Dell 2408WFPb / 2408WFP - No Power

[luke9511]

hey everyone, is there any place to get a cap kit for the dell 2408wfpb?

[Thermaltake]

Hmm, not similar at all, mine wasn't turning On at all. And I noticed on the bottom of the caps(few of them) they leaked, when looking from the top they all look fine.


Is it just mine 2408W monitor that is extremely hot on the top of when it's on for like 2-3 hours or that's normal ?

[Aezakmi]

Hi,

I have similar problem that I descripted here..

Shortly: power led is green, backlight is working but screen is blank with no OSD.
Today I heated up the two heatsink with hairdryer, plug the cord, pres.s power button and something appeard on the screen. More like some artifacts, but when I pressed input button, blue rectangle from OSD showed up in the corner. It was without port icon and port name.

I consider to buy hot air station to reheat these two chips.

Do you think is this issue still worth of affort?

[Thermaltake]

Monitor fixed. It was caps on PSU, I replaced them all with quality ones rubycon/nichicon, and one mosfet died probably because of one really dead(burned) capacitor.

[Thermaltake]

I will replace them all, I already ordered rubycon/nichicon low esr caps, don't know why they didn't put low esr on power supply... That leaked one is lelon they are reeealy garbage caps just like capxon, and hopefully after recap it will work. I really didn't expect dead monitor after just going with brush a little to clean dust of everything (monitor was never opened) I didn't even disconnect any of boards or anything like that and when I assemble it completely dead. First I was thinking of that flex cable for buttons, but it's not garbage and can't damage just like that I was really carefully when I disassemble the monitor didn't stretch anything or force anything. So my only suspect was that cap and one that is near I think same values, it got funny color just like this one but it didn't leak.

[nabla666]

Yes, it could be.
The capacitor costs nearly nothing ( 5 for 1 € )
You should try to change it ( or make it done by someone who could

[Thermaltake]

EDIT:

Now when I was looking on the downside of caps I found that on PSU section one cap leaked, could only that cap be the cause of monitor not to power on ?

[Thermaltake]

Hi, have same monitor it was working normally until I open it to clean with brush, nothing special and it was a bit dusty from inside. No bad caps or any burns, and when I assemble it it won't turn On at all, no green light no anything...Not sure if problem is in flex cable that connects front buttons or something else...Don't have multimeter to measure.

[pylorak]

Re: Dell 2408WFPb / 2408WFP - No Power

Just this week I had the same problem like some users in the beginning of the thread: My Dell 2408WFP could not turn on, the power LED was slowly blinking. Looked like a restart loop. When disassembled, I too noticed the PSU board clicking, the sound coming from somewhere near the right side of the board.

All caps looked good to the naked eye (no bulging, no discoloration, no corrosion or any other noticeable irregularity). So first I replaced only the AK431AZ, but after that the issue was still present. Then I replaced C606 and C611, as well as the large 120uF cap. The monitor is now working without a hiccup

Big thanks to this forum and its users!

[NEO_Gai]

Re: Dell 2408WFPb / 2408WFP - No Power

My 2408 seems to have issues with overheating. Its been running fine, but now that summer weather is kicking in, it seems like it gets too hot and then shuts off.

I'm assuming its heat, because with a temperature gun aimed at the front of the screen immediately after it blanks out, it's reading about 108 at the top-center.

The power LED stays green, but the screen goes completely blank. I can try unplugging and plugging it back in, but results differ. Sometimes the power LED flickers on as I plug it in, but then stays off. Other times, the power LED turns on, but still a blank screen.

If I let it cool down while unplugged, it seems to power back on again.

I'm not electronically inclined, trying to learn though.

[ddfix]

Re: Dell 2408WFPb / 2408WFP - No Power

My ±13 year old dell suffers the same problem - power on and lights up but just white blank screen with limited menu button control. Guess that's pretty common issue with these dell 2408 monitors...Thank you all for the tips and fixes.

[sam_sam_sam]

Re: Dell 2408WFPb / 2408WFP - No Power

I bought another 2408WFPb with a working power supply, put the two power supply boards side-by-side, focused some resistance checks on the feedback/isolator area and found differences associated w/ IC701. Out of circuit, the KA431 shunt regulator did not behave right per simple VOM checks. Swapped in a replacement KA431, and voila!

Yea I know I am responding to a very old post but when I read this I had to respond to the comment

I have used this method before but I recently saw a YouTube video where this woman use the diode test on a multi meter and it does a better job according to her but I have not tried this yet my self but I am going to try it when I have something to troubleshoot again that I have more than one of the exact same units

[shumer]

Re: Dell 2408WFPb / 2408WFP - No Power

Thanks everyone! this forum is the best! After reading all 5 pages, I fixed my monitor!

[wertert]

Re: Dell 2408WFPb / 2408WFP - No Power

The hexagonal screw from VGA and DVI may probably not have to be unscrewed.
(You can unscrew all by precaution)

But there at least is one screw on the HDMI port and 2 others on the cinch sounds block .
Please look at this photo :
https://www.befr.ebay.be/itm/Dell-24...-/123799118769

And if it doesn't move may be there reamains at least one screw...

Update - thanks again to nabla666 for the advice.

All worked out ok. Had to swap the main board ( 2 large heat syncs ) and the first smaller power board. I think I damaged that earlier. New combo screen works well. I also have a few spare parts ;-)

[nabla666]

Re: Dell 2408WFPb / 2408WFP - No Power

The hexagonal screw from VGA and DVI may probably not have to be unscrewed.
(You can unscrew all by precaution)

But there at least is one screw on the HDMI port and 2 others on the cinch sounds block .
Please look at this photo :
https://www.befr.ebay.be/itm/Dell-24...-/123799118769

And if it doesn't move may be there reamains at least one screw...

[wertert]

Re: Dell 2408WFPb / 2408WFP - No Power

You have two small PCB on the left ( they are the power supply ) and a bigger PCB which is the main "motherboard".
The first power supply in which you plug the electricity is an isolation transformer and the second one is the AC->DC transformer.
I would just put the working motherboard you just bought on your old monitor, that the easiest and the only solution.

Personnaly I made the same move : I bought a 2048 with a defective LCD panel for 10 € but it was at least displaying something.
I put the motherboard on my 2048 and at first it was working.
( Before that I could warm the old motherboard with a dryer and it would work ! )

The only problem after the exchange is that the monitor would switch off after a while.
It was probably a power heating problem with the power supply I fixed not as good as necessary.

As I was not having the use of the 2048 anymore, I gave the two to a friend who swapped the power supply too and voila, it works again !

Thanks for the advice. I'm trying to take it slow and no break anything. Removing the old motherboard from the dead monitor. This is the board with the 2 large heat syncs on it. Removed 4 flat head screws holding it down. Doesn't want to budge. Do I need to remove the hexagonal bolts securing DVI & VGA sockets to the socket plate? ie that also secure the plug/lead.

[nabla666]

Re: Dell 2408WFPb / 2408WFP - No Power

You have two small PCB on the left ( they are the power supply ) and a bigger PCB which is the main "motherboard".
The first power supply in which you plug the electricity is an isolation transformer and the second one is the AC->DC transformer.
I would just put the working motherboard you just bought on your old monitor, that the easiest and the only solution.

Personnaly I made the same move : I bought a 2048 with a defective LCD panel for 10 € but it was at least displaying something.
I put the motherboard on my 2048 and at first it was working.
( Before that I could warm the old motherboard with a dryer and it would work ! )

The only problem after the exchange is that the monitor would switch off after a while.
It was probably a power heating problem with the power supply I fixed not as good as necessary.

As I was not having the use of the 2048 anymore, I gave the two to a friend who swapped the power supply too and voila, it works again !

[wertert]

Dell 2408WFPb / 2408WFP x 2

Hi All

Amazing that this thread from 2011? is still helping people ! I had one of these monitors which died sometime last year. Couldn't throw it away.

It's now working again thanks to the hair dryer trick ! Brilliant.

So options-wise...

- Replace the mainboard ? I've found one on ebay for £40.00 ish which seems ok.

- Never switch it off ? i.e will standby heat be enough to keep it from dying again ?

Anything I missed ?

Great result and thanks to all again

wert

Hi All

Update for you. Had to move rooms at home during lockdown so my problem monitor was switched off and unplugged. It got cold and now will not power up even if I heat the same area as before. I also managed to short the control ribbon cable against the power supply ( like the last poster ).

Not wanting to give up I've purchased another monitor for £20.00. Powers up ok but it's got the very common black vertical line 2 inches from the left hand edge.

So the question is. Can I combine these 2 monitors ( 1 dead / 1 blackline ) and produce a working one with zero defects ?

Main issue I have is i'm not sure what the various boards do inside the casing. Do you think the best bet is to swap the LCD panel over ?

Thanks again

Wert

[nabla666]

Re: Dell 2408WFPb / 2408WFP - No Power

My power card(s) were not functionning...
I made several mistake during the repair ( I tested with the command ribbon under the power card by error and it shorted... )
I had an extra one, so not too much bad.
So I changed the fuse, a varistor and and a diode.
And it still does not power up untill I blow heat on the motherboard....

I did not want to try the heating fix so I buy another broken 2408 for 10 €
The display panel is out of order on this one but the other parts seems to work.
I took the motherboard to put on my 2408 and it worked....at the beginning....

The monitor does power up and works (!) but after a certain amount of time it seems to shut off.
The monitor seems to heat a lot...not sure if it is normal...
I could try to exchange my repaired power cards with the others to see it if change anything but as I have no more usage for this monitor, I give up.
I gave it to a friend.(with a Samsung Syncmaster 244 T still working from 2006 !!!, it was my dual monitor at works but since my employer provided me 2 Aoc 4k 27"

[ramiltor]

Re: Dell 2408WFPb / 2408WFP - No Power

Did not expected that. I had no power, ordered new power supply, still no power. No power LED at all, 23.5V on some wires, fuses good. Heated up big chip on main board with hair dryer, reconnected cord and power is back.