Asus VE205 .... 2seconds to black

[KalvinAlmeda]

Re: Asus VE205 .... 2seconds to black

For what I have been reading and my experience ( EE in college ), is that perhaps the CCFL is bad. However, I began to notice the corner becoming slightly discolored and some slight flickering in contrast ( no color ) before this issue happened. Perhaps that could aid you in our diagnostic quest. I am going to try and replace the slow burn fuse tomorrow and I'll let you know what I come up with.

[Welchs101]

Re: Asus VE205 .... 2seconds to black

hi kalvin,

i tested the ccfl's (ie...the bulbs) and they appear fine. I used another monitor to power the bulbs from the ASUS and they came on fine.

[KalvinAlmeda]

Re: Asus VE205 .... 2seconds to black

I am going to buy some 30 AWG to replace the fuse ( as a test ).

[Welchs101]

Re: Asus VE205 .... 2seconds to black

just curious what part your referring to.....can you take a pic of the part your testing?

[KalvinAlmeda]

Re: Asus VE205 .... 2seconds to black

The white pigtail tube fuse. Its pretty clear as day to see it on the board. You have to de-solder it from the board.

http://www.goldmine-elec-products.co...es/G16104B.jpg

[Welchs101]

Re: Asus VE205 .... 2seconds to black

did you test the fuse to see if it was an open?

[KalvinAlmeda]

Re: Asus VE205 .... 2seconds to black

Well, I scratched off the paint ( I believe its paint ), and the inside was completely black inside, typically indicative of a burnt fuse. I don't have a multimeter to test the fuse with, and forgot to pick up 30 AWG copper wire from work today. Looking for an old power supply to break open around the house to use. Anybody with a fix will earn 20 USD through paypal.

[Welchs101]

Re: Asus VE205 .... 2seconds to black

ok. I replaced caps but still the monitor does not come on.

I replaced caps (see enclosed file)
1:330uF/35V
2:330uF/35V
3:680uF/16V
4:680uF/16V
5:470uF/16V
6:470uF/16V

I DID NOT replace caps 7 and 8.

Cap 7 is 47uF / 50V
Cap 8 is the "big" cap which i understand does not normally go bad.



i recall from a post bill put out some time ago. I have done all of these. But i have not gotten any feedback on #2. Does anyone have any other ideas on this monitor. If not i am going to give it back to my neighbors and tell them to buy a new one.


2 seconds to black......things to initially try (from bill post)
1. Replace any suspect caps (Elite, Suscon, Capxonand other caps on the bad caps list are automatically suspect).

2. Compare the resistance of the transformer secondaries. If they don't match to within 3% replace the one with the lower resistance.

3. Substitute known good CCFLs

[Welchs101]

Re: Asus VE205 .... 2seconds to black

One other comment. If you power the monitor up and connect a computer to it the screen goes blank as i said before. However, you can see the faint image on the screen if you shine a flash light at the monitor of whats supposed to be on the screen.......hope that made sense. Basically, the video signal is getting tot he monitor but its just not staying on to display it.

[alexanna]

Re: Asus VE205 .... 2seconds to black

You haven’t substituted known good CCFLs yet, you have tried the CCFLS in a different monitor.
If the secondaries are only using one coil there is nothing to compare the resistance to
Try flowing new solder in the areas around the inverter transformer.
Is the back light on voltage reaching the inverter controller?and stay the same when the backlights go off?

[Welchs101]

Re: Asus VE205 .... 2seconds to black

update: I took two known good ccfl's from the test monitor and plugged them into the ASUS (not working monitor). I connected the computer and power to the ASUS. Turned it on and .........nothing. CCFL's come on but then go out. Same situation as when i had the CCFL's from the ASUS connected.

I also reflowed the solder on all the transformer connections...........no change after this either.

thanks for the ideas. If you have any others i will try them........provided i can do them.

[Welchs101]

Re: Asus VE205 .... 2seconds to black

where would i measure the back-light on voltage?

[alexanna]

Re: Asus VE205 .... 2seconds to black

What is the number stamped on the IC circled in brown?

[Welchs101]

Re: Asus VE205 .... 2seconds to black

i am enclosing a pic of the part........

the marking on the part looks to be the following:

0Z9933GN
A98TP4 20
0946A

The "6" in the last line could be either a 5 or 6 but i think looking at it with a magnifying glass looks like a 6.

[Welchs101]

Re: Asus VE205 .... 2seconds to black

i think the part number is

"OZ9933GN"

first letter is an "oh" not "zero".........i think

[alexanna]

Re: Asus VE205 .... 2seconds to black

I am going to be out for awhile,
Here is the only information I found on the OZ9933
Looks like pin 16 is the BL on pin

[Welchs101]

Re: Asus VE205 .... 2seconds to black

to test the BLON voltage i just monitor pin 16?

[PlainBill]

Re: Asus VE205 .... 2seconds to black

to test the BLON voltage i just monitor pin 16?

Yes. Note that it is labeled ENA - Enable.

PlainBill

[alexanna]

Re: Asus VE205 .... 2seconds to black

Yes positive lead to pin 16 for the BL on signal, It will probably read about 1 volt.
You just need to compare the voltages when the backlights are on, and see if it stays the same when they shut off.
Pin #4 looks to be the ground. And pin #11 VDDA is the power supply to the controller.
I do not know the exact voltages you will see, you are just looking for something different when the lamps are on and when they shut off.

[Welchs101]

Re: Asus VE205 .... 2seconds to black

ok, sorry for not responding sooner..........just recovering from the flu.

Ok. I finally made the measurement.

Postive lead on pin 11 and gnd lead on pin 4 as you recommended.

I powered lcd monitor on and immediately saw 5V.......LED light is blue.........once LED light switches to orange........voltage reading drops from 5V to 3.7V and then goes back to 5V.