HP 2007W LCD Monitor

[Spork Schivago]

Hello everybody. Thanks for taking the time to read this. We have an HP 2007W LCD monitor. For a while, it has been broken. I opened it once up and looked for exploded capacitors and couldn't find any. I've come a little further with my understanding of electronics and decided to open it open again. The monitor, when turned on, is completely white. It can be turned off. The menu buttons do not work. It does not display any messages saying that there's no signal. There are two boards that I believe could be at fault. I do not know the official name of these boards. One is the board that the power cable plugs in to. I will call this board the power supply for now. The power supply connects to the other board. This board has the DVI and VGA connections on it and connects to the LCD screen. I went through and desoldered the capacitors and checked them with my DMM to the best of my abilities. I do not have a capacitor tester. For the smaller electrolytic capacitors, I could test fine. For the bigger ones, I had a bit of trouble. Anything over 100 microfarads is too big. I can see if it takes a charge for the most part though. I have been checking the resistance as well. For one of the caps, my multimeter never reads OL. And the resistance goes up to around 400k and then starts slowly going down. I believe this is the capacitor at fault. It is a 680uF 10v MC series Su'scon capacitor. The number 0736(M) are on this capacitor. On their web site, they said it was a low impedance radial electrolytic capacitor. I am having trouble locating a replacement. It seems that most of the bad capacitors I have run into lately have been these Su'scon's so I would like very much to not purchase another one. I'm just not too certain with what would work. I downloaded the data sheet and think I might have some of the specs right. I'm just afraid if I get them wrong, I will end up damaging my monitor. Could someone please take a look at the capacitor I mentioned and point me in the right direction? The website to the capacitors series is http://www.su-scon.com.tw/en/product...r-105C/MC.html The PDF I downloaded that have the information in it is attached. Thank you for your help and sorry for such a long post.

[retiredcaps]

Re: HP 2007W LCD Monitor

The monitor, when turned on, is completely white.

There is a panel board that runs the entire length of the lcd at the top of the monitor. Sometimes there is a small SMD fuse. It could be open which causes a white screen. A good fuse should measure less than 1.0 ohms.

You should also reseat and clean all your connectors with isopropyl alcohol. Sometimes it is just a loose cable.

I went through and desoldered the capacitors and checked them with my DMM to the best of my abilities. I do not have a capacitor tester.

A multimeter with a capacitance function can measure the capacitance. However, no multimeter can measure ESR (equivalent series resistance). For that you need another test device called an ESR meter.

Thank you for your help and sorry for such a long post.

We have no problems with lots of quality information. Just use the enter key once in a while there are paragraphs (plural) which makes it easier to read.

edit: We also ask people to post clear focused top down view pictures of all their boards. Follow the instructions in my sig file below exactly.

[budm]

Re: HP 2007W LCD Monitor

retiredcap is correct about possibility that the surface mounted fuse on the T-CON board may have blown, or it is not getting the 5Vdc feeding it from the logic board through the switched transistor.
Please see the PDF and pictures and also read my guides.
Also see more pictures here:
http://s807.photobucket.com/albums/y...HP/HP%20W2007/

[Spork Schivago]

Re: HP 2007W LCD Monitor

Retiredcaps and Budm, Thank you for the reply. I could not locate the SMD fuse. I looked at the labeling and didn't find anything that said Fxxx. I did not carefully look at each component and compare them to a picture of an SMD fuse. I will do that soon.

I believe the connections are good from the monitor to the PC's. I have tried the VGA and DVI connections with multiple computers. The cables I have are protected with a dust sleave on each end.

Here are the pictures of the two boards. I'm not sure of the official name for the board that provides the power so I named it "Power Supply Board". Also, I did not take any pictures of the T-CON board. If it is needed, I will take one though.

I am aware that a ESR meter is needed to measure ESR. When I test capacitance for a capacitor over 100μF (maybe it's 40, I cannot remember), my DMM will read OL. When I test the 680μF capacitor, it never makes it that high. It will jump around a bit.

From my understanding, I can also test for shorts using an ohm meter. For small caps, it should read open (OL), for larger caps, it should show low empedance and then jump real high real quick like. This 680μF cap doesn't do this. It makes it to around 400ohm's and then starts going down. I do not know if this means it is leaking or not.

One last thing, the 680μF capacitor is not exploded or anything but when I desoldered it, there was this almost rusty looking colour on one of the terminals. I am not trying to say that the capacitor is the reason this LCD isn't working or that it is in fact bad. I really appreciate all of the help. I just thought I should mention this. Just let me know what else I can do. Thanks.

P.S. - I have been looking at the Atlas ESR70 meter. Do you guys think this is a good meter and if it's worth having one around? How important is being able to test the ESR of a capacitor to determine if it's good or not?

[budm]

Re: HP 2007W LCD Monitor

We do not see the pictures!

[Spork Schivago]

Re: HP 2007W LCD Monitor

Sorry, forgot to post the pictures!

[retiredcaps]

Re: HP 2007W LCD Monitor

You have 2 voltage regulators on the logic board (circled in red).

1) What is the part number of each?

2) What is the DC voltage of each pin with respect to ground?

3) Post a picture of the panel board as well so we can suggest test points.

[budm]

Re: HP 2007W LCD Monitor

Please see the PDF.
No pictures of the T-CON board?

[Spork Schivago]

Re: HP 2007W LCD Monitor

Okay, so on the T-CON board, I was looking next to the ribbon cable connector and noticed an SMD that is labeled F5. I tested the resistance and it measured open. I believe this is the fuse. It is above pin 29 and 30 of the ribbon cable connector.

I am attaching a picture of that section of the board. I can also send a picture of the whole board but I doubt anyone will be able to see anything in detail because of the limitations for the file uploads.

If this is the fuse? If so, any suggestions on a replacement?

[budm]

Re: HP 2007W LCD Monitor

That is it! the main VCC fuse feeding the T-CON board. You should Ohm out the top end of the fuse and Pin 32 which is Ground to see if it shows shorted circuits, the shorts can also be after the active switches that may not show up with the Ohm meter connected to the fuse.

[budm]

Re: HP 2007W LCD Monitor

You can set your DMM in DC amp (10A range) mode and connect the probes across the fuse then you can see how much current it draws. I usually use 1 Ohm Metal Oxide resistor in place of the fuse to try it out, then measure the voltage drop across the resistor then I can calculate the current draw and just double up the value of the current reading for the fuse rating.

[Spork Schivago]

Re: HP 2007W LCD Monitor

You have 2 voltage regulators on the logic board (circled in red).

1) What is the part number of each?

2) What is the DC voltage of each pin with respect to ground?

3) Post a picture of the panel board as well so we can suggest test points.

I was getting ready to measure the voltage on the regulators. The part number for the smaller one is az1117d-1.8e1. I believe for the larger one it is 1084-33. 0736AL is below 1084-33.

I plugged in the power cord and turned it on. There was a noise like someone touched two hot wires together. There was a smell of smoke and I'm almost certain I damaged the power supply board of my system.

I believe the four plugs that plug into the side of the power supply board were plugged in to the wrong holes. I think these plugs are for the CCFL lamps. There's two groups, with two plugs in each group. I believe in both groups, I switched the plugs on accident. I plugged plug 2 into the plug 1 hole and vice-versa. Same with the second group.

I have no idea what I'm going to do now. I physically can't see anything wrong with the board. It was the board that was sparking. I don't know if I fried the lamps or what. I don't even know if this is what caused it. Just one of those days I guess.

[budm]

Re: HP 2007W LCD Monitor

Oooh, you are not suppose to run the inverter without the load, since those connector will have about 1500~2000Vac on them, probably arc over the terminals. Look and see if you can see any carbon traces, scrape them off real well. The Inverter may have gone into shutdown fast enough to protect itself, the inverter has detection circuits that detect no load or overload.
Plug the lamp connectors back in securely and try powering them up again.

[Spork Schivago]

Re: HP 2007W LCD Monitor

Okay, I'm a little lost here. Could you explain what you mean by not running the inverter without the load? I never had any formal training or anything with electronics. I've just kinda taught myself what I know by experimenting and reading stuff on-line and in books.

[Spork Schivago]

Re: HP 2007W LCD Monitor

I've decided to go to bed. It's 2:30 here. I'll take a look at it tomorrow. Thanks for the help again and hopefully no damage was done. The way it smelled though, I doubt it. Good night.

[budm]

Re: HP 2007W LCD Monitor

The lamps are the loads for the inverter backlights circuits.

[selldoor]

Re: HP 2007W LCD Monitor

@Budm

"Oooh, you are not suppose to run the inverter without the load"

Not sure where you got the idea the lamps were not plugged in? As I understand it he says he had them in the wrong sockets.(Right sockets but wrong oreder)

@Spork - Bummer eh! I do not think it matters which lamp is plugged into which socket - that would not cause your problem.

You may have moved it but can you recall how it was set up in particular was the panel frame touching the power board or was the power board resting on anything metallic/conductive.

I suggest taking pictures of both sides of the board - close ups of the ccfl
sockets and plugs and letting us have a look before you re-connect.





I

[budm]

Re: HP 2007W LCD Monitor

Well, I would look at his pictures on how he had them connected, or may be he did not seat the connectors all the way in.

[Spork Schivago]

Re: HP 2007W LCD Monitor

Hey guys, I had the CCFL plugs labeled with dots. 1 dot for connector 1, 2 dots for connector two, etc. I just didn't label the connectors themselves. I did however mark the metal case that the board gets screwed down to. I put the board in, figured out what was what and labeled the connectors as well.

I believe I found the problem. I had an anti-static bag on a paper folder and was placing the boards on the anti-static bag. I did not realize that the lines on the anti-static bag were conductive. I hope I didn't do too much damage.

I can say that since I took the anti-static bag out of the equation the screen lights up white still. However, I believe that is just the CCFL lights turning on.

Budm, testing the fuse with the DMM set to 10A didn't work. I wasn't really expecting it too because of the fuse being blown. Did you mean to test it after I replaced it with the 1 ohm SMD Metal Oxide Resistor?

One last thing, I have never successfully soldered an SMD component. From my understanding, I'm supposed to put resin on the contact I'm soldering the SMD component too. Then I'm supposed to put a little bit of solder on the iron instead of putting the iron to the component and the board. Is this correct? And does anyone have any good advice that could help me with replacing SMD components including desoldering and soldering them? Thanks for all the help guys!

[budm]

Re: HP 2007W LCD Monitor

"testing the fuse with the DMM set to 10A didn't work" We are not testing the fuse using AMP mode. We already know that the fuse is blown. We want to power up the T-CON board using the meter in DC AMP mode.
You are basically jumping the open fuse with the Meter (set to DC AMP mode, the Red probe on the meter will also have to plugged inot the AMP probe inlet if the meter has separate V/Ohm and AMP input, the meter will show how much current the T-CON board is flowing, or you can use 1 Ohm instead of using the AMp meter.
Picture of your meter may help.
RED probe on one end of the fuse, Black probe on the other end of the fuse.