Dell 2005 FPW 2 and power flashing

[Nightwolf]

I posted this in an old post and guess no one sees it any more, so posting a new thread.
The monitor when first turned it on, the power lamp and the number 2 flashes on and off. Opened it up and unhooked the four cables going to the inverter, plugged it in and they didn't flash any more and I had all the voltages, 5 on the pins, 12 on the pins and 3.3 on pin 10. Connected the inverter plugs and they flash again. Monitor back light flashes on and off with the 2 lamps.Disconnected the cables again and how the 2 lamps are flashing. Reading across the caps in front of the inverters, I get between 5.7 and 5.8 M.
Any direction from here?

[Agent24]

Re: Dell 2005 FPW 2 and power flashing

Can you post some photos of your boards and show where you are measuring these voltages?

I don't know what you mean by "The number 2 flashes on and off" etc. Please explain or take a video?

[Nightwolf]

Re: Dell 2005 FPW 2 and power flashing

This is where I measured the 3.3 volts.

Both boards.

5 and 12 volt measurement

Flashing number 2 light.
I believe the number 2 is input 2. That and the power light both flash on and off.

[Agent24]

Re: Dell 2005 FPW 2 and power flashing

When the lights are flashing, are the power rails steady or do they fluctuate?

[Nightwolf]

Re: Dell 2005 FPW 2 and power flashing

The 5 and 12 are steady, but the 3.3 fluctuate.

[Agent24]

Re: Dell 2005 FPW 2 and power flashing

How much is it changing by? Does it change in time with the lights flashing?

Could be your 3.3v regulator is bad or there is a short on that rail. Can you locate the 3.3v regulator on the logic board?

[Nightwolf]

Re: Dell 2005 FPW 2 and power flashing

Yes it does with the lights turning on and off. Re-read my first post about the lights.

[Agent24]

Re: Dell 2005 FPW 2 and power flashing

Yes it does with the lights turning on and off. Re-read my first post about the lights.

Yes, but what I mean is, does the 3.3v rail change in voltage in time with the LEDs flashing?

eg: If the LEDs flash once a second, does the 3.3v rail fluctuate once a second too?

And can you measure how much it fluctuates by? Does it drop to 0v and go back to 3.3v again or what?

[budm]

Re: Dell 2005 FPW 2 and power flashing

https://www.badcaps.net/forum/attach...2&d=1426365626
Is the on/off (Backlights ON/OFF command pin) pin fluctuating?

[budm]

Re: Dell 2005 FPW 2 and power flashing

https://www.badcaps.net/forum/attach...0&d=1426365626
"This is where I measured the 3.3 volts."
You are not checking the output of the 3.3V LDO regulator IC?
It looks like there are 3 LDO regulator ICs on the logic board.

[Nightwolf]

Re: Dell 2005 FPW 2 and power flashing

Yes they are in time and from what I can see, the voltage goes up a little over 2 volts buts
it fast and the fluke isn't as fast.

[Nightwolf]

Re: Dell 2005 FPW 2 and power flashing

Yes it goes from the power board to to the logic board. Schematics trouble shooting said that was a good place to check it.

[Nightwolf]

Re: Dell 2005 FPW 2 and power flashing

https://www.badcaps.net/forum/attach...2&d=1426365626
Is the on/off (Backlights ON/OFF command pin) pin fluctuating?

Yes it is also. If the room is dark, you can see the screen flash on and off.

[Nightwolf]

Re: Dell 2005 FPW 2 and power flashing

Readings on 3.3 volt regulators
U 608 output good.
U 610 output good.
U 612 pin 5 on and off 1.5 to 2.9 fluctuating. Input 3.3v-SW
Pin 1 0
Pin2 and 3 1.5 to 2.9 fluctuating
Pin 4 3.3v.
Pin 5 1.5 to 2.9 fluctuating.
Pin 6 3.3v.
Looks like 3.3v-SW goes back to R488 then to U402 pin AF9 GPIO_GO7_B<5>
Don't know what input to the display processor is controlling that output. Can't seem to find and info on the chip GM1501.

[Agent24]

Re: Dell 2005 FPW 2 and power flashing

What is the part number on U612? Can you get a close up photo of it and the immediate area?

[Nightwolf]

Re: Dell 2005 FPW 2 and power flashing

What is the part number on U612? Can you get a close up photo of it and the immediate area?

Here are close ups

[Agent24]

Re: Dell 2005 FPW 2 and power flashing

I don't see a voltage regulator there... Which one is U612?

[Nightwolf]

Re: Dell 2005 FPW 2 and power flashing

I don't see a voltage regulator there... Which one is U612?

U612 is to the right of U609

[Nightwolf]

Re: Dell 2005 FPW 2 and power flashing

Had to send it in to posts from the phone, mail is down on computer

[budm]

Re: Dell 2005 FPW 2 and power flashing

6-pin device U612 si3865, is the on/off pin fluctuating so the output will be fluctuating too.
So need to find out why the control pin is going up and down.
Do you have the link for the diagram or you can just upload it.