out of stock, go back to the beginning and type in "panasonic fc" and go through the same process.

7) During the checkout process select USPS First Class shipping, since this will give the best ship rate.

[retiredcaps]

Re: ViewSonic VA903b

I have attached a photo showing the extent of the end bulging on my capacitors. Any advice appreciated.

C242 is also bulged, but not circled in red.

Like jetadm123 said, replace them all.

[sliver]

Re: ViewSonic VA903b

Thanks for all your advice.

How do I know what size / type of capacitors to get as replacements?

I will try and find a local (NZ based) outlet / website to get replacements. Is there anything I can do to try and prevent this from happening again?

Thanks again.

[sliver]

Re: ViewSonic VA903b

This company has shops locally. Does this catalogue list the appropriate types:

http://jaycar.co.nz/productResults.a...60&keyform=CAT

cheers!

[retiredcaps]

Re: ViewSonic VA903b

This company has shops locally. Does this catalogue list the appropriate types:

http://jaycar.co.nz/productResults.a...60&keyform=CAT

cheers!

From my brief look at jaycar's site, it doesn't seem to carry low ESR caps. These are the recommended ones

https://www.badcaps.net/forum/showthread.php?t=2280

You can buy them from the following websites ...

https://www.badcaps.net/forum/showthread.php?t=613

[pedro]

Re: ViewSonic VA903b

From my brief look at jaycar's site, it doesn't seem to carry low ESR caps.

For the benefit of you guys up top of our planet, Jaycar is an AU/NZ stockist with cap range comparable to the RatShack range.

[momaka]

Re: ViewSonic VA903b

Before you buy new caps, check what brand and series the original caps are and post that info here.

From my brief look at jaycar's site, it doesn't seem to carry low ESR caps.

They do, actually.
http://jaycar.co.nz/productResults.a...16&SUBMIT.y=10
The problem is, they don't say what brand are the caps. Could be any crappy Chinese or Taiwanese brand for all you know. Not to mention they are quite overpriced.
In terms of ESR and ripple, I checked the specs on the 16v, 470uF, and on the 16v, 1000uF caps (since they tend to be common in LCD monitors), and they seem to be on par with United Chemicon KY (which generally are good caps to use in power supplies).
But again, the website doesn't say what brand they are! And you have to check your caps to know what to look for in terms of specs.

[retiredcaps]

Re: ViewSonic VA903b

http://jaycar.co.nz/productResults.a...16&SUBMIT.y=10

Ahh, that extra filter search makes a difference. The pictures for the low ESR show Samxon, but don't say what series.

[sliver]

Re: ViewSonic VA903b

Thanks all for help. I have worked out what I need:

2 x 470uf @ 25v
1 x 470uf @ 10v
2 x 1000uf @ 10v

I have been using the site http://nz.farnell.com to locate panasonic type as recommended above. My question now is if I should be getting ones where voltages is rated as DC or AC. This is for use in the back of the LCD monitor....

Thanks again.

[PlainBill]

Re: ViewSonic VA903b

Thanks all for help. I have worked out what I need:

2 x 470uf @ 25v
1 x 470uf @ 10v
2 x 1000uf @ 10v

I have been using the site http://nz.farnell.com to locate panasonic type as recommended above. My question now is if I should be getting ones where voltages is rated as DC or AC. This is for use in the back of the LCD monitor....

Thanks again.

DC. Panasonic FC or FM series. And make sure the dimensions are correct. It's embarrassing if you can't get the back on the monitor afterward.

PlainBill

[sliver]

Re: ViewSonic VA903b

Thanks for all your help people. My caps arrived today and I attacked the board with a soldering iron and now my monitor works like a charm.

[jetadm123]

Re: ViewSonic VA903b

Thanks for all your help people. My caps arrived today and I attacked the board with a soldering iron and now my monitor works like a charm.

Great work! Another monitor saved from the landfill!

[momaka]

Re: ViewSonic VA903b

Nice!
So, what caps did you end up using?

[ChoiceMad]

Re: ViewSonic VA903b

Great work! Another monitor saved from the landfill!

Here also--well, almost. This monitor began giving me problems when powering it off. Upon pushing the power button the screen would display a fading green and yellow blob (fade to solid white--not black).

The only way to get rid of the solid white screen would be to unplug the power cable.

I purchased from digikey.com and replaced only the one bulging cap.

Based on this thread I know now that I should have replaced all of the caps (with higher voltages perhaps?) because the monitor is now giving the same problem as before.

Thanks for the valuable information here folks!

[retiredcaps]

Re: ViewSonic VA903b

I purchased from digikey.com and replaced only the one bulging cap.

Based on this thread I know now that I should have replaced all of the caps (with higher voltages perhaps?) because the monitor is now giving the same problem as before.

Caps don't have to bulge to be bad. They can have flat tops yet be out uF capacitance or have high ESR (ohm).

You should try and stay with the same uF and voltage if possible. Higher voltage caps can sometimes be larger and may not fit.