LCD monitor VT17W7X not powering on

[Welchs101]

Re: LCD monitor VT17W7X not powering on

I measured the voltages (again with lcd panel disconnected.....its just easier to do) of the following regulators (see pic for detail locations):

1) Markings: AIC1084
Pin1: Measured 2.07V DC
Pin2: Measured 3.32V DC
Pin3: Measured 5.06V DC


2) Markings: BS17P, Z74C4 (could not find datasheet on this one):
Pin1: Measured 0.606V DC
Pin2: Measured 1.87V DC
Pin3: Measured 5.06V DC

[Scenic]

Re: LCD monitor VT17W7X not powering on

hook up a computer displaying something and see what it does.
i had a couple of noname LCDs which never turned on when AC power was applied. (no "no-signal" message.. they just went straight into standby and stayed like that).
those needed a signal to turn on.

also, if i were you, i would have replaced all the g-luxons by now.
they usually just dry up without showing any obvious signs of failure..
(and caused tons of really odd quirks on old gigabyte mainboards that way)

[Welchs101]

Re: LCD monitor VT17W7X not powering on

Forgot to submitt picture

[Welchs101]

Re: LCD monitor VT17W7X not powering on

hi abit,

ok...i will hook everything up and give it a try. I have not replaced all the caps but i did replace most of them. If you think this will help i can replace them but i would rather not put parts in unless i think it will help.

thanks.

[alexanna]

Re: LCD monitor VT17W7X not powering on

yeah, i tried the button with everything hooked up except a computer. Do you think i need to hook up a computer to the monitor before the LED will come on?

How did you know the backlights off voltage was ok?

I will check the voltage regulators and let you know what i find.

On a computer monitor, when the logic board requests the back lights to be on it will supply the B.L.or the On off pin a voltage. Usually this will be around 3.2 volts D.C, I have seen some be a higher voltage.
If you have a working monitor you will see this voltage go from a high voltage to close to 0 volts as the power button is pushed.

[Welchs101]

Re: LCD monitor VT17W7X not powering on

hi alexanna,

which pin is this on my monitor......is it the ONB pin?

[alexanna]

Re: LCD monitor VT17W7X not powering on

hi alexanna,

which pin is this on my monitor......is it the ONB pin?

I don't have the monitor in front of me at the moment, But the on b is probably the on off signal.
You have a monitor that will not turn on so it makes sense to see a low voltage on that pin.
You need to concentrate on why the monitor will not turn on. Did you ever hook up a video source?

[Welchs101]

Re: LCD monitor VT17W7X not powering on

just put everything back together and well it still does not power on. It was worth a shot but no luck.

Any other suggestions?

[alexanna]

Re: LCD monitor VT17W7X not powering on

just put everything back together and well it still does not power on. It was worth a shot but no luck.

Any other suggestions?

Shot in the dark, Try unplugging the LCD panel and all of the back lights. See if the PLED will respond to power on and off.
I can't get to my monitor just yet it's in my pick up, We have had a lot of snow and ice and really cold temps.I said screw it to having some shovel my driveway the last time it snowed. At the moment I've got 2” of solid ice and no ice skates.

[Welchs101]

Re: LCD monitor VT17W7X not powering on

i will try removing the backlight connections and then let you know what i find out. cant do it righ this min but i will get to it this afternoon.

[Welchs101]

Re: LCD monitor VT17W7X not powering on

ok, i tried it. I unplugged the lcd panel and the bulb connections. Power up and connected it to a computer video source..........still nothing?

Any ideas?

[Welchs101]

Re: LCD monitor VT17W7X not powering on

Dont know if this helps or not but here is some additional info.

With the lcd panel removed/unplugged and no bulbs connected ......i power up the psu and logic board (which was connected to a computer). I monitored the voltage on the ONB pin as i toggled the on/off switch. No change in the voltage at all.

Does this help?

[alexanna]

Re: LCD monitor VT17W7X not powering on

ok, i tried it. I unplugged the lcd panel and the bulb connections. Power up and connected it to a computer video source..........still nothing?

Any ideas?

I am going to test my skating abilities here real soon.
You could check voltages at the front panel switch. I would expect to see one toggle between a high and low voltage as the power button is pushed.
I don't know which pin or the voltage you will see. I will try to get the monitor in the house latter in the afternoon.

[Welchs101]

Re: LCD monitor VT17W7X not powering on

If your like me .......i cant skate.......so better to wait.

I will check voltages........

[alexanna]

Re: LCD monitor VT17W7X not powering on

The larger of the 2 regulators is 3.3v, the smaller one is 2.5 v.
On the ten pin connector starting at the top 12v pin
Pin 6 is the adjust or dim pin it reads .33v with back lights on
Pin 9 ONB or back light on off reads 5.1 volts with the back lights on.

On the front panel switch from left to right
Pin 4 through 9 = 5.5v
Pin 11 =2.1v with the PLED lit and 0v when off.
Pin 11 changes from low to high as the power button is pushed.
I was probing around to try to trace the 2.1 v signal, this is just a guess but there is a chip on the logic board “Sync Moss” but it probably originates from there because of some shaky hands I thing I shorted something out on because the 2.1v is no longer at the front panel switch and the monitor will no longer turn on.
I really suspect if you don't see 2.1v at the front panel switch you're probably looking at a logic board replacement.

[alexanna]

Re: LCD monitor VT17W7X not powering on

I just reread everything; it looks like The BS17p regulator may be bad. I measured 2.5 volts on my regulator.

[Welchs101]

Re: LCD monitor VT17W7X not powering on

alexanna,

I was just typing the same thing. Do you have a datasheet on this? I cant find one.

Also, i am really sorry you shorted something. I kinda feel bad. Now you have a broken monitor. I hope it was not one you used often.

I have some other questions on what you typed but i wanted to think about what you typed a little more.

Also, if you or anyone else can find a data sheet on this regulator i would appreciate it.

thanks again for your help!

[alexanna]

Re: LCD monitor VT17W7X not powering on

alexanna,

I was just typing the same thing. Do you have a datasheet on this? I cant find one.

Also, i am really sorry you shorted something. I kinda feel bad. Now you have a broken monitor. I hope it was not one you used often.

I have some other questions on what you typed but i wanted to think about what you typed a little more.

Also, if you or anyone else can find a data sheet on this regulator i would appreciate it.

thanks again for your help!

I probably was not going to fix this one anyway, I need the stand for a 19” I just repaired and the LCD is going into a Dell with a broken screen.
I do not have a data sheet on the regulator.
Some regulators use a resistor to adjust their output; hopefully someone else can answer that question for you

[Welchs101]

Re: LCD monitor VT17W7X not powering on

I still feel kind bad. Thanks for all your help thus far.

I did have another question regarding the push buttons.........i am having the hardest time figuring them out.

I have taken a picture both front and back of the power button which is right next to the LED.

Can someone explain how this works?

[alexanna]

Re: LCD monitor VT17W7X not powering on

On the picture I provided, I called pin #1 the one furthest away from the LED