Asus VW246H will not power on

[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

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

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.

[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)

[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

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

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

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

Hey everyone, Same monitor and same issue.
I've been following the troubleshooting suggestions above and here's my finding.
The problem it appears to be in fuse FD851... I'm getting a reading of 126ohm.

Also while plugged in, the Big brown cap reads 160V (I'm in the US).

Any ideas? does the fuse need replacement, or do I need to do further tests?>

[Davi.p]

Re: Asus VW246H will not power on

I don't understand ukrobster, you have assembled back together and it not working (sorry for my english), then you have done several test where all the times you switchoff the monitor and unplug the power from the wall? But the real test was also to switch on and off without unplug it..

[Lumberjack777]

Re: Asus VW246H will not power on

Great to hear! Thanks for the feedback. I love it when it's just that little cap

And thanks to Selldoor for the place to buy the right cap in the UK

[UKRobster]

Re: Asus VW246H will not power on

Hi guys,
Sorry for not posting back sooner, but I am in the middle of decorating and that took all of my time over the weekend!

Anyway I have some good news.
I replaced the start-up cap last night and tested the monitor.
It powered on! Great!

Then (not so great) I started putting it all back together, just finished clipping the case together again, and thought I would just test it again before assembling the stand.
It would not power on! It was late, and I although I was tempted to tinker some more I went to bed.
Today I started thinking that I could be having the same issue as before:
As in, after switching off the wall outlet I would have to leave it unplugged overnight for it to power on again. So this evening I have tested it again & it powered on first time. So I switched off the wall outlet and unplugged the power cord. Plugged it all back in and tried again. It works!
I have performed this procedure several times and it seems to power on every time (so far!)

A massive Thank You! to Lumberjack777 & selldoor for your help.
I cannot express how grateful I am, that fixing my screen so close to xmas only cost me 89p!

I do however have my fingers crossed that the wall socket/leave overnight scenario doesn't occur again.
But if it does you know the first place I will be posting

Thanks again,
Rob

[Lumberjack777]

Re: Asus VW246H will not power on

Oh OK, I didn't realize the boards needed connecting while testing - D'oh!
I will see if I can get it hooked up and read them again, properly!
Thanks for the tip about the sewing needle!

If I did use a hairdryer on the start-up cap and it powered on. What would that prove?
Does that indicate the cap is at fault?

Yeah, the probes on my DMM are so thick I soldered needles to them. It really helps if you are checking little legs from an IC chip.

But you should have at least had standby voltage of 5V from one of the wires to the main board. Even if everything wasn't connected. But connect them all and see if you have a difference eh.

The hairdryer is a great tip. As an aluminum capacitor heats up the ESR gets lower and lower (good). That's why people can turn off a perfectly good monitor. But it won't start up the next time. BUT....if the little capacitor is completely dried up on the inside, it won't make any difference. Worth a shot though.

[UKRobster]

Re: Asus VW246H will not power on

Oh OK, I didn't realize the boards needed connecting while testing - D'oh!
I will see if I can get it hooked up and read them again, properly!
Thanks for the tip about the sewing needle!

If I did use a hairdryer on the start-up cap and it powered on. What would that prove?
Does that indicate the cap is at fault?

[selldoor]

Re: Asus VW246H will not power on

OK - Not sure about the connector test.
When doing this you usually need to have all the boards connected. It doesnt make it easy as you have to try to get the probes to the pins with the socket in place and if you dont have thin probes its a problem. Some people have had success by inserting a sewing needle into each hole on the socket one at a time then putting the probe to the needle.
It has to be connected up as when you switch on there are signals go back and forth between the boards and it does a self test before it starts the power supply fully.

Something else to try whilst waiting for your cap is to set it all up, and if you have not yet removed the start up cap, warm it gently with a hairdryer then
try and power up the monitor.

[UKRobster]

Re: Asus VW246H will not power on

I checked the fuse at F851 and it eventually settled at 0.6 - as before.
Then checked each connection in the connector CN701, with the mains plugged in.
Nothing - well not actually true I got -0.03 on most of them. Certainly no volts through!
So I didn't bother to take a picture at this point as it seems the power is not getting that far.

selldoor: thanks for the link for the start-up cap. I had been looking this afternoon and had seen a couple of another site http://uk.rs-online.com/web/ but they had different ripple current ratings.
The one you have recommended has yet another different rating! Geez there is a lot to learn about all this stuff!

I have ordered the cap you pointed out, will change it and let you know the outcome!

[selldoor]

Re: Asus VW246H will not power on

I have looked but dont have a new cap to send.

Suggest this one http://cpc.farnell.com/rubycon/50yxf...nce/dp/CA05111

They seem to have a no postage offer on at the moment even for small orders.

They are in packs of 5 so you order 1 - should be 89p inc vat

If you struggle to get the no handling and no postage let me know.

[UKRobster]

Re: Asus VW246H will not power on

Ok Robster. Let me translate; since I remember what it was like to be a novice.

Thanks for your patience, it is appreciated.

I will check those things and let you know.

Thanks guys!

[Lumberjack777]

Re: Asus VW246H will not power on

Ok Robster. Let me translate; since I remember what it was like to be a novice.

Selldoor - is asking you to check the fuse F851 just like you checked the white one earlier. Should show very low ohms if its good.

Newtothis - is asking you to see if you have any voltages going to the main board. The connector is CN701 and it's the white plastic thingy with the wires coming out. Set to 20 volts dc and put the red probe into the holes where the wires are. The black probe goes to a screw on the main board (cold ground). You should see voltages like 5v, 12v. Any voltage at all. I doubt you will, because I don't believe your power transformer is starting up at all.
You can disregard the comment about the ccfl's because they won't cause a no power/led problem.

Also you UK guys. He needs to be able to get a low esr 47uF 50v capacitor in the UK. Just in case it does turn out to be that little startup capacitor.

[selldoor]

Re: Asus VW246H will not power on

Hi - Iam just on my way out but another quick test would be on the yellow/orange torpedo fuse at the top of your first picture designator is F851.
NO power to boards meter on ohms 200 should read the same as holding the probes together.