Dell 3008wfp faulty power supply

[Agent24]

Re: Dell 3008wfp faulty power supply

You may be correct with the idea that something else was damaged due to the shorted cable.

I looked up data on the LVDS interface and realised it carries not just signalling but power to the panel as well, shorting the data lines to the power rail might indeed damage something.

But first what else have you checked? And what is the current fault symptom?

[valkyr]

Re: Dell 3008wfp faulty power supply

Thank you for your persistence in the troubleshooting of this issue. I really do appreciate it.

Currently, I did only a visual check of all the components, on each board. Nothing looks discoloured or bulging. I haven't done any multi-meter testing, as I am not quite sure where to start.

The symptom is, monitor responds to power button. When I turn it on, I can see the back light power on, the screen is dark (but lit up), and I have no display. I should expect to see a Dell Splash logo, or even menu selection when I press the menu button. But nothing displays.

[Agent24]

Re: Dell 3008wfp faulty power supply

I'm not sure how much I can help given the situation with the LVDS\TMDS(?) cable and what it may have caused, but I will give it a try.

First of all if you can take some good photos of the boards and upload them that will greatly help. It's hard to get a general idea of the circuits when we can't see them. It also helps show potential problems you may have missed. Some things are not obvious if you haven't seen them before, for example.

Then I would suggest you start with measuring all the power supply rails and ensure they are within spec. This would also include any secondary regulators on the logic boards. Additionally, checking any fuses which may be present on the board(s). (This is where the photos come in handy to help with identifying these)

[valkyr]

Re: Dell 3008wfp faulty power supply

Sorry for the late reply, I have pictures now, some are better than others, let me know which one you would like to get a closer look at.

[valkyr]

Re: Dell 3008wfp faulty power supply

Also carrying on.

[Agent24]

Re: Dell 3008wfp faulty power supply

I notice two SMD fuses on the T-CON board, if the cable shorted, they might have blown. I have marked them (F1 and F2) in the photograph. I would check those to start with.

[valkyr]

Re: Dell 3008wfp faulty power supply

Good Eye

Sorry I haven't responded in a bit, been on vacation.
I had a chance today, tested with a multimeter and the F1 fuse looks to be the culprit. I lightly soldered a connection to bridge it for a test, and booted up the monitor.
And... Display!

A very bad and weird switching between a full white screen; a half screen with a very messed up display, and the other half black.

I took a picture.
It's a step in the right direction, tho not sure if it's repairable yet. Going to research these symptoms next.

If my understanding is correct, the F1 is simple on or off, so my solder job wouldn't be the cause would it?

[Agent24]

Re: Dell 3008wfp faulty power supply

Yes, a fuse which is intact looks to the circuit for all intents and purposes as another piece of wire. So replacing it with a blob of solder would make no difference. You can always check by measuring the voltage on each side of the fuse and they should be the same.
One thing however, you should really check there are no shorts first before jumpering a fuse (Sorry, I should have mentioned it before), but since nothing went up in smoke, it's probably OK.

It's possible something on the TCon board has been damaged and leading to the picture corruption.. it's also possible your repaired cable is not in good enough shape to cope with the high speed data signalling required.

You could at least try checking the regulators on the TCon board and ensure they are putting out the correct voltages - these look like U6, U7, U21 and U22, and maybe U23. If you aren't sure how to check, give the part numbers for each of those.

But possibly someone else will have better advice when they see the picture fault you posted.

[ZZZiltoid]

Re: Dell 3008wfp faulty power supply

Hey, my Dell Story looks like this: Screen stoped working, but the blue power light still works, can switch it on and off (it wont turn yellow though without any input cable attached). Screen does absolutely nothing, no backlights, no menu, no flashing.

Before I came here I read about the recurring power supply problems, so I ordered a new one: http://www.super-laptop-parts.com/fo...5-p-19615.html
I replaced it, and.... nothing. Even the power light stopped working. I even checked if maybe I broke somethign during disassembling so I put the old supply back in and the power light is back again.

So first off I guess I can safely assume that my new power supply is broken?

I'll return with photos, any parts I should focus on?

Btw Maxidud2000 described the same problem but never returned to say if he managed to fix it. Other people with the power light issue all seemed to have working backlights.

[Agent24]

Re: Dell 3008wfp faulty power supply

To start with, check all the power supply output voltages and any control signals going to it.

Post good clear photos of both sides of your boards if you can, sometimes others can spot things you may have missed.

[mozg1986]

Re: Dell 3008wfp faulty power supply

And somebody knows parameters of lamps in this monitor? Mine it becomes bad, it is time to change, but I don't want to open the panel once again

[stj]

Re: Dell 3008wfp faulty power supply

check the length of the panel inside,
then go here for tubes or an led kit
http://stores.ebay.com/lcd-led-parts

[vika]

Re: Dell 3008wfp faulty power supply

I'm trying to save 2 screens found in trash;
One solved with your help about the diode Thanks !

But the other one is giving me headaches:
Does this seems like a bad T-con board ?
Video of the screen booting

The picture is scrambled as you can see but the "no source" text is visible and disappearing as usual, this is why i'm guessing it's a t-con board issue.

[vika]

Re: Dell 3008wfp faulty power supply

Ok so I swapped the T-con board with a good one -> same problem
Then I swapped full mainboard + PSU (including cable) with a good one -> same problem

So I think this screen is not repairable.

[TTLKurtis]

Re: Dell 3008wfp faulty power supply

Thanks for the link. I had already seen the video, just was not sure if it was useful for the 3008, as the video is for the 3007. Will use it as a guide.

Yeah the disassembly seems to be different on my 3008WFP than it is on the 3007WFP... Can't figure out how to get the back off now that I have the front off (except the power ribbon is still attached to power button, is that removable somewhere I'm not seeing?...

[TTLKurtis]

Re: Dell 3008wfp faulty power supply

Hi everyone, new to the forum. Been looking through this thread because I was given one of these monitors the other day. Nothing happens when the power button is pressed so I have ordered the replacement diode.

I was wondering if someone may be able to help me, I am having an absolute nightmare trying to open this thing.
I have managed to separate the bezel so that it's just held on by the power button cable then I flipped the monitor over.

On the side with the card reader the panel drops out fine (just gets stuck on the card reader).
On the other side the panel barely moves and seems to be stuck in the corner above the power button but does drop out on the corner where the power button is.
I have tried heating this area with a heat gun in case there was some kind of adhesive there but it didn't help.

I have circled the area where it's getting stuck in the attached picture.
Any help/advice would be greatly appreciated, thanks.

Can you explain how you got the back panel off? Do you do the same credit card / prying technique where the back metal meets the plastic glossy frame on the sides? The 3007WFP video isn't helpful here because it's different.

I also am not sure what to do about the power button ribbon cable. Front is detached and separated with cardboard, monitor upside down, but that cable is still attached.

[TTLKurtis]

Re: Dell 3008wfp faulty power supply

Alright so I've got the back panel off... What a pain in the ass. Once you pop the front panel off, you don't remove the ribbon but you kind of yank on the front panel a little to give you some more slack because it's taped down. Now you can rotate the front bezel around a little bit and there are (4) medium black screws in the corners, then (2) small black screws on the left, (4) small black screws on the bottom, (3) small black screws on the right, and (4) small black screws on the top. They're kind of hard to get to, you need a small screwdriver and then I had to use good tweezers to grab them because my screwdriver's magnet was too weak to do the job.... Now I have the back panel visible with all the metal and stuff... this is where it gets interesting I'm sure.

[TTLKurtis]

Re: Dell 3008wfp faulty power supply

All the way to the power board now, I have the 4 screws on the back side and the 5 screws on the front side removed, and I can't seem to pull the board out. I'm hoping it's just sticky tape or thermal paste on the heatsink that's not letting me pull it up, and maybe I can try a hair dryer tomorrow to warm it up and get it to come off easier...?

[TTLKurtis]

Re: Dell 3008wfp faulty power supply

Well that stinks... managed to finish the repair today, taught myself how to desolder and solder. Got the diode replaced and put everything back just as it was... Unfortunately, it's still doing what it was doing before I started the repair. You hit power button and the lamps are obviously on and the power button glows blue, but no picture is displayed, you can't bring up menus, nada... =(

Guess I'm going to have to buy a new monitor after all.

[Lumberjack777]

Re: Dell 3008wfp faulty power supply

Sorry I came in late on this one. Sometimes when you reassemble the 3008 as you lower the big heat shield back plate you have to tuck your fingers inside and attach the 2 video cables. It's common for one to come a little loose as you attach the 2nd one. I'd go back and make sure those 2 cables are firmly attached.