AOC F22+ weird symptoms

[Half-Saint]

Hi!

I have here an AOC F22+ monitor that powers up but doesn't display a picture for a while. First it starts with displaying a couple of horizontal dotted lines then it springs up to life. From time to time the lines show but it generally works after that.

I disassembled the screen and the caps look OK. They used Elite ED caps:
1x 1000uF 25V
1x 22uF 50V
2x 680uF 25V
1x 1000uF 16V
1x 470uF 16V

What could be the problem, if not the caps?

Cheers,
SainT

[selldoor]

Re: AOC F22+ weird symptoms

Please can you update your profile with country and voltage so we know what we are dealing with. good clear pictures of boards would help. If that 22uf 50v is on the primary
/hot side it may be the start up cap. Elite are not aptly named.

[Half-Saint]

Re: AOC F22+ weird symptoms

Thanks for reminding me, fixed my profile :-)

Here's also a pic of the PCB:

[selldoor]

Re: AOC F22+ weird symptoms

Ok think C908 is the start up cap - the small one just behind the BIG one is it the 50v
22 uf ?? - May not be a power problem at all what you can do is try heating the caps before switching on to see if it makes any difference.
Does the delay start occur if when its on you switch it off and back on again.

There is a lead from the main board to the panel lvds Can you remove clean ( if its a flat ribbon type) and reseat. It could also be voltage regulators on the main board
Can you post a picture of that

[Half-Saint]

Re: AOC F22+ weird symptoms

To pre-heat the caps, I'd have to bring a hair dryer from home :-) I'll try switching it off and back on again after it's been on for a while.

Flat cable to the LCD can be removed no problem.

UPDATE: turned the monitor on and off just fine three times in a row. After the 4th time, it wouldn't display anything anymore just very very thin lines, barely visible. Maybe it's not the power board after all.

[Half-Saint]

Re: AOC F22+ weird symptoms

Here's a pic of the other PCB :-)

[selldoor]

Re: AOC F22+ weird symptoms

Pic is a little too blurred I can only suggest you try some new caps on it or at least the one at the top right.
If you can get at them when it is powered up you could try and monitor the voltage on it
to see if it changes when the picture changes