Dell 2007FPb - No power at all

[slawson2000]

Re: Dell 2007FPb - No power at all

Maybe replace ALL the capacitors? Anyone?

[craftsman1234]

Re: Dell 2007FPb - No power at all

There are 2 test points at the bottom side of the board, TP711 (+), and TP712 (-).
just put your DC meter probes on those two points. Just do not touch anything in the hot side of the board (heat sink, traces, etc.)

budm,

I have posted in another thread regarding the inverter board that may have been lost due to a short on my FPb. I'm looking at keeping the screen/case and power/supply for parts. I have replaced all the caps on the PS including the large one. I'm wanting to make sure that the PS is working correctly. It appears to be. I have tested TP712 and TP711 like you have shown. Do I also need to test near CN702. If so what pins? Your above diagram was very helpful but I have not found one for the backside of CN702.

Very noob here.

TP712 & TP711 = 19.12 volts
The very large capacitor = 167.2 volts

Thanks.

[budm]

Re: Dell 2007FPb - No power at all

You do have correct voltage output of the main power supply board. You will need to check and see if the 3.3v, 5v, 12v is working or not (you do not need to have the inverter board connected).
More photo here:
http://s807.photobucket.com/user/bud...?sort=3&page=1

[craftsman1234]

Re: Dell 2007FPb - No power at all

You do have correct voltage output of the main power supply board. You will need to check and see if the 3.3v, 5v, 12v is working or not (you do not need to have the inverter board connected).
More photo here:
http://s807.photobucket.com/user/bud...?sort=3&page=1

Here are the results.

12v = 0
5v = 5.18v
3.3v = 3.37
19v = 19.11v on the main pc board

I was not sure what the photo meant for the 19v on the USB/Soundstick. Do you mean going to the ground/from the main power plug? I see the one point to connect the meter to. I dont want to short anything.

I forgot to add that when I got another (working) monitor this weekend I took out the inverter and used it in the non-working one. The non-working monitor powered up. I could access the menus change color setting etc. When I used a DVD with s-video the picture was what I would call digital colored lines going across the screen that changed with what was probably playing on the DVD. Unfortunately I did not get a picture and don't know if it is the DVD or the monitor that was causing the lines.

[budm]

Re: Dell 2007FPb - No power at all

As long as you get the 19V, the main power supply is working, you are also getting the 3.3 and the 5v. Not sure about the 12v, but this 12v is used for the DC output jack for the Dell external sound bar powered speakers.
So do you get the line on the screen when you use it as PC monitor?

[craftsman1234]

Re: Dell 2007FPb - No power at all

You do have correct voltage output of the main power supply board. You will need to check and see if the 3.3v, 5v, 12v is working or not (you do not need to have the inverter board connected).
More photo here:
http://s807.photobucket.com/user/bud...?sort=3&page=1

As long as you get the 19V, the main power supply is working, you are also getting the 3.3 and the 5v. Not sure about the 12v, but this 12v is used for the DC output jack for the Dell external sound bar powered speakers.
So do you get the line on the screen when you use it as PC monitor?

The entire screen was filled with scan lines top to bottom multi-colored. The DVD worked after that on my working 2007's.

It powered up with the Dell logo all the menus for color adjustments worked. The symbol that showed what screen setting you were in worked for all the modes (top left corner).

The computer I planned to use it with outputs only composite and s-video. When I powered it down to move it to plug it into the computer the screen would not turn on. Thought I had blown the working inverter. So I took it apart and put the inverter back in the monitor it came from. Everything powered right up it this one.

[budm]

Re: Dell 2007FPb - No power at all

Wells, that does not sound good, looks like you have more than one problem beside bad inverter board.

[craftsman1234]

Re: Dell 2007FPb - No power at all

Wells, that does not sound good, looks like you have more than one problem beside bad inverter board.

Yep, I'm really just hoping to save the screen, case and power supply. The inverter board is toast. It burnt right through the traces. I'm guessing that this got hit with a pretty good power surge.

[craftsman1234]

Re: Dell 2007FPb - No power at all

Yep, I'm really just hoping to save the screen, case and power supply. The inverter board is toast. It burnt right through the traces. I'm guessing that this got hit with a pretty good power surge.

Been testing the DVD. It is acting up. Powers off after a few minutes of playing. Maybe the 2007 boards are okay except for the 12v. It did not display the same pattern that I saw on the 2007 though.

[slawson2000]

Re: Dell 2007FPb - No power at all

Glad to see there has been some activity here, I got side tracked with other issues. I have not made any progress, but picking up from post #43 above, I get
19v = 19v
12v = 0v
5v = 0v
3.3v=0v

Any new thoughts?

[slawson2000]

Re: Dell 2007FPb - No power at all

Is this thing on?

[zero10]

Re: Dell 2007FPb - No power at all

Your main USB board is not working properly, you likely have one of a few problems there:
Blown fuse (there is one big fuse on it, white ceramic with gold ends labelled 3A)
Bad diodes (FD7, FD8, etc.)
Bad resistors feeding the switch mode power supply controller (probably the ones entombed in silicone near the top of the board)

This board turns 19V into 3.3/5/12V for the rest of the monitor. To have the power buttons work you need the 3.3V to be on, and for the panel to work you need the 12V supply. As far as I can tell the 5V is just for USB stuff and won't affect the monitor (I'm running a pair of 2007wfpb monitors with no 5V right now)

These things have been covered in the other dell 2007 threads on this forum - I think they have been linked in here already but I might be confusing this thread with another

[slawson2000]

Re: Dell 2007FPb - No power at all

zero,
Thanks for the response. I have looked and am not finding what I need. I am not the most knowledgeable but can test things if I follow directions. I have no idea what the tests might be.

Did you find a thread that did a step by step for the main usb board?

[budm]

Re: Dell 2007FPb - No power at all

See post 2: pictures of the diagram
https://www.badcaps.net/forum/showth...highlight=2007

[slawson2000]

Re: Dell 2007FPb - No power at all

Thanks, have seen those pics/diagrams before, just not sure what to do.
I followed budm's link to photobucket pics for the 2007FPb pics and tried to measure the violated written on the circuit board. As for the diagram two if those points correlate to the labels written on the circuit board (C44 and C60), but I cannot find a C58.

Putting multimeter to the fuse, I get 0 ohms. I assume that means it is okay.

Testing the diodes I got from this link. Not sure if it is correct or accurate.

http://techsci.msun.edu/strizich/EET...bs10-1-2-3.pdf

All readings were infinity and around 550 ohms. Not sure if that is right or I just have a cheap meter.

No idea how to test the resistors.

What to do?

If I found another board would the monitor fire up again? I do not mind buying another board if that truly would fix it, but I do not want to throw money at this with no results either. Maybe this is the option for me?

I dunno...