Asus VW246H will not power on

[budm]

Re: Asus VW246H will not power on

I just got the PM.
Check the resistance of resistor R615, it should be less than 1 Ohm.

BTW, Can I get good clear hi-res straight shots pictures of the whole top side and bottom side of the power supply board? The one in your post #63 I cannot use it to trace the circuits.

[swofra]

Re: Asus VW246H will not power on

Ok, replaced fuse F601 and now have 123VAC at the inner terminals of the Bridge Rectifier (BR) and 159VDC at the outer BR terminals. Big Brown cap also has 159VDC. With the logic board plugged into the main board only (meaning the logic board isn't plugged into the monitor buttons). I tested the green (soldered) side of the board CN 701 connection and didn't get VDC readings on any of the solder points that corresponded to pin position.
First, I just want to make sure that's a valid way to test CN701, and second, if I'm not getting power there, what else could be the problem/test next?

thanks!

[budm]

Re: Asus VW246H will not power on

Hey all,
Total noob, trying to figure things out as well. No power, no standby light for me either. Based on board markings, looks like I have a slightly older power board version so I'm posting board pics as I don't know exactly what else is different than OP's pics.

Here is what I have:
- Fuse F501 doesn't register any ohms (OL) with power off, however when plugged in and one lead is placed on the ac terminal and one on the BR ac input I register 122V (I'm from the US). Does this mean power is going through and the fuse is actually ok?

The Bridge rectifier's DC contacts register 10V DC one time and then the next time I plug it in they could be as low as under 2 DC.
I’ve tested the bridge rectifier in diode mode and it reads ~.5 at all three points, and zero if i reverse the probes.

I get no power at the CN701 connection.

Where do I need to go from here?

Thanks!!

1) That fuse is blown if your Ohm meter is showing 'OL', it should show the same resistance reading when you touch the two probes of your Ohm meter together.
2) When you measure between the two inner legs of the bridge rectifier should shows 120VAC if the fuse is NOT blown.

[swofra]

Re: Asus VW246H will not power on

Anybody had a chance to review and/or have any insights?

[swofra]

Re: Asus VW246H will not power on

Sorry, fuse I referred to in earlier post is actually F601

[swofra]

Re: Asus VW246H will not power on

Hey all,
Total noob, trying to figure things out as well. No power, no standby light for me either. Based on board markings, looks like I have a slightly older power board version so I'm posting board pics as I don't know exactly what else is different than OP's pics.

Here is what I have:
- Fuse F501 doesn't register any ohms (OL) with power off, however when plugged in and one lead is placed on the ac terminal and one on the BR ac input I register 122V (I'm from the US). Does this mean power is going through and the fuse is actually ok?

The Bridge rectifier's DC contacts register 10V DC one time and then the next time I plug it in they could be as low as under 2 DC.
I've tested the bridge rectifier in diode mode and it reads ~.5 at all three points, and zero if i reverse the probes.

I get no power at the CN701 connection.

Where do I need to go from here?

Thanks!!

[magicsmoke12]

Re: Asus VW246H will not power on

..is any regulator (3.3V and 1.2V) getting hot ? If not, did you try to give a look to the capacitors ?

Regulators not getting hot, didn't see any caps looking damaged.

Had it unplugged and then tried plugging it in one last time and I now have a different problem:
When I turn it on now I get backlight (no image displayed) for about 2 seconds, then off, then another 2 seconds of backlight then it switches to standby.
If I click the input select I get backlight for another couple of seconds then back to standby, even with a computer connected.

I can power off with the power button and when I switch on again the same thing repeats.

Looking less fixable by the day now.

[lukjoly]

Re: Asus VW246H will not power on

Hi all,

Similar problem here with my VW246H.
For quite a while it's had problems with turning back on when switched off (either by the power button or the mains).
Dealt with it for a while by just leaving it on standby all the time but finally had to turn the mains off and now can't power up.

When I plug in the AC cable there is a very brief flicker on the power LED but nothing else, did the tests from above and am getting 5v through the same pins as others to the mainboard, both 3.3V and 1.2V regulators test ok.

Any other thoughts? It's a pretty old monitor at this point and probably just going to replace but thinking it might be worth a shot if it's an easy fix.

..is any regulator (3.3V and 1.2V) getting hot ? If not, did you try to give a look to the capacitors ?

[magicsmoke12]

Re: Asus VW246H will not power on

Hi all,

Similar problem here with my VW246H.
For quite a while it's had problems with turning back on when switched off (either by the power button or the mains).
Dealt with it for a while by just leaving it on standby all the time but finally had to turn the mains off and now can't power up.

When I plug in the AC cable there is a very brief flicker on the power LED but nothing else, did the tests from above and am getting 5v through the same pins as others to the mainboard, both 3.3V and 1.2V regulators test ok.

Any other thoughts? It's a pretty old monitor at this point and probably just going to replace but thinking it might be worth a shot if it's an easy fix.

[lukjoly]

Re: Asus VW246H will not power on

Hi Luke
The second regulator if my memory serves me right takes the 3.3V and puts out 1.2V that the push buttons use. So if the 3.3V regulator isn't working you will not get the 1.2V.

Hi, thanks for reply, indeed in a rare moment of functioning of the 3.3V reg I was able to discover that that chip put out 1.2V .... at moment I've ordered abroad the compatible parts (5A 3.3V regulator and 1.3A 1.2V regulator) plus all the 6 caps installed on the board just to make sure. Waiting delivery.
thanks
Luke

[Jagdtiger777]

Re: Asus VW246H will not power on

Hi folks,
I'm facing the same issue with the Asus VW246H monitor. Power on works only every now and then. I followed the indications in this forum and the conclusion is that the voltage regulator (G1084-33) sometimes gives 3.3V sometimes does not hence I'm going to replace it with a similar chip easier to find on the market (AP1084-33) but...... I'm wondering if also the other power chip marked (see pict) 210138LA M819272B could be part of the power failure and so worth of replacing. Though, after extensive research I've not been able to identify this part.
Any hint will be greatly appreciated.

Thanks
Luke

Hi Luke
The second regulator if my memory serves me right takes the 3.3V and puts out 1.2V that the push buttons use. So if the 3.3V regulator isn't working you will not get the 1.2V.

[lukjoly]

Re: Asus VW246H will not power on

Hi folks,
I'm facing the same issue with the Asus VW246H monitor. Power on works only every now and then. I followed the indications in this forum and the conclusion is that the voltage regulator (G1084-33) sometimes gives 3.3V sometimes does not hence I'm going to replace it with a similar chip easier to find on the market (AP1084-33) but...... I'm wondering if also the other power chip marked (see pict) 210138LA M819272B could be part of the power failure and so worth of replacing. Though, after extensive research I've not been able to identify this part.
Any hint will be greatly appreciated.

Thanks
Luke

[frica]

Re: Asus VW246H will not power on

+1

[Hammer034]

Re: Asus VW246H will not power on

Thanks to jadgtiger777 my monitor is workin again.
It was the g1084-33 regulator on the mainboard (logic)
The regulator wasnt puting out any voltage.

[Hammer034]

Re: Asus VW246H will not power on

Sorry I forgot I had a photo.

Thanks.
Didnt check it yet.
Plus I been looking for that chip but havent found one yet just in case thats it.

[Jagdtiger777]

Re: Asus VW246H will not power on

Sorry I forgot I had a photo.

[Hammer034]

Re: Asus VW246H will not power on

Hi Hammer034,
I just fixed my Asus VW246H. It had periods when it would not turn on until it had a rest for a few days. It finally failed to turn back on after a black out in our area. I checked the power supply board and had the same 5v DC voltages at the connector to the main board as you indicated. On the main board I found a 3.3V regulator (G1084-33) this had 5v coming in but no 3.3v going out. So after replacing this regulator my monitor is working.
I hope this will help you.
Cheers.

Thanks for the reply.
I will look into it.
You say this is on the mainboard and not the power supply board,correct.
I will update after checking.
thanx

[Jagdtiger777]

Re: Asus VW246H will not power on

Hi Hammer034,
I just fixed my Asus VW246H. It had periods when it would not turn on until it had a rest for a few days. It finally failed to turn back on after a black out in our area. I checked the power supply board and had the same 5v DC voltages at the connector to the main board as you indicated. On the main board I found a 3.3V regulator (G1084-33) this had 5v coming in but no 3.3v going out. So after replacing this regulator my monitor is working.
I hope this will help you.
Cheers.

[Hammer034]

Re: Asus VW246H will not power on

Update on pin voltages while connected to mainboard.

Pins 7 and 8 = 5 volts DC
Pins 10 and 11= 5.38 volts DC

The numbers in previous post were with power supply disconnected from main board.

Thanks.

[Hammer034]

Re: Asus VW246H will not power on

Hi all.
Long time lurker first time poster.
Have same monitor as above with same problem.
Unplugged and will not power on again.Monitor did this back in july but after sitting for a week it worked again until now when i had to kill breakers to replace outlet.
When I plug it in, power light will flash once and thats it. if i unplug and replug right away it will not flash. If I wait a minute to replug it will flash again.
I replaced all caps with new panasonics even the main big cap and it still does the same thing.
I have 157 volts on big cap (Im in the USA).
I have checked all diodes and resistors(still in circuit, ya i know) and they appear ok.
I have not pulled and checked the mosfet(Q601) yet.
On the 12 pin connector I have some strange voltages when checking to ground lug on board.
Pin numbers and voltages below.
1 45v ac
2 45v ac
3 unused
4 unused
5 45v ac
6 45v ac
7 45v ac
8 45v ac
9 unused
10 45v ac
11 45v ac
12 6.5v ac
I have nothing as far as DC volts on any pins.
Can any of you gurus advise me on what I should check next.
My father was an electronics engineer and I worked in his place for a while so I do have a little knowlage.
I am also certified in soldering so thats not an issue.
He passed away a few years ago and i have nobody to repair this for me anymore.
Thanks for any help or insight you can give me.
Here are some pics of board i replaced the caps.