ASUS VH222 has no image

[ucdzombie]

ASUS VH222 23" LCD screen. Powers on, but has no image. Tried the flash light trick and saw faint image. So either inverter is bad or back light is bad. I'm suspecting the inverter because there's a discoloration spot on the power board. Please take a look at the picture with the voltage reading. Any help will be appreciated!

[newtothis]

Re: ASUS VH222 has no image

Can you take a pic of the connector that goes to the logic board so we can see the silk print please.

[budm]

Re: ASUS VH222 has no image

If you look at the screen in the dark room, do you see the backlights flash on for seconds?

[ucdzombie]

Re: ASUS VH222 has no image

Can you take a pic of the connector that goes to the logic board so we can see the silk print please.

Apologize in advance because I'm not sure if this is what you're looking for. I'm a complete dummy. There're two connectors

[ucdzombie]

Re: ASUS VH222 has no image

If you look at the screen in the dark room, do you see the backlights flash on for seconds?

I don't remember seeing it flash at all. When it turns on, there's no back light because the color of the screen doesn't change to dark bluish grey. I will check again today.

[selldoor]

Re: ASUS VH222 has no image

Could easily be the inverter transformer.
Can you see the numbers on it?


May be one of these?
http://www.lcdparts.net/TransformerD...ProductID=3699

To test - no power to board meter on ohms 2000 test S1 to S2 and S3 to S4

[ucdzombie]

Re: ASUS VH222 has no image

Could easily be the inverter transformer.
Can you see the numbers on it?


May be one of these?
http://www.lcdparts.net/TransformerD...ProductID=3699

To test - no power to board meter on ohms 2000 test S1 to S2 and S3 to S4

OK I got the reading:

S1 to S2 has 500 ohms, S3 to S4 has no reading at all. I didn't de-solde the transformer. I tested by touching the leads on the back of the board. Did I do it correctly?

[ucdzombie]

Re: ASUS VH222 has no image

I don't remember seeing it flash at all. When it turns on, there's no back light because the color of the screen doesn't change to dark bluish grey. I will check again today.

OK guys, another update! Today I turned it on, the LCD screen actually turned on. I saw the ASUS Logo, and I could see the desktop for about 1 second before it went dark. Power light stays on (blue).

[ucdzombie]

Re: ASUS VH222 has no image

If you look at the screen in the dark room, do you see the backlights flash on for seconds?

Today I turned it on, the LCD screen actually turned on. I saw the ASUS Logo, and I could see the desktop for about 1 second before it went dark. Power light stays on (blue).

[budm]

Re: ASUS VH222 has no image

OK, then check the transformer high voltage windings resistance, you can have bad lamps also, you may have get a couple test lamps or make some otherwise you can spend a lot of time trying to fix the board when you may have lamps problem, need to narrow that down.
https://www.badcaps.net/forum/showth...er+testing+cfl

[selldoor]

Re: ASUS VH222 has no image

budm - looks like his inverter transformer is shot - if he is testing it correctly.
500 ohms and 000 ohms!! post 7

ucdzombie - we really need the part number off the transformer but it doesnt
look good.
If you cant read the number (even parts of it might help)
then a picture of the back of the board where the transformer is so we can see where you measured. Sometimes there is lacquer on the joints try again
making sure you are down to metal.

[budm]

Re: ASUS VH222 has no image

Sorry, I missed that post.

[ucdzombie]

Re: ASUS VH222 has no image

budm - looks like his inverter transformer is shot - if he is testing it correctly.
500 ohms and 000 ohms!! post 7

ucdzombie - we really need the part number off the transformer but it doesnt
look good.
If you cant read the number (even parts of it might help)
then a picture of the back of the board where the transformer is so we can see where you measured. Sometimes there is lacquer on the joints try again
making sure you are down to metal.

Here's the part number I think:


http://www.ebay.com/itm/Inverter-Tra...-/261267004394

And the back of the board:


Also, remember I said that there's a discoloration spot on the board where those two Zeners are. They're weird. One side has 15v and the other side has 0v (as shown in the first post).

Thank you everyone for being so supportive!!!

[selldoor]

Re: ASUS VH222 has no image

Remove it and test again check the winding is not snapped just by the pin - if it is it may be re-attached


I would get one ordered from the link you have found.
I dont know about the zeners -perhaps they just run hot - budm would know better.
Perhaps upgrade any caps associated will help them run cooler.

[Davi.p]

Re: ASUS VH222 has no image

The not turning on of the backlights and the lack of a voltage on that ferrite seems to me a strange behavior for a normal transformer or ccfl failure, can you post a picture of the downside, 'cause is needed to watch at wich point to test for the psu outs.

[ucdzombie]

Re: ASUS VH222 has no image

Remove it and test again check the winding is not snapped just by the pin - if it is it may be re-attached


I would get one ordered from the link you have found.
I dont know about the zeners -perhaps they just run hot - budm would know better.
Perhaps upgrade any caps associated will help them run cooler.

Updates! The transformer enjoyed a nice barbecue and S4 was burned beyond recognition. Look at the charcoal on the board. So I'm wondering, what if i just solder another wire onto S4 and make a new pin?

[ucdzombie]

Re: ASUS VH222 has no image

The not turning on of the backlights and the lack of a voltage on that ferrite seems to me a strange behavior for a normal transformer or ccfl failure, can you post a picture of the downside, 'cause is needed to watch at wich point to test for the psu outs.

What do you mean by the downside? You mean the other side of the PSU?

[Davi.p]

Re: ASUS VH222 has no image

i mean "lower side" but now you have found the problem.. don't photograph..

[selldoor]

Re: ASUS VH222 has no image

WoW! not seen one do that before - if you can find the end of the wire, you can try and fix it. To solder you will need to scrape the laquer insulation off the end of the wire. before you move on to making a pin test the resistance again it needs to be within 3 % of the other one so 485 to 515ohms if the s1 to s2 is correct..

[budm]

Re: ASUS VH222 has no image

The wire will be hair thin, it is going to be difficult job since the wire will be too short to reach the post.
You will also have to remove the carbonized section of the board since carbon conducts electricity especially it is in the high voltage section that can be as high as 1500V or more.