Asus VW246H will not power on

[selldoor]

Re: Asus VW246H will not power on

Hmm - a little knowledge...........

Please start again and tell us what is wrong with your set from plug in to switch on to fault status. Leds, screen flashes, sounds etc.

I think you will find FD851 is not mentioned in this thread so we dont even know what you measured there is an FD 851 on the OPs board but it is not a fuse.
Please post pictures of your boards.

[n19htmare]

Re: Asus VW246H will not power on

Hmm - a little knowledge...........

Please start again and tell us what is wrong with your set from plug in to switch on to fault status. Leds, screen flashes, sounds etc.

I think you will find FD851 is not mentioned in this thread so we dont even know what you measured there is an FD 851 on the OPs board but it is not a fuse.
Please post pictures of your boards.

I'm sorry for being vague. Absolutely nothing happens when I plug in the monitor. Pressing the power button does nothing, there is not power at all, no LED status at all.

You are right, I was suspicious that FD851 was a fuse (As it looks like a DIode) I must have read it wrong in the post.

I did locate F851 and I'm reading low ohms at .3, same as the white fuse.

The board is exactly the same as the OP pictured. I will get a picture up when MY camera is done charging.

[selldoor]

Re: Asus VW246H will not power on

Ok Better - and nice picture can you do the other side of the board.
FD851 is a diode and both fuses test good.
Quck test - HIGH voltage so care - Set meter on vDC600 and with just this power supply
board plugged into mains test the voltage on that BIG black Cap C605

[n19htmare]

Re: Asus VW246H will not power on

Ok Better - and nice picture can you do the other side of the board.
FD851 is a diode and both fuses test good.
Quck test - HIGH voltage so care - Set meter on vDC600 and with just this power supply
board plugged into mains test the voltage on that BIG black Cap C605

I will post the picture of the back when I get back.
But the C605 Big dark brown cap, reads 160V (Im in the US, if that matters).

[selldoor]

Re: Asus VW246H will not power on

Voltage on big cap is probably acceptable so now to follow the tests carried out by the first poster. Connect it all up switch on and test the voltages on the
connector to the main board (try the sewing needle trick)
You can also test the voltage on both ends of the F851 fuse - use a ground screw for the black probe.
You can also try the hairdrier trick on the startup cap warm it gently, then
plug in and switch on. (always worth a try)

[budm]

Re: Asus VW246H will not power on

Fuse F851 is for supply B+ to the inverter circuit, it will not stop the main board from functioning if it has gone open circuit. See red lines in the picture.
The power supply may be in the safety shutdown right now or just dead due to bad start up cap or bad SMPS IC, MOSFET, ETC.

[blackbulb]

Re: Asus VW246H will not power on

I just joined today, and while I don't have the same issue as the other two people, I'm still using the same monitor.

My issue was the backpanel, one of the pieces broke loose and only 3 screws could hold the monitor up while mounted. I decided to fix this, did what I needed to do, and was able to mount it. Plugged everything in, monitor turns on, asus screen shows up.

Noticed that the power button won't turn on, unplug it, plug it back in, asus screen shows up, tells me no DVI is connected. Decided to open it again to make sure I didn't mess anything up. I noticed that when I screwed the monitor on the back, I screwed through that cable that is attached to the button circuit board thing.

Pictures show the damage, and for the life of me i don't know what that part is called, and how to get a replacement of a similar length. I'm not sure if I should make a whole topic for this or not, but I figure that technically, my VW246H does not turn on D:

[budm]

Re: Asus VW246H will not power on

It looks like the damaged wire can be splice back together. it only has about 3.3V on those wire so it is not hot voltage, they are just for sending the signals to and from the switch assembly to the main board. You can ask local repair shop to do the work easily.

[blackbulb]

Re: Asus VW246H will not power on

didn't think it would be that simple, thanks for the fast reply!

[UKRobster]

Re: Asus VW246H will not power on

Hi guys, havent logged in for a while an can see this thread has been busy!
Glad my issues have helped out others.

Im gutted to report that my issues have returned.
Since I fixed my monitor at the begining of December it has been functioing fine.
This weekend I needed to turn off my fuseboard to change an electrical socket.
So I powered off the monitor and unplugged the power cable (although it is plugged into a 6 way extension and this was still switched on at the wall).
When i turned the fuseboard on again, plugged the monitor in, and it wouldnt power on. I unplugged it again and left it for about 28 hours. Tried it again and it will still not power on.
I really dont understand why this keeps happening.
I havent taken it to pieces yet, but will do this tomorrow and try changing the start up cap again (have still got 4 left from before).
But has anyone any idea why this happens? I dont need to be having this issue everytime I have to turn the fuseboard off!!

[selldoor]

Re: Asus VW246H will not power on

I have not read back all the thread -perhaps other caps need replacing as well.
Or may be a cold solder joint

Has it been left on standby all the time - that might be enough to just keep a cap operational/joint closed.

Take the back off and pre heat it with a hairdryer again then switch on.

[UKRobster]

Re: Asus VW246H will not power on

Selldoor: Thanks for replying.
It doesnt always get left on standby, but power cable is in extension lead which is always on, perhaps that provides enough to keep cap operational or solder joint warm.
Will try the hairdryer trick, but it will be tomorrow. Will post back with results, thanks again!

[Davi.p]

Re: Asus VW246H will not power on

This don't surprise me much since in the previous reasonings there was a thing that doesn't turn me back, if a leaky cap works better if in higher temp. why pulling the wall plug and leave so for hours makes turn the monitor back to work? If the "startup" cap (why "startup"?) was faulty the monitor doesn't turned on only after unplug, since the psu is always on while plugged and little cap is at a certain temp.
We can explain this because with the monitor plugged but OFF the psu circuit goes into a green mode where the frequency is lower and a low capacity cap makes more fatigue when insead at the pluggin in in the wall the chip is fully on and etc etc...?
Then the new cap is low esr and same capacity/voltage as the old one?
"It doesnt always get left on standby, but power cable is in extension lead which is always on"
What do you mean? Is the mon. been unplugged ever this period?

[UKRobster]

Re: Asus VW246H will not power on

This don't surprise me much since in the previous reasonings there was a thing that doesn't turn me back, if a leaky cap works better if in higher temp. why pulling the wall plug and leave so for hours makes turn the monitor back to work? If the "startup" cap (why "startup"?) was faulty the monitor doesn't turned on only after unplug, since the psu is always on while plugged and little cap is at a certain temp.
We can explain this because with the monitor plugged but OFF the psu circuit goes into a green mode where the frequency is lower and a low capacity cap makes more fatigue when insead at the pluggin in in the wall the chip is fully on and etc etc...?
Then the new cap is low esr and same capacity/voltage as the old one?
"It doesnt always get left on standby, but power cable is in extension lead which is always on"
What do you mean? Is the mon. been unplugged ever this period?

Sorry if my post is a little confusing.
Since early December and initially solving issues, monitor has always been plugged in with power cable, and wall outlet switch has always been 'on'.

Monitor itself is sometimes left on standby (ie: turn off PC but do not touch monitor power button - usually by my girlfriend). But more often monitor is turned off with its power button.


Previous to changing 'startup cap' in December, if I turned off wall outlet power. When turning it back on, monitor would not power on. If I left all cables unplugged overnight, then next day it would power on again. (this is what confuses me, why leave overnight, then work again next day? Doesn't make sense)
That was until December, when it would no longer power on at all.

I changed 'startup cap' and all seemed OK.
Cap used to replace was recommended by 'selldoor' and is the same rating as the one taken out.

I now understand that if monitor is left plugged in and wall outlet 'on' that there is a small current passed through PSU. Therefore monitor functions day after day.

I will be trying a hairdryer later to warm up the 'startup cap' to see if this will power it on, rather than having to replace the cap.
If I have to do this everytime I turn wall outlet off, then so be it..

[Davi.p]

Re: Asus VW246H will not power on

"Cap used to replace was recommended by 'selldoor' and is the same rating as the one taken out." Is it a low esr type?
"I will be trying a hairdryer later to warm up the 'startup cap' to see if this will power it on, rather than having to replace the cap." One new cap cannot dry up in less than a month,
if you have used a non low esr the hot air test is a waste of time.
"If I have to do this everytime I turn wall outlet off, then so be it.."
Which life is in that way? Monitors are designed to stay always plugged and last years,
you must repair it and stop.

[UKRobster]

Re: Asus VW246H will not power on

I tried the hairdrier test, but as Davi.p thought, it didn't work.
I thought I would just go ahead and replace the start up cap again.
This hasn't worked either.
It will still not power on

Is there anything else is to try now? Davi.p have you any procedures to offer?

[Davi.p]

Re: Asus VW246H will not power on

It's a thin track to follow but i would check if it arrives voltage at the right pin of the pwm ic, start from the + leg of bigger cap and follow the path, it arrives on 1 or 2 resistors with high value that comes in the chip, that is the leg where you must find an high voltage , maybe around 300v i don't know sorry.. have you ever tested psu output/s in this off state?

[Davi.p]

Re: Asus VW246H will not power on

i see now the photo, the pin is n.8 and the resistor is r605

[selldoor]

Re: Asus VW246H will not power on

I did not actually mean pre heat the start up cap as I knew what you had bought and if you have put it in correctly (asus sometimes silkscreen often is the opposite way to what you expect) it would be fine.

I meant for you to pre heat the other caps as if the startup cap was bad then others may be bad also. It could also reveal a cold joint.

[UKRobster]

Re: Asus VW246H will not power on

I used a hairdryer to warm up the other caps. This made the whole board warm, however it did power on.

I will try replacing the other caps and see if that resolves.
selldoor when you mention a cold joint. Could that be on on of the caps? Or do you mean it could be another component? Is a cold joint on the caps common?
What I'm getting at is that I hope replacing the caps will solve this issue.