HP w2007 white screen problem

[pcjiet]

Hello, nice o meet you all...

I have a HP W2007 LCD 20" monitor. Some day i was playing a game and my screen turn all in full white screen.

I was searching for a solution but no luck.
I opened the monitor and check capacitors and seems to be all ok.
I check the voltage in the power board (E131175) in P802 cable, the board says 5.1 V in 4 points but my multimeter says there is 5.9v in each of the 4 points. the Is this ok?

please help me!

sorry for my english :P

[retiredcaps]

Re: HP w2007 white screen problem

I check the voltage in the power board (E131175) in P802 cable, the board says 5.1 V in 4 points but my multimeter says there is 5.9v in each of the 4 points. the Is this ok?

A few people in the last week have been using multimeters with low or near dead batteries. This gives poor and inaccurate readings.

As a test, put your multimeter on the lowest ohms setting (probably 200). Touch the red and black probe together. You should get something less than 1.0 ohms. If not, check/change your battery and/or reseat/clean your probes.

If you do get less than 1.0 ohms, then 5.9V DC is too much for a connector marked 5.1V DC.

To help us help you, post clear focused pictures after reading

https://www.badcaps.net/forum/showthread.php?t=1868

Please do not post pictures inline as they slow down the loading of pages.

For best picture quality and clarity take your boards to a window on a sunny day, turn flash off, and use macro mode. Take a top down view of all your boards (front and back). Make sure the photo is legible so that we can read the PCB printing clearly. A shutter speed of 1/125 or faster will produce nice clear focused pictures. Try to get a photo that is 2000x2000 resolution or as close as possible.

Here is an example of the pictures we want.

https://www.badcaps.net/forum/showpo...94&postcount=1

Once the pictures are loaded, we can suggest test points.

[pcjiet]

Re: HP w2007 white screen problem

This are the pics, do you think its the power board? or mabe the logic board?

[retiredcaps]

Re: HP w2007 white screen problem

This are the pics, do you think its the power board? or mabe the logic board?

AARRGHHH. Please do not post pictures inline as they slow down the loading of pages. Please use the edit button to fix this.

Please post pictures of the logic board, but NOT inline. Also the logic board connects to the lcd panel. On this panel, there will be a pcb. Please also post those pics.

[pcjiet]

Re: HP w2007 white screen problem

here are the logic card and the pcb... in the board atached to de LCD screen, i check in diode mode the F5, i think is a fuse and there is infinite resistence, mabe is the bad one. But what about the 6v in the marked 5.1v spots?

[retiredcaps]

Re: HP w2007 white screen problem

i check in diode mode the F5, i think is a fuse and there is infinite resistence, mabe is the bad one. But what about the 6v in the marked 5.1v spots?

F5 is a fuse. I usually use the ohms test instead of diode. In ohms, a good fuse should measure less than 1.0 ohms.

Regarding the 6V, please refer re-read the first 3 sentences back in post #2 and post the results.

[pcjiet]

Re: HP w2007 white screen problem

hi thanks for answering ^^, i done the multimeter check in post #2 and it marks 0.5 ohms, then the multimeter is ok right? I think the F5 is open, mabe because those 6v, what should i do next? btw i have a digital and an analogic multimeters.

[retiredcaps]

Re: HP w2007 white screen problem

i done the multimeter check in post #2 and it marks 0.5 ohms, then the multimeter is ok right? I think the F5 is open, mabe because those 6v,

1) Okay, if touching your probes together gives 0.5 ohms, then your multimeter is working fine.

2) Let's measure F5 with the ohms. Set it to 200 ohms (if manual). What ohms reading do you get on F5 fuse?

3) 6v could be the voltage for an unregulated load. Once load is applied it could drop to 5V. So hookup all your boards and put in the ground screws.

4) Near the top of your photo, there are two schottky diodes mounted on the heatsinks. Use a ground screw for your black probe. With the lcd plugged into a power outlet, measure the middle pin with your red probe on both diodes for DC voltage.

5) Report each voltage.

[pcjiet]

Re: HP w2007 white screen problem

- the F5 dont mark a thing, the 2 multimeters dond mark nothing.

- the left diode from the photo marks 26.9v to 27.2v and the right diode near the output cables marks 6.2v

[retiredcaps]

Re: HP w2007 white screen problem

- the F5 dont mark a thing, the 2 multimeters dond mark nothing.

- the left diode from the photo marks 26.9v to 27.2v and the right diode near the output cables marks 6.2v

What do you mean by nothing? Please report the actual reading. If it is "1" on the left hand side of the multimeter, please say "1". If it says 0.1 ohms, please say 0.1 ohms. Nothing doesn't tell us anything.

[pcjiet]

Re: HP w2007 white screen problem

1 on the left hand side

[retiredcaps]

Re: HP w2007 white screen problem

1 on the left hand side

"1" on the left hand side means out of range or infinite. This verifies that your fuse is bad.

As for the other voltages especially the 6V, the caps on that 5.1V rail could be bad? You could try replacing all the caps on 5.1V rail. The caps will be probably 1000uF 10V.

[pcjiet]

Re: HP w2007 white screen problem

i will replace the caps, but how can i get another of those tiny fuses, whats the value or the amperage?

[retiredcaps]

Re: HP w2007 white screen problem

i will replace the caps, but how can i get another of those tiny fuses, whats the value or the amperage?

Post a clear focused close up picture of the fuse and maybe someone will be able to decipher the markings? Are there any markings on it?

[pcjiet]

Re: HP w2007 white screen problem

this is the pic of the fuse (F5) there are no marks on it, its just blue, in the pic you can see the little cable burned or opened inside the fuse.

[momaka]

Re: HP w2007 white screen problem

but how can i get another of those tiny fuses, whats the value or the amperage?

My guess would be under 2 Amps based on what I've seen in other monitors. Not sure about exact rating, though. You can buy those fuses at Mouser or Digikey. Probably best to buy a few dozen with different ratings in the range of 1 to 2.5A.

Before you replace the fuse, however, there are a few other things you should check on the panel board.
1) Measure resistance between ground and the inductor L2 ("3R3") (circled in red)
2) Measure resistance between ground and cathode side of D10 (circled in yellow).
3) Check D10 with diode test on your multimeter.
4) Measure resistance between ground and the tab of U1 (circled in blue).
Post back what results you get for above measurements.
Also, what are the marking of chip U11?

[pcjiet]

Re: HP w2007 white screen problem

the values are:
1) L2: the multimeter in range of 20k ohms marks 5.23, 5.22, 5.21, 5.20, 5.21...
in range of 200 ohms marks 1820, 1821, 1822, 1823, 1824...
2) D10 catode: multimeter in range of 200 ohms marks 21, in range of 20k marks 0.00
3) D10 check: my multimeter dont have a beep, so i will put here the marks: in "diode test" range marks 267 inverting the proves marks 1036. With ohms set in range 20k marks 5.45 and inverting the probes marks 1 in the left of hand
4) u1 check: in range of 20k ohms marks: .45

- u11 chip: AAT1164C, AC2082, 0650

[momaka]

Re: HP w2007 white screen problem

2) D10 catode: multimeter in range of 200 ohms marks 21, in range of 20k marks 0.00

21 Ohms seems low. Looks like something could be shorted on the main boosted voltage rail, then. I just repaired a monitor like that 2 weeks ago (Samsung SyncMaster 931B). Problem was a shorted ceramic cap (it was showing ~30 ohms - ceramic caps should appear as open circuit when measured on a multimeter).

U11 is the chip that provides all of the necessary voltages on the panel board. It is AAT1164C as you stated - Google the datasheet and download it, it will be very useful.

On your monitor, the main boosted voltage rail (given as Vout1 on page 14 of the datashet) is basically everything that is directly connected to the cathode of D10 (circled in yellow in picture in previous post). With that said, we (i.e. you ) have to find which component is causing the above low reading of 21 Ohms (for our purposes, I'm just going to call this reading a "short circuit" from now on).

Now, If you could post a larger version of the picture just like the one I edited, that would really facilitate things. From what I can see, the main boosted voltage rail continues through two jumper resistors - R16 and R250 (the zero on them indicates they are resistors with 0 resistance - i.e. same as jumpers). It's probably best to start by removing R16 and R250, but try not to damage them since we're only temporarily removing them to narrow down where the short circuit is. Here's how to proceed:

a) First remove R16, then measure again between the cathode of D10 and ground. Still getting 21 Ohms on the 200 Ohms scale?
-If no, then the short circuit is somewhere down the line of R16. See step c)
-If yes, remove R250 and proceed to step b)

b) Measure resistance again between the cathode of D10 and ground. Still get 21 Ohms?
-If no, the short circuit is after R250. See step c)
-If yes, then the short circuit is most likely caused by one or more of the ceramic caps C12, C13, C15, and possibly C11. See step d)

c) If the short circuit is either after R16 or R250, then you will have to find all of the components that are connected to whichever of these resistors the short circuit was after and then see if the short circuit can be further narrowed down. This can be quite time consuming. I doubt this will be the problem, though, so re-check your results again. If you end up at this step again, let me know.

d) Start by removing C15, then measure resistance between the cathode of D10 and ground. If you still get a reading of 21 ohms, proceed to remove C13. Then measure again between D10 and ground. Continue doing this with C12 and C11, until the short circuit (i.e. 21 ohm reading) disappears. If it doesn't disappear, let me know.

I hope I didn't scare you with this wall of text. Doing these measurements is actually easier than you think it is.

[jetadm123]

Re: HP w2007 white screen problem

-If yes, then the short circuit is most likely caused by one or more of the ceramic caps C12, C13, C15, and possibly C11. See step d)

I hope I didn't scare you with this wall of text. Doing these measurements is actually easier than you think it is.

If one of the caps is shorted, how did you determine the value for the replacement? Most of the SMD ceramic caps are unmarked. Did you just use the datasheet for the AAT1164C as a reference?

[pcjiet]

Re: HP w2007 white screen problem

"1" on the left hand side means out of range or infinite. This verifies that your fuse is bad.

As for the other voltages especially the 6V, the caps on that 5.1V rail could be bad? You could try replacing all the caps on 5.1V rail. The caps will be probably 1000uF 10V.

I replaced those 3 caps, they are 100uF 16v each, but the multimeter read the same voltage 6.3 v. What could it be? or may be this is the correct voltage?