HP W2408 Problem

[sprocket]

I was given a HP W2408 monitor that doesn't work and I thought I'd try and fix it.

When plugged in, after about 2 seconds the on/off button turns blue and stays that way but no picture or text when booting the computer.

No effects of any kind when any of the Menu + - etc. are pushed.

Whats my problem and where do I start ..

Thanks sprocket

[PlainBill]

Re: HP W2408 Problem

I was given a HP W2408 monitor that doesn't work and I thought I'd try and fix it.

When plugged in, after about 2 seconds the on/off button turns blue and stays that way but no picture or text when booting the computer.

No effects of any kind when any of the Menu + - etc. are pushed.

Whats my problem and where do I start ..

Thanks sprocket

You start by taking it apart and taking two pictures of the power supply, one of the power supply from drectly over the top side, one from directly above the bottom side. We want them clear, well lit, and at least 1000 x 1000 pixels resolution. Attach the pictures using 'Manage Attachments' - below the text entry area.

PlainBill

[sprocket]

Re: HP W2408 Problem

OK here are the HP W2408 Power Supply Board

[PlainBill]

Re: HP W2408 Problem

OK here are the HP W2408 Power Supply Board

Good pictures, and they give me a little information. This is a slightly unusual configuration for a power supply in a 24" monitor, usually I expect to see main and standby supplies. Physically, the caps look good, so lets move on to the next step.

I'm going to need two more pictures. The first is an overall shot of the circuit boards hooked up to one another in more or less the normal way. The second is a picture of the top of the inverter. On the inverter one I would like good detail on the area around the connector for the cable from the power supply.

By your description, there is no sign of backlights. Please confirm that.

PlainBill

[sprocket]

Re: HP W2408 Problem

Here is 3 more pictures

No back lights, can't see any image or menu using a flash light

I have a Blue ESR and checked all caps, they all seemed to compare with new ones I have here in my hobby room

I Have eye balled for burnt, cold solder etc. but that as far as I have gone.
I don't savvy the working flow of these very well and without schematics, I'm lost

I have never seen this unit working, so don't know if it's supposed to say (NO SIGNAL) or what when just plugged in without computer

[alexanna]

Re: HP W2408 Problem

If I am not mistaken this monitor is using the same inverter as the Gateway FPD2485

https://www.badcaps.net/forum/showth...eway+24&page=3

[PlainBill]

Re: HP W2408 Problem

Here is 3 more pictures

No back lights, can't see any image or menu using a flash light

I have a Blue ESR and checked all caps, they all seemed to compare with new ones I have here in my hobby room

I Have eye balled for burnt, cold solder etc. but that as far as I have gone.
I don't savvy the working flow of these very well and without schematics, I'm lost

I have never seen this unit working, so don't know if it's supposed to say (NO SIGNAL) or what when just plugged in without computer

The pictures give me a lot of information, and some points to check. Let's start with those.

First of all, the inverter is PROBABLY getting 24V on the input and producing something over 1000 volts on the outputs, so take the Danger warnings seriously.

To simplify things, I'm going to say the red wire on the cable to the inverter is pin 1, white is pin 8. Pins 1 and 2 are power, pins 3, 4, and 6 are Gnd. The other three pins are control or status lines and there does not seem to be any clues as to what is what.

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?

While your monitor looks a lot more complex than most, all work in essentially the same way. A power supply provides DC voltages for the electronics. A signal card processes the video signal and passes it to the display. The signal card also performs control functions. An inverter provides high voltage to turn on the backlights.

USUALLY the signal card returns everything to the 'last known state'. If the monitor was 'On' or in standby when power was removed it turns on in the On state, then goes to standby if no signal is detected. If it had been turned Off by the power button, when it powers up the power LED will stay dark. One notable exception is Dell monitors. Usually if they are powered up with no computer connected they will display a test pattern.

PlainBill

[sprocket]

Re: HP W2408 Problem

C3 = 25 vdc
pin 1 = 25 vdc
pin 5 = 5 vdc
pin 7 = 0 vdc
pin 8 = 0 vdc

[PlainBill]

Re: HP W2408 Problem

C3 = 25 vdc
pin 1 = 25 vdc
pin 5 = 5 vdc
pin 7 = 0 vdc
pin 8 = 0 vdc

A couple of things to try. Hook the monitor up to a working computer, and hook all boards together. With the computer displaying a desktop, and the monitor connected to AC power, does the power LED respond when you hit the power button? Do the voltages on pins 5, 7, and 8 change when you press the power button?

PlainBill

[sprocket]

Re: HP W2408 Problem

All hooked up just like it was running with XP working, pressing the power button makes no change to voltages at 1, 5, 7, or 8, they stay as above post

I watched the screen when using WinKey u u to shut down and not a trace or flicker of anything

I did make sure there was continuity from 7 and 8 to the other boards and no bad connectors

[PlainBill]

Re: HP W2408 Problem

All hooked up just like it was running with XP working, pressing the power button makes no change to voltages at 1, 5, 7, or 8, they stay as above post

I watched the screen when using WinKey u u to shut down and not a trace or flicker of anything

I did make sure there was continuity from 7 and 8 to the other boards and no bad connectors

To check one thing - as you press the 'Power' button, does tehe Power LED turn on and off? If it does not, I would like a picture of the signal board.

PlainBill

[sprocket]

Re: HP W2408 Problem

No the power light does not go off and on

When first plugged in, the light blinks real quick then off and in about 2 seconds comes on steady and stays there.
I left it on for about 30 minutes once to see if it might change color to amber but it did not

Seems like it is in the off/on circuit huh ..

I really appreciate all your time on this .. Man your dedicated

[PlainBill]

Re: HP W2408 Problem

No the power light does not go off and on

When first plugged in, the light blinks real quick then off and in about 2 seconds comes on steady and stays there.
I left it on for about 30 minutes once to see if it might change color to amber but it did not

Seems like it is in the off/on circuit huh ..

I really appreciate all your time on this .. Man your dedicated

Not the On/Off circuit, but there is a problem on the signal board. There are only a few things that can be checked on this board. U102 is a 3.3 volt regulator, check the output voltage. Likewise, across the board, check U117. Just to the left of U117 is U109. What is the number on that IC, and what are the voltages on the pins?

PlainBill

[sprocket]

Re: HP W2408 Problem

U102 pin1=G pin2=5v pin3=3.3v

U109 don't have much for a number, PB77 is all
pin 1 I assume gnd I get 3.3v on both pin 2 & 3

U117 I get zero on all pins which I think is another 3.3 reg ??

[PlainBill]

Re: HP W2408 Problem

U102 pin1=G pin2=5v pin3=3.3v

U109 don't have much for a number, PB77 is all
pin 1 I assume gnd I get 3.3v on both pin 2 & 3

U117 I get zero on all pins which I think is another 3.3 reg ??

What are the numbers on U117? I can read the first part of the second line, but not the stuff after the dash.

PlainBill

[sprocket]

Re: HP W2408 Problem

As1117l-33
b0727 42

[alexanna]

Re: HP W2408 Problem

I know it can't be this simple.
On the signal board I see some components marked FS101-FS104 with a G stamped on them, Are those fuses?

[sprocket]

Re: HP W2408 Problem

Yes they are and ohm out good (closed)
I also see Q110 pin 8 is connected to U117 and it has 4435CW 729156 (the C could be a G) on it
I tried to find what it was and came up with a Fairchild SI4435DY anyway the pins ohm out like it (6,7,8 tied together etc.)

if that's any help

I won't do this if you don't want me to, I don't want to mess something up

I powered it back up and found zero voltage on either end of all the fuses you refer to
I see pin 3 of U117 hooked to pin 8 of Q110 and maybe all 5,6,7,8
I did a voltage check on Q110 and from chassis gnd pin 1,2,3,4 reads 5vdc
pin 5,6,7,8 reads zero

I don't know what Q110 is and what it should but was hoping it supplied 5vdc to U117

[PlainBill]

Re: HP W2408 Problem

Yes they are and ohm out good (closed)
I also see Q110 pin 8 is connected to U117 and it has 4435CW 729156 (the C could be a G) on it
I tried to find what it was and came up with a Fairchild SI4435DY anyway the pins ohm out like it (6,7,8 tied together etc.)

if that's any help

I won't do this if you don't want me to, I don't want to mess something up

I powered it back up and found zero voltage on either end of all the fuses you refer to
I see pin 3 of U117 hooked to pin 8 of Q110 and maybe all 5,6,7,8
I did a voltage check on Q110 and from chassis gnd pin 1,2,3,4 reads 5vdc
pin 5,6,7,8 reads zero

I don't know what Q110 is and what it should but was hoping it supplied 5vdc to U117

A masterful analysis. Tentatively I would say the Q110 (and U117) provide voltages for the USB port and support ICs.

PlainBill

[sprocket]

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?