2 dead monitors, blueh h94w and amw x1700ds

[flosers]

Re: 2 dead monitors, blueh h94w and amw x1700ds

S1 to S2 is for the first and S3 to S4 for the second transformer.You can see that on this picture:
http://hpics.li/245a564

[budm]

Re: 2 dead monitors, blueh h94w and amw x1700ds

OK, I see now per selldoor picture.

[selldoor]

Re: 2 dead monitors, blueh h94w and amw x1700ds

OK if you are happy the bulbs work and the transformers seem ok then
next thing to test is the Mosfets. On the bottom of the board 2 black square
components with 3 legs. can you read the part numbers on them?
In the guide you have mentioned start at post 19 and see the section on mosfets and do the test.
NO power to the board
If you dont understand or get stuck, just ask.

We prefer to have pictures hosted on site so they are there for others to refer to in future- I have added yours to this post.

[flosers]

Re: 2 dead monitors, blueh h94w and amw x1700ds

I have set my multimeter on 2M otherwise I can't see value because they are to high.
The 1st Mosfets
Legs * to *
1 - 2 0,770
1 - 3 0,764
2 - 3 0.004
The 2nd Mosfets
Legs * to *
1 - 2 0,749
1 - 3 0,747
2 - 3 0,006

Mosfets seem to be good?
Thank's for your help

Edit:
the number on the Mosfets is: 9977GH
803516
Note: the second legs are not connected to the board but it seems normal

[selldoor]

Re: 2 dead monitors, blueh h94w and amw x1700ds

Yes - they look ok as well - going back to the transformers can you test the resistance
on the primary side (6 pins) meter on ohms 200 test pin1 to 3 then 3 to 6 then 1 to 6
on each it will be quite low.

[flosers]

Re: 2 dead monitors, blueh h94w and amw x1700ds

Fist transformer
1 to 3 = 0.5
3 to 6 = 0.3
1 to 6= 0.5
Second transformer
1 to 3 = 0.3
3 to 6 = 0.3
1 to 6= 0.4

[selldoor]

Re: 2 dead monitors, blueh h94w and amw x1700ds

I believe they are ok - at least not open or widely different.
It will be tomorrow but I will try and decide what to test next.
Didnt quite understand your bulb testing may have to look at that again
though it seemed thorough.
Perhaps need to look at the signals from the main board there may be a pin on the connector called BLON InvON or maybe just ON and we need to see what that is doing when the lamps flick on and off.

Oh!! I dont know if we have asked if you have a known source connected
and if so when the backlight has gone off can you see a very dark image on the screen
Sometimes helps to shine a flashlight at an angle onto the screen.
Bon Nuit

[flosers]

Re: 2 dead monitors, blueh h94w and amw x1700ds

Ok thank's for your help
Bonne nuit a vous aussi

[Rtech]

Re: 2 dead monitors, blueh h94w and amw x1700ds

There is no mention of checking voltages to the inverter.I assume the 4A fuse has been checked,and the diodes D805-1,D805-2 and the 2 similar ones above them,do need testing.I find Diodes like this, in this part of the circuit,which in a lot of cases have standard Schottky Diodes mounted on heatsinks,fail regularly in many Power Supplies not just Tv and Monitors.

[flosers]

Re: 2 dead monitors, blueh h94w and amw x1700ds

I have done some test again and today my screen haven't back light for few minute before shutdown, the led still green except when they are no source.I'm not sure to see something with flashlight but with an external inverter It's work.Notice that I can't connect the fourth CCFL to my external inverter I have just one output.
For the other test more information will be welcome

Rtech I need to check diode in the inverter part?
Edit:
I have checked diodes and I have ohm result on both sides for 4 diodes D805-1,D805-2,D807-1,D807-2.That's very strange?
The 4A fuse is ok.

[selldoor]

Re: 2 dead monitors, blueh h94w and amw x1700ds

"today my screen haven't back light for few minute before shutdown," Not sure what that means. For may tests you need a 3v battery of some sort either a CR2032 or 2AA or 2AAA
batteries OR a 500-1000ohm resistor

So with it connected to a PC and using an external inverter to power the bulbs, the bulbs stay on and you see images on the screen?

@Rtech good morning- perhaps you can help him with the diodes I didnt bother about the 4a fuse as the lamps flash on - I dont think they will if the fuse is bad? Also
I dont think you can test the voltage into the inverter without an oscilloscope.

[flosers]

Re: 2 dead monitors, blueh h94w and amw x1700ds

At the beginning the monitor stay on few minute then I have a black screen.Now I have a black screen directly except with an external inverter.
Yes the monitor work,I see an image on the screens even though I have just one CCFl connected to the inverter.

[flosers]

Re: 2 dead monitors, blueh h94w and amw x1700ds

What I need to do with my 3v battery?

[selldoor]

Re: 2 dead monitors, blueh h94w and amw x1700ds

Ok - and you say you have tried each bulb on the external inverter?

Oh! if you now only have a black screen all the time better check that fuse its a small
yellow torpedo one - we can just see it in one of the pictures.
Power off
Meter on ohms 200 place one probe on each end of fuse should be same result as touching the probes together.
If that is ok - next test

You need to connect everything up as it was then remove the lvds cable from the main?logic board. Switch on and report what happens. Obviuolsy there will not be a picture but sometimes the back lights stay lit.

Switch off

Next plug the lvds back in and unplug the cable form the power supply to the Main?logic board.
On the power supply the socket to the main board has a pin labelled on/off

You need to connect a 3v battery neg to the 5v pin and the positive to the on/off pin
then power up the board - with a lot of luck the light may come on?

EDIT: See post #58 below, the above was a mistake!

[flosers]

Re: 2 dead monitors, blueh h94w and amw x1700ds

Yes I have.
You talk about the 4A fuse that Rtech ask me to check?
Like I said he is good.
1.The light stay 2 seconds and the screen come black again,I conected a source but still nothing.
2.Ok I understand,I eat and I do that after

[flosers]

Re: 2 dead monitors, blueh h94w and amw x1700ds

I just finish and the monitor don't work the led is not Switched on.The sceen is black.I heard just a regular sound.
Tank's again for your help
Edit:
I have connected my 3v battery on the board with a vga input not the PSU board,that's correct?

[selldoor]

Re: 2 dead monitors, blueh h94w and amw x1700ds

Not even a flash
Ok - Put it all back together and set your meter on 20vdc and switch the set on.
First put the black on a ground screw and with the red probe test the voltage at each side of the 4A yellow fuse.

Next switch it off (You may need help with this) you have to put black probe to ground
screw and with the red probe test on the on/off pin WHILE you turn the monitor on
and for about 10 seconds after or until the light flash on then off again.

[selldoor]

Re: 2 dead monitors, blueh h94w and amw x1700ds

BLAST!! Back to the battery test post 54 (hope I havent damaged anything !!!)
It should have been battery from Gnd to on/off The 5v to on/off is for the resistor

[flosers]

Re: 2 dead monitors, blueh h94w and amw x1700ds

Nothing,I have connected my battery to the vga board , not PSU board that's correct?

[selldoor]

Re: 2 dead monitors, blueh h94w and amw x1700ds

No! we are both getting it wrong

What we are doing is to try and jump start the power supply
to work the inverter section.

On this monitor the inverter section is on the same board as the power supply so it makes it a little difficult to follow.

Anyway it is the Power supply board we are working on - the main board is
unplugged and we replace the on signal that normally comes from the main board
with the 3v from the battery so it is the pins on the socket on theleft side of board in this picture
https://www.badcaps.net/forum/attach...2&d=1405538933