ASUS vw246h no video

[alexsquared]

I have one of these monitors and it has no video on any input. It powers on but there is no signal. Any thoughts?

[lcdman]

Re: ASUS vw246h no video

Hello alexsquared,

Take the monitor apart,carefully. The second thing you should take good pictures of both circuit boards and post them using the "manage attachments" button under advanced on this site. That way the more experienced members can help steer you in the right direction. My guess is the main (video) board or the screen or even the screen's bulbs are your issue. Are you saying that the power led is lit? I say that because you said that the power comes on.

Good Luck,
lcdman

[alexsquared]

Re: ASUS vw246h no video

I know it powers on because it shows the asus logo on startup. It also shows the menu. It just doesn't show any video sources. Thank you!

[budm]

Re: ASUS vw246h no video

Can you see on screen user setup menu?

[alexsquared]

Re: ASUS vw246h no video

Can you see on screen user setup menu?

Yes

[budm]

Re: ASUS vw246h no video

OK, your inverter and T-CON and screen are OK, we need to check the protection diodes for the VGA/DVI input pins next. Can you post good pictures of the logic board, good closed up around the VGA/DVI input also so I can see the surface mounted diodes.

[alexsquared]

Re: ASUS vw246h no video

I'll try to open up the unit this weekend. Thanks for the input.

[2andrewd]

Re: ASUS vw246h no video

PLEASE post pictures of the logic board! I have one of these that has been kicking around for quite some time due to some damage to the pcb (it would be GREAT if you could check continuity at a few points so I can get past damaged vias on the 22uf caps and the one 10uf.) and schematics for this model have yet to be found. i have them for the 22" and the 26" models but the 24 is neither here nor anywhere far as I can google.

[alexsquared]

Re: ASUS vw246h no video

OK, so I finally got a chance to open this bad boy up. Took some good (i believe) pictures of the main board. I did see some discoloration on the PCB that I'll highlight in the pics (pics with MU at end are the marked up ones). Any insight would be greatly appreciated.

[alexsquared]

Re: ASUS vw246h no video

Were these the needed pictures?

[budm]

Re: ASUS vw246h no video

Can you please take the DC voltage readings of the two 3-pin voltage regulator IC on the top left corner of the board with reference to ground?

[alexsquared]

Re: ASUS vw246h no video

Pardon my ignorance, but I'm assuming you are referring to the IC's I have attached and circled on this post? If so, any indication as to which pin I need to check voltage at, and also helpful would be a recommendation as to where to get a good ground reference. Lastly, I'll have to double check that I can get all ribbon and other cables connected (so I can power on for voltage readings) and still have access to the upper side of the IC for these readings. Any suggestions here would be greatly appreciated.
Part of me is wondering if the best solution would be to obtain a new main board (http://www.shopjimmy.com/asus-5e-0nc...for-vw246h.htm ...I know they are out of stock), however, I would love to fix this on the cheap if possible.

[budm]

Re: ASUS vw246h no video

Yes those are the one. Just report the reading on all 3 pins (just make it as 1, 2, 3)

[alexsquared]

Re: ASUS vw246h no video

any pointers on where to find a reference to ground?

[lcdman]

Re: ASUS vw246h no video

Hello,

I would put your black meter probe on the tab. And then your red probe on each of the other leads and record the readings. If the readings don't work out then reverse the test leads when taking your readings.

Take Care,
lcdman

[2andrewd]

Re: ASUS vw246h no video

Any of the points within the yellow perimeter i've drawn will be tied to ground, place your com probe (black) across a few of those carefully and with your meter on dc voltage take a reading of each of the pins on both ic's, start at the top and record them as...

3-
2-
1-

1-
2-
3

[alexsquared]

Re: ASUS vw246h no video

Sorry for the delay, just got a chance to do this. Please see below. From top down:
3- 1.208 v
2- 0v (no visible connection to pcb)
1- 3.317 v

1- 2.068 v
2- 3.317 v (no visible connection to pcb)
3- 5.053

[alexsquared]

Re: ASUS vw246h no video

Do these look ok?

[budm]

Re: ASUS vw246h no video

This one needs verification. Is 3 the top pin? What voltage do you get (if 3 is the top pin) when you measure between pin 1 and 2. It looks like 1.2V regulator.
3- 1.208 v
2- 0v (no visible connection to pcb)
1- 3.317 v

This one shows OK, 1.25V vref + 2.068 = 3.318V
1- 2.068 v
2- 3.317 v (no visible connection to pcb)
3- 5.053

[2andrewd]

Re: ASUS vw246h no video

Those are 2.5v and 3.3v regulators respectively. I'm assuming pin 1 is the input and pin 3 is the out..