Doublesight DS-240WB turns off after 5sec-5min

[thepenguin99]

So this is my first attempt at fixing a monitor. I thought about taking it somewhere to have it fixed. I decided would rather learn how to do it myself and maybe acquire some new tools in the process.

As my title states the monitor will turn on every time but turns back off after anywhere from a few seconds to a few minutes. The interval seems to be longer if you let it sit a while before cranking it back up. My initial youtube video search led me to believe I had a decent chance of opening it up and seeing a cap that was obviously bad. Needless to say, that didn't happen. I guess what I am looking for now is a little direction from someone.

[tom66]

Re: Doublesight DS-240WB turns off after 5sec-5min

I would say you are dealing with bad caps, even if none are bulged.

Can you take a picture of the insides of the monitor?

[thepenguin99]

Re: Doublesight DS-240WB turns off after 5sec-5min

Here are some shots.

[tom66]

Re: Doublesight DS-240WB turns off after 5sec-5min

Does this thing have an external power brick? Can't see anything resembling a power supply in it. If so, that would be what I would check - it's probably got bad caps but if it's got a standard 5mm jack plug then you can get them for cheap enough on eBay.

[thepenguin99]

Re: Doublesight DS-240WB turns off after 5sec-5min

It has a power brick but I swapped it out with a known good one and got the same issue.

[tom66]

Re: Doublesight DS-240WB turns off after 5sec-5min

It has a power brick but I swapped it out with a known good one and got the same issue.

Hmm. Check the voltages at the jack connector just to make sure they stay stable when it goes off.

[thepenguin99]

Re: Doublesight DS-240WB turns off after 5sec-5min

I just realized that I didn't accurately describe the issue as well as I should have. It doesn't actually turn off but it ceases to display video. The power button stays lit. You can hit the input button to change from DVI to VGA then back to DVI and it will display again for a few seconds.

Also, I will check the voltage today when I get a chance.

[tom66]

Re: Doublesight DS-240WB turns off after 5sec-5min

I just realized that I didn't accurately describe the issue as well as I should have. It doesn't actually turn off but it ceases to display video. The power button stays lit. You can hit the input button to change from DVI to VGA then back to DVI and it will display again for a few seconds.

Do the backlights go off when this happens?

[thepenguin99]

Re: Doublesight DS-240WB turns off after 5sec-5min

Yea, the screen goes black

[tom66]

Re: Doublesight DS-240WB turns off after 5sec-5min

Yea, the screen goes black

Since it has speakers, have you tried feeding in an audio source and seeing if it continues working?

[thepenguin99]

Re: Doublesight DS-240WB turns off after 5sec-5min

I have not. I did just get finished checking the power brick and it remains constant whether the screen stops displaying or not. Which is good because I thought I had killed it on accident.

[tom66]

Re: Doublesight DS-240WB turns off after 5sec-5min

I have not. I did just get finished checking the power brick and it remains constant whether the screen stops displaying or not. Which is good because I thought I had killed it on accident.

That's good. I think the problem is in the inverter, but checking for sound will verify that.

[thepenguin99]

Re: Doublesight DS-240WB turns off after 5sec-5min

I am currently charging my touchpad so I can output audio off it to the monitor. Will give it a shot in a hour or two. I have never actually used the speakers so I really have no idea if they work at all. It is probably safe to assume they do though since I have had the monitor since it was new.

[thepenguin99]

Re: Doublesight DS-240WB turns off after 5sec-5min

The speakers do indeed continue to work after the screen goes blank. I also realized why I never used the speakers.....so terrible.

[tom66]

Re: Doublesight DS-240WB turns off after 5sec-5min

The speakers do indeed continue to work after the screen goes blank. I also realized why I never used the speakers.....so terrible.

That's good then. One more check: Shine a torch/flashlight at the screen. When the screen goes dark, can you still see a picture?

[thepenguin99]

Re: Doublesight DS-240WB turns off after 5sec-5min

I tried shining a small led flashlight at it while getting rid of as much light in the room as I could and I cannot see a picture.

[tom66]

Re: Doublesight DS-240WB turns off after 5sec-5min

I tried shining a small led flashlight at it while getting rid of as much light in the room as I could and I cannot see a picture.

Actually, it's better to do it with more natural light. The flashlight trick does not work all the time and it varies depending on the LCD panel.

Is there a connector going from the main board to the inverter? The inverter is the board with the pink and white wires coming out of it.

[thepenguin99]

Re: Doublesight DS-240WB turns off after 5sec-5min

I tried again with more natural lighting and a better flashlight with the same results. I can't see anything.

There is a connector from the main board to the inverter board. I shot a couple pics of it.

[tom66]

Re: Doublesight DS-240WB turns off after 5sec-5min

Okay, I've highlighted a test for you to do.

While monitor is working probe for voltage between the red and black points.

When monitor goes off check the voltage again.

If it significantly changes, the problem is probably on the main board. If not, the problem is probably with the inverter.

[thepenguin99]

Re: Doublesight DS-240WB turns off after 5sec-5min

Ok, I had 24v when I checked the power brick. I seem to have 23.5 to that point when the monitor is on. When it goes off I have 24v again. I am not using a digital multimeter so the measurements may not be as exact as they would be otherwise.