Dell 2007FPB teardown

[TS200010]

Just wondering what the best way is to remove the white gunk over the components on the USB/Buck board... is there a solvent perhaps?

[Behemot]

Re: Dell 2007FPB teardown

I'd say, 1-2 amps?

[dariolana]

Re: Dell 2007FPB teardown

Ok, thanks for your reply...any guess idea how many amps should be able to withstand this buck of 3.3v?

I am waiting for parts, will try to replace and see of works, plan B is go with the buck converter.

thanks again.

[Behemot]

Re: Dell 2007FPB teardown

in principle, why not

[dariolana]

Re: Dell 2007FPB teardown

Hello, I am trying to repair this monitor that blown the 3A fuse...Just doing some testing on other components and thinking about this picture that found on the forum

https://www.badcaps.net/forum/attach...2&d=1318649339

Based on that the 12V are for the speakers, the 5V are for the USB, could be possible to just scrap the board and just replace it with a buck converter for the 3.3V, just to make it work as a monitor, no USB, no speakers...

Please let me know your thougths...

Regards

Dario

[Behemot]

Re: Dell 2007FPB teardown

don't think there was any manual available ever

[alijeep]

Re: Dell 2007FPB teardown

Hello good time
I am a repairman
I am requesting a manual service for this monitor (Dell 2007FPB), especially the schematic of the power board, and the value of the R623 resistor that has burned is not clear, and it is not clear in your pictures either.
I have been suffering from this problem for a long time and I could not fix this monitor.
please guide me
Thank you very much for your cooperation

[Kobok]

Re: Dell 2007FPB teardown

Dear Badcaps, Behemote,
Additional burnt problem here: In my 2007WFPb the IC601 blown up (and some other resistors too). The resistors have been identified but the IC601 complete unreadable. Shall I use 2407 schematic as reference or anyone can give me the written code. I would appreciate.

[WB1]

Re: Dell 2007FPB teardown

A second 'thanks' to the forum and its members - another SMD resistor on the USB board failed and was replaced - R52 47K this time !

It lives again !

[Behemot]

Re: Dell 2007FPB teardown

That other heatsink, Q601 and per the marking system, IC601. If there is no short after removing the rectifier, replace that with a good one and check it with incandescent light bulb connected in series with the power supply just to be on the safe side.

[Fr0sT]

Re: Dell 2007FPB teardown

OK so I've replaced the bridge rectifier and the fuse and now the monitor is up and running, thanks for the help.

[Fr0sT]

Re: Dell 2007FPB teardown

Yes, I shorted it while connected to the grid

Anyway I've taken the capacitor off the board and now there is no resistance, it's not shorted so I guess it's ok.

Bridge rectifier BD601 - each pin is shorted with each pin (measured it while removed off the board), + and - pins have some burnout on them (see attached pic) so I guess it's dead ?

Fuse F601 - measured it taken off the board and it's open circuit so it's also dead.

Which are the switch and controller elements ?

[Behemot]

Re: Dell 2007FPB teardown

Capacitor does not seem to have any problem, you've just discharged it via short. If it was plugged in the grid during that, than surely fuse and the bridge rectifier BD601 went out if you measure it shorted. Take it out and take measurement again to see whether also the switch or controller are fried, or just the rectifier itself.

[Fr0sT]

Re: Dell 2007FPB teardown

OK I think I got the pins I needed on the power board on the connector towards the inverter (marked on the first picture). I've tapped directly on the connections from the power board towards the inverter and left the inverter board disconnected, just connected the LED driver board on it's place. All went good, the 2 LED strips lighted up when hitting the power button, I've assembled back the panel and tested it again - the "No input signal" box appeared on the screen, jumping up and down. At this point I wanted to test the brightness adjustment before final assembly and hooked the monitor to my PC but unfortunately somehow I've shorted the power board and all went out with sparks, smoke...

At first look the big capacitor seemed fried (marked in orange on the first picture), measuring it's pins with my multimeter results in 0 resistance, it also beeps on shorted circuit.

First question is can I replace it with any other 180uf 450V capacitor, I've found some in local retailers but smaller in size and temperature (85C vs 105C).

Second question is is it possible that I've fried something else besides that capacitor, any ideas what to check ?

Apologies if questions seem silly but I'm more of a computer guy and electronics has never been my strong field, still I'd want to fix that monitor.

[Behemot]

Re: Dell 2007FPB teardown

That's usually the case. If the pins are not labeled, you can always find datasheet for the inverter driver and have a look which pins are what.

[Fr0sT]

Re: Dell 2007FPB teardown

Guys,

I have a 15 year old 2007WFP, which is has been a faithful servant until recently when it developed the notorious 2 seconds to black issue. I've taken it apart along with the panel and when powering it up one of the six CCFLs does not light up, the other 5 light up and shut down shortly so I got a faulty CCFL.

This is where I decided to try and upgrade it to LED backlight, ordered this kit:
https://www.aliexpress.com/item/3280...100a4c4dlB7ZH9

And the obvious questions - where do i get the VIN (12v ?), ON/OFF and ADJ (adjustment) points (I think ground is not that difficult). Do I get them from the main board, inverter, power board ? Logic tells me on/off and adjustment should come from main (logic board) but tracing the connections they should pass through the power board and go to the inverter, does that make any sense ?

Any help is appreciated.

[Behemot]

Re: Dell 2007FPB teardown

The key value here is frequency. Low-frequency transformers (like the networks 50- or 60Hz) are huge and infficient for higher power passing through them. Switched-mode power supplies work usually within the 60-100 kHz range (but generaly can operate anywhere between 10 kHz and 10 MHz).

[knightace]

Re: Dell 2007FPB teardown

That's correct, ~230 V AC times square root of 2 equals to a bout 325 V. Where would DC appear from on the transformer? Since when can transformer transform direct current? A switch (usually transistor) cuts the DC into some kind of AC wave which can only than be transformed to higher or lower voltage.

The key value here is frequency. Low-frequency transformers (like the networks 50- or 60Hz) are huge and infficient for higher power passing through them. Switched-mode power supplies work usually within the 60-100 kHz range (but generaly can operate anywhere between 10 kHz and 10 MHz).

OH!! WHAT Was I Thinking... Sorry you are right ! about That AC Coming or going to Transformer, Transformer would never work on DC either for Primary or Secondary as it works with the Inductance Phenomenon.

Still, I need the Codes for the resistors, and Zener Diodes, Furthermore if you find out any Problem with the PCB, Solder Joints, or shorts, any help would be Greatly Appreciated !

And one thing more that's been messing up my mind, I asked that in my Previous post as well, why convert it into DC if we want to step down it later , why not step down AC Directly and then Convert it into dc?

[Behemot]

Re: Dell 2007FPB teardown

That's correct, ~230 V AC times square root of 2 equals to a bout 325 V. Where would DC appear from on the transformer? Since when can transformer transform direct current? A switch (usually transistor) cuts the DC into some kind of AC wave which can only than be transformed to higher or lower voltage.

The key value here is frequency. Low-frequency transformers (like the networks 50- or 60Hz) are huge and infficient for higher power passing through them. Switched-mode power supplies work usually within the 60-100 kHz range (but generaly can operate anywhere between 10 kHz and 10 MHz).

[knightace]

Re: Dell 2007FPB teardown

Its not Secondary, its Primary thats connected with the Transistor, Look I am confused here, because the Voltage that I read after being rectified into DC from 450V 180uf Cap is 328V dc. And then the Transformer shows above 1000V , How is it even possible ! . I dont know much but I will tell you what I understood about this Board. It takes 220V Mains AC , Rectifies it into DC, then converts it back to AC for the Transformer , steps down it to 19v and then rectifies it back again. If this is right what I said, then why convert it into DC if we want to step down it later , why not step down AC Directly and then Convert it into dc?