Viewsonic 2235 switched off by itself

[trgdai]

Hi everyone,

I have a video problem with my Viewsonic 2235 and hope that some of you who have faced the same problem can help me to solve it.

My monitor is working, no display problem. The problem is that after 30 minutes, it is switched off by itself, it is totally off, it does not stay on standby, the PC is still working. I have to wait for 10 minutes and switch the monitor on again. It's working again but for a shorter time. After a few times, the monitor is switched off by itself right after being switched on. Also it looks to be heat up quite fast.

All the capacitors look fine, I have changed randomly half of them, the problem still persists. Does anyone have an idea of what is happening ? Do I need to change all the caps ? I have red that it could be the inverter, but I have also red that if the picture still appears on the screen so the inverter is fine !!

Thank you for your help.

[retiredcaps]

Re: Viewsonic 2235 switched off by itself

All the capacitors look fine, I have changed randomly half of them, the problem still persists. Does anyone have an idea of what is happening ?

1) Are you the original owner of this monitor?

2) How old is it? The manufacturer date is on the back.

3) How many hours do you use it per day?

4) Post clear focused pictures AFTER reading

https://www.badcaps.net/forum/showthread.php?t=1868

5) Please do not post pictures inline.

6) Take your boards to a window on a sunny day, turn flash off, and use macro mode. Take a top down view of all your boards (front and back). Make sure the photo is legible so that we can read the PCB printing clearly. A shutter speed of 1/125 or faster will produce nice clear focus pictures. Try to get a photo that is 2000x2000 resolution or as close as possible.

7) Here is an example of the pictures we want.

https://www.badcaps.net/forum/showpos...94&postcount=1

8) What brand and make are the replacement capacitors that you used?

9) If you turn down the brightness and constrast to 35 and 25, does the monitor stay on longer?

[trgdai]

Re: Viewsonic 2235 switched off by itself

Thank you for replying so fast.
Sorry, I did not have time to take pictures yet or try about the contrast as the monitor is half unmounted.

1) Are you the original owner of this monitor?

Yes I am

2) How old is it? The manufacturer date is on the back.

Bought it since October 2008. I thought the warranty was 1 year but in fact it is 3. Now the monitor is unmounted and I have changed some caps so I think I can forget the warranty !

3) How many hours do you use it per day?

In average 3 to 4 hours a day.

4) Post clear focused pictures AFTER reading

Noted.

5) Please do not post pictures inline.

6) Take your boards to a window on a sunny day, turn flash off, and use macro mode. Take a top down view of all your boards (front and back). Make sure the photo is legible so that we can read the PCB printing clearly. A shutter speed of 1/125 or faster will produce nice clear focus pictures. Try to get a photo that is 2000x2000 resolution or as close as possible.

7) Here is an example of the pictures we want.

https://www.badcaps.net/forum/showpos...94&postcount=1
Link can not be found but it s fine, I think that I know how to do


8) What brand and make are the replacement capacitors that you used?

I don’t know exactly, maybe KMC, is it a brand ?
Six months ago, I have changed on another monitor viewsonic, 2 years old, 2 capacitors KMC (I could see them bad because they were swollen a bit). I was lucky because it was right and my monitor works again until today. The problem was exactly described in the forum. Thank you.

9) If you turn down the brightness and constrast to 35 and 25, does the monitor stay on longer?

I have to try, as I did not use it for a while, maybe it will react
differently already !

Maybe something else useful !!

Just before it happened, Maybe or maybe not, is it a coincidence !?
I plugged the microphone pin of a headphone/microphone set in the audio jack of the computer and the monitor went black, it was switched off by itself.

So I restarted the computer, I plugged another microphone pin of another headphone/mic set, and the same thing happened.

I don t know if the all the mic set were fine, I was looking for one working microphone.

Is my case unusual as I don t get many suggestions!

Thank you

[retiredcaps]

Re: Viewsonic 2235 switched off by itself

4) Post clear focused pictures AFTER reading

Noted.

We will await for pics.

8) What brand and make are the replacement capacitors that you used?

I don't know exactly, maybe KMC, is it a brand ?

Please post a pic of these caps.

Just before it happened, Maybe or maybe not, is it a coincidence !?
I plugged the microphone pin of a headphone/microphone set in the audio jack of the computer and the monitor went black, it was switched off by itself.

So I restarted the computer, I plugged another microphone pin of another headphone/mic set, and the same thing happened.

I don t know if the all the mic set were fine, I was looking for one working microphone.

It is possible that plugging in the headphone/mic shorted out something?

Anyways, post pics first. Afterwards, we can suggest test points for your multimeter.

[trgdai]

Re: Viewsonic 2235 switched off by itself

Hello,
1st question, why can t I see/read my question in the forum 'Troubleshooting computer displays' ?
I can see it by googling : 'viewsonic 2235 switched off by itself'. So I can read only my message.

Thank you

[trgdai]

Re: Viewsonic 2235 switched off by itself

Hello again,

First, Your question : It is possible that plugging in the headphone/mic shorted out something?
I don t know, i dont dare to plug the sets in another computer. So I have to buy a new set and try again on the 'problem' computer ?


Second, I m trying to add some pics, and hope they re clear enough.
I labeled all what i can. Sorry for the rest.

Thank you

[FIXITNOW]

Re: Viewsonic 2235 switched off by itself

only seen 1 of these
I replaced 7 electrolitic capacitors use low esr versions
the 400v 120uf should be ok

[retiredcaps]

Re: Viewsonic 2235 switched off by itself

Second, I m trying to add some pics, and hope they re clear enough.
I labeled all what i can.

Some suggestions that may solve your problem.

1) Capxon caps are not known to be high quality caps. The 3 unchanged caps are all Capxon and these 3 provide voltage to the inverter section of the board.

Change out the Capxon with some quality low ESR caps.

2) You may want to refresh/reflow the solder on the inverter transformer (the 2 black/yellow square boxes next to the ccfl connectors) pins.

[seanc]

Re: Viewsonic 2235 switched off by itself

The 5th picture, that capacitor with a Panasonic T style vent, it looks wrong, the sleeving is wrong.
Whether it's pretending to be a Panasonic or something else, I'm not sure, but I am dubious.

[trgdai]

Re: Viewsonic 2235 switched off by itself

Thank you very much. I am going to try your suggestions and come back to you.