HP W2408 Problem

[PlainBill]

Re: HP W2408 Problem

In this case there should not be voltage to the U117 and USBs with the monitor off or in this state, correct?

Correct.

PlainBill

[sprocket]

Re: HP W2408 Problem

OK where we at, are you saying replacing Q110 and U117 will fix it?
If so what did you come up with for a Q110, the one I listed above?

[PlainBill]

Re: HP W2408 Problem

OK where we at, are you saying replacing Q110 and U117 will fix it?
If so what did you come up with for a Q110, the one I listed above?

No, I am saying that it appears that circuit is working as designed. The regulator will be off until a USB device is plugged into the jack.

And I lost track of another detail. I had asked for the part number on U109. What are the voltages on it's pins?

PlainBill

[sprocket]

Re: HP W2408 Problem

pin1 = gnd
pin2 = 3.3 vdc
pin3 = 3.3 vdc

I'm using an analog meter and reading a tad better than 3v and calling it 3.3
I'll dig out the digital and scale down ...
Actually using the digital pin3 is 3.288 and pin2 is 3.294

[PlainBill]

Re: HP W2408 Problem

pin1 = gnd
pin2 = 3.3 vdc
pin3 = 3.3 vdc

I'm using an analog meter and reading a tad better than 3v and calling it 3.3
I'll dig out the digital and scale down ...
Actually using the digital pin3 is 3.288 and pin2 is 3.294

Argh!!! That is PROBABLY a reset controller. They have given us fits on other boards with a Gemini graphics chip. And I just confirmed the gm5868H-LF chip has an internal reset controller.

PlainBill

[sprocket]

Re: HP W2408 Problem

Man you lost me .. where is this gm5868H-LF located and does it say that on it?

OK went back and I see it. That looks like the whole Kaboodle

Changing that would be pretty challenging even if I could get one.

I searched for a new ILIF035 digital board and didn't find any

[PlainBill]

Re: HP W2408 Problem

Man you lost me .. where is this gm5868H-LF located and does it say that on it?

OK went back and I see it. That looks like the whole Kaboodle

Changing that would be pretty challenging even if I could get one.

I searched for a new ILIF035 digital board and didn't find any

Here's the problem I'm having at this point. We have a number of cases where a reset controller was used with a GPU that had it's own reset controller. The usual result was the reset controller failed - shorted internally. Investigating, we saw several points in common - the reset controller showed signs of physical damage, and the GPU was totally dead.

This case is different for several reasons - you haven't reported that U109 has a hole in it, I can't find any information showing that U109 is a reset controller, and most importantly, the GPU IS showing some signs of life.

At this point I'm guessing, but if I had to make a guess, I'd guess that U110 is the problem. That contains the firmware for the monitor, and it may be corrupt. The two paint dots on it suggest it has been loaded with code prior to being installed.

There are a couple of things you can try. With power off, check the resistance between U109 pins 2 and 3. It should read well over 1K ohm, probably over 10K. If it reads less than 10 ohms, remove U109 and try the monitor. Alternatively, with power on, short U109 pin 1 to pin 2 and see if the monitor starts working.

PlainBill

[sprocket]

Re: HP W2408 Problem

U109 2 to 3 measures 4500 ohms

Shorting 1 and 2 and holding it makes the blue light first go out then in about 10 seconds it comes on amber. If I remove the short it goes out and 10 seconds comes back on blue.
If I just hold it shorted, it will be amber and blink off and on every 10 seconds

Yes the back light does come on and a white rectangle like for a message shows in the middle but has no text (just blank white)

I'm going back and try it with a HDMI cable and will report if any difference

OH ya, I do have to ground pin2 to kick start this scenario each time

[sprocket]

Re: HP W2408 Problem

OK here is what happens
With VGA and I reset pin2, the white blank rectangle will show only
With HDMI and I reset, XP desktop actually shows but is really washed out with brightness
In either case above the OSD will not show using any of the keys
If I shut down, the back light will stay lite but I have to reset when I reboot to get XP to show.
I read on the 10 second Menu lockout and none of that worked
Also when changing screens in XP, the brightness flairs all over the place

[sprocket]

Re: HP W2408 Problem

U110 is 25L4025AMC-12G in case this helps

[sprocket]

Re: HP W2408 Problem

Plain Bill
I wish to thank you for all your work for me
It must indeed been the chip lost it's programming. I found a new board for $70 bux and it's now up and running

I got around a $100 in it but I think it's worth more than that

[PlainBill]

Re: HP W2408 Problem

Plain Bill
I wish to thank you for all your work for me
It must indeed been the chip lost it's programming. I found a new board for $70 bux and it's now up and running

I got around a $100 in it but I think it's worth more than that

Glad you have it working. Yes, you made out OK.

PlainBill

[brunolundh]

Re: HP W2408 Problem

Hello!

I found this forum when I was looking for some tips to fix my Hp w2408H monitor that went dead.
Insted of starting a new thread I ask my question in this so I can refer to what already been said.

My monitor:
When it still worked I heard a ticking when I turned my computer off. That was not a problem when i never closed it down.

Then I moved and when i tried to start it again nothing happend. Only the amber status light was on, and i heard the ticking.

Now 9 months later I am looking into it again and found that now the amber status light not light up anymore but i still hear the ticking.

Using either pin 3 or 4 as the ground point, what are the voltages on pins 1, 5, 7, and 8? What is the voltage across C3?

When I try this i get:

C3: varies from about 5V to about 15V
pin 1: varies from about 5V to about 15V
pin 5: varies from about 0V to about 5V
pin 7: 0V
pin 8: 0V

Thanks
Christer Bruno-Lundh

[retiredcaps]

Re: HP W2408 Problem

When I try this i get:

C3: varies from about 5V to about 15V
pin 1: varies from about 5V to about 15V
pin 5: varies from about 0V to about 5V

1) You could have a bad startup cap causing your ticking.
2) You could have dry capacitors causing your voltage fluctuations.
3) There could be a shorted component causing excessive load on the smps.

Either way, post top down view pictures of all your boards following my sig file below exactly.

[brunolundh]

Re: HP W2408 Problem

Here they are:

[PlainBill]

Re: HP W2408 Problem

Here they are:

Great pictures. I have a few questions about what is shown (and not shown) in the picture of the power supply. The cable on CN851 obviously goes to the signal card. Is there a legend (list of functions of the pins) obscured by the cable? If so, I would like a picture of that. Also, a number of components on the heat sink are in shadow. A picture taken from the reverse angle would be helpful in identifying those. Also, a picture of the bottom of the board is necessary, and a picture of the 'daughter board' (connected via CN830) would help identifying it's function.

PlainBill

[brunolundh]

Re: HP W2408 Problem

I can't find any legend. I took a better photo of the connection point.

Tried to take a photo of the "daughter board". I think I have to take it off to take a better picture.

I found something that looks like some burn. (Found it when i uploaded the pictures)
But i can't remember seen it before. Not sure I caused it when I was mesure the the pins yesterday.

[retiredcaps]

Re: HP W2408 Problem

Tried to take a photo of the "daughter board". I think I have to take it off to take a better picture.

No need probably. The important info was clear enough to see.

http://pdf1.alldatasheet.com/datashe.../SG6902SZ.html

I found something that looks like some burn.

That is probably left over flux from the factory. You can clean it with isopropyl alcohol.

[PlainBill]

Re: HP W2408 Problem

Thanks, retiredcaps for providing the link.

brunolundh, refer to the datasheet for the location of pins 10 and 15 on the SG6902SZ. CAREFULLY!!! measure the voltage on from pin 10 (black lead) and 15 (red lead) on the IC. It's tight quarters, we may have to find another way to do this.

PlainBill

[brunolundh]

Re: HP W2408 Problem

There was no problem, I had a little help reading the voltmeter.

The voltage varies on that pin. From about 10-15V pretty fast.

/Christer