Asus VE205 .... 2seconds to black

[Welchs101]

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

There are two alpha omega 4614 chips..........they both measure the same

S1-G1: PINS 3,4: 5.1Kohm
S1-D1: PINS 3,6: 1meg to 3megohm
G1-D1: PINS 4,6: 1meg to 3meg ohm
S2-G2: PINS 3,4: 10.1Kohm
S2-D2: PINS 3,6: 2meg to 3megohm
G2-D2: PINS 4,6: 2meg to 3meg ohm


so i guess these are ok........

any ideas on other things to check?

[retiredcaps]

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

How to make measurments to verify this is a good part? Any ideas?

For mosfets, I check for shorts between source-gate, source-drain, drain-gate. The AO4614A has two of each.

So test S1-G1, S1-D1, G1-D1, S2-G2, S2-D2, G2-D2. Any reading under 30 ohms suggests a short. I normally test "in circuit" and if I get a reading under 30 ohms, then I desolder and retest.

Others test mosfets like this ...

http://www.4qdtec.com/mostest.html

[Welchs101]

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

Just curious about the IC Alpha-Omega 4614......

IC: alphaomega 4614
https://cdn.badcaps-static.com/pdfs/...0e94bf963c.pdf

How to make measurments to verify this is a good part? Any ideas?

[Welchs101]

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

alexanna, i really appreciate your help......thanks.

lets see if anyone else on here has any ideas. if not, no worries, as i said i was trying to do my neighbor a favor by fixing but with all the "black friday" deals going on they should be able to get a new monitor cheap......not as cheap as "0" but still cheap.............

[alexanna]

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

When monitors first turn on they go through a self test of the inverter. By turning the back lights on to full brightness to check for proper voltage and current flow. So the back light on voltage starting high and going low and then going back high in my opinion is OK.
As long as pin 11 VDDA stays the same when the backlights are on and off, that also should not be a problem.
Even if a schematic was available this would be a difficult one to diagnose.
At this point I am out of ideas.

[Welchs101]

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

pin 11 with computer connected relative to pin5 (gnd) is 5.0V.

[alexanna]

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

Good,now would you measure pin 11 VDDA.
With a signal applied to the monitor.

[Welchs101]

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

with computer connected............

P16 initially is at 2.9Volts........

then fluctuates to around 0.1V

then fluctuates back to 2.9V and just stays there

LED light stays blue entire time during measurement

[Welchs101]

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

hummmm......good question. I did not connect the computer....let me do that and repeat the measurements. sorry about that.

[alexanna]

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

ok, reconnected computer to monitor
powered on computer
powered on monitor

LED light comes on as blue and stays blue..........screen will flash with computer desktop but then goes blank...........even after monitor goes blank LED light is blue.........

Do you still have a siginal going to the monitor when you are checking voltage to the controller?

[Welchs101]

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

Sorry, measured the wrong thing.

Using pin 16 (ENA pin) and pin 5 (as gnd).

Power on the monitor and LED light turns blue...........
Pin16 DC voltage relative to pin 5 is........2.9Volts

when LED light goes orange the Pin16 value drops to 0.1Volts

Is this what you wanted measured? If not just let me know.

[alexanna]

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

You measured the power supply voltage to the controller; Let me get back to that in a moment.
Measure the enable or back light on voltage positive lead on pin 16 lead,what voltage reading do you get with the back lights on and 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.

[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.

[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

[Welchs101]

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

to test the BLON voltage i just monitor pin 16?

[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

i think the part number is

"OZ9933GN"

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

[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.

[alexanna]

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

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