Dell 2007FPB teardown

[Behemot]

Re: Dell 2007FPB teardown

It's burned too close to the ground, replacing won't fix that. Besides, there is almost nothing left from the copper pad, where would you like to solder it??

[stj]

Re: Dell 2007FPB teardown

buy a new connector - and sand away all the carbon on the board.

[Behemot]

Re: Dell 2007FPB teardown

That's not safe to use any longer. I am afraid you will have to remove the inlet, clean as much as you can, drill out the burned stuff and solder IEC C14 cable in the two good positions and somewhere further on the single bad position (maybe on the fuse directly). Than somehow firm it in position so nobody tears it off.

Or you can cut piece of the board out and than place a new one in there with some epoxy, but that's too much of a work if you ask me and I am still not entirely sure it would be safe on full AC input voltage…

[budm]

Re: Dell 2007FPB teardown

You had bad solder joints on the AC inlet to the circuit board, clean off all the carbon deposit and resolder all 3 pins and inspect the board for bad solder joints.
Common problem.

[rdagger]

Re: Dell 2007FPB teardown

Loud crackle and smoke today. Serious scorch marks on the board by the outlet (see pics), but I don't see any other visual signs or bad caps. Anyone have any insight into which parts may be the culprit?

[huge]

Re: Dell 2007FPB teardown

Behemot, it sounds like you need to start a new thread. If you have some time, you could start a FAQ on troubleshooting lack of one rail when the others are working.

[Behemot]

Re: Dell 2007FPB teardown

Still have not found anything. All the resistors check fine and have same value as resistors in the same position of the second PWM controller which works fine providing both +3.3 and +5 V. But the +12 V is jsut still not there. Something is making the PWM go into 0 % switching mode.

[Bungz]

Re: Dell 2007FPB teardown

I just did the most grimy 2.7k fix, I should have taken pictures.

Used an enormous leaded resistor lol

Works perfect now

[Behemot]

Re: Dell 2007FPB teardown

[Behemot]

Re: Dell 2007FPB teardown

So the DTC for the +12V part of the TL1451 is at 2.44 V which means it is at 0 duty cycle. I think the problem is here.

I have checked all the corresponding SMD resistors and tiny SMD transistors around other TL1451s and all of the values are the same. So it seems those are OK. That really leaves me with bad TL1451 only?

Replaced TL1451 from scrapped display, no change! Bloody hell this PoS.

[Behemot]

Re: Dell 2007FPB teardown

I've replaced the mosfet with another 2SJ598 with no change. Tested all the 272 resistors and they seem to be very well in spec.

ADD// Eh, guys, did these displays came in pairs? I opened the other one and everything is mirrored in there. What was right is left and vice versa. The USB board has all four channels with four DC-DC modules.

[Behemot]

Re: Dell 2007FPB teardown

Ping? Any idea?

[Behemot]

Re: Dell 2007FPB teardown

Got a problem too with these. The owner plugged the speaker bar into runnign display, boom and monitor was not turning on since. He tried another one, plugged while off, turned on and the same.

I opened one, the 3A fuse was burned. Replaced it and I got image with +3.3 and +5 V rails, but the +12 V feeding the speaker is not there. Transistor is not shorted, however, it has 19 V on both source and gate, also there is 19 V on those small SMD transistors nearby the side USB connectors. Should I try to replace the FET or something else?

Speaker does not seem to be bad however, I hooked it to old AT supply and it seems to be working normally, drawing like 0.01 A while playing nothing.

[awkeye2003]

Re: Dell 2007FPB teardown

I also want to thank everyone here who troubleshooted the Dell 2007fpb power problem and about the solution with the resistor 2.7k fix. Worked like a charm for me!

[selldoor]

Re: Dell 2007FPB teardown

iw4egx please start a new thread - this thread is meant to be for
reference only

[iw4egx]

Re: Dell 2007FPB teardown

Hello to everyone, i'm new in this forum and have a dell 2007fpb that will not power on, i've used for 3 years without problam, a day...died.
I've opened it and have the 4 boards blacklight, power supply, control board and 12v board.
For check the PSU voltage where i have to test voltage and between what pins?

[tweety]

Re: Dell 2007FPB teardown

Another fix changing the resistor under the white glue. My second monitor failed in the same way as the first. So now they have both had the same fix about 3 months apart.

AC21 you're a real star ! Thanks also to KALMARA.

So if you're not working. First place to look is under that glue. 2 for 2......

[Zoltar]

Re: Dell 2007FPB teardown

HI FRIENDS!!

I'd like to mention that replacing the 272 resister with another 2.7K worked a treat. I can now check sites!

I wonder if there was a bad batch of resisters or maybe a cold solder joint? I spoke with a friend who has much more electronics knowledge and he mentioned that he rarely sees resisters fail, and when they do they usually burn up.

Thanks to all who did the grunt work on this!

[sahardgk]

Re: Dell 2007FPB teardown part 2 pictures

More pictures.

Thanks very helpful.

[gamal]

Re: Dell 2007FPB teardown

اشكركم جميعا