Dell 2407WFPb Monitor - Bad Cap

[Utarius]

Re: Dell 2407WFPb Monitor - Bad Cap

I posted here a couple of years ago, my monitor was fixed after a helpful man from Utah sold me a working power board at a reduced price if I sent my broken one back to him.

Fast forward a few years and the monitor still works, but it seems to be gradually getting darker/yellowing and there is also some uniformity issues cropping up where a patch just to the left of the centre of the screen is slightly darker than the rest.

Is this likely to be the inverter board for the backlight, or could it be the backlight bulbs themselves which are failing?

The monitor is about 10 years old now so it has certainly been a good buy.

[SkOrPn]

Re: Dell 2407WFPb Monitor - Bad Cap

Will these work for the large cap on the PSU? Are they even genuine Rubycons?

https://www.ebay.com/itm/141467570852

[SkOrPn]

Re: Dell 2407WFPb Monitor - Bad Cap

My video board had several very slightly bulged 220uF/35v and 220uF/25v caps. Anyway I decided to replace all 29 caps on the video board. This fixed my monitor .

Here's a list of the parts I used:

12 x 493-1864-ND CAP ALUM 220UF 20% 35V RADIAL $.30ea
11 x 493-1547-ND CAP ALUM 47UF 20% 25V RADIAL $.22ea
6 x 493-10411-1-ND CAP ALUM 10UF 20% 35V RADIAL $.55ea

NOTE: Some of the 220uF caps on my board were 35v and some were 25v. I decided to use all 35v.

I plan on doing the exact same thing too. Since the LEDs still come on, and I have at least 4 or 5 caps badly bulged on the video board I have to assume this board is at fault.

However, if anyone could point me to a common list of suspect components to replace on the PSU I would highly appreciate it. I might as well solder on higher quality pieces while I have this monitor apart, right?

[SkOrPn]

Re: Dell 2407WFPb Monitor - Bad Cap

Can you guys please make an step by step guide on how to replace the power board with an AC adapter?

Thank you very much!

I am interested in seeing this too. Seems like AdrianM tried to explain it, but his pics and explanation are too vague. My 2407WFPb still comes on, buttons work as usual, turns amber to green etc, but no display. It went from zero issues to suddenly no display after 11 years of trouble-free operation. Not sure if the PSU is bad or not, or if the inverter or ccfl's have gone bad. Although I am a good at soldering, I also see that this psu is only 12.99 brand new. You could replace it, get your monitor back up and running (assuming the psu is the problem) and then repair the old one as a backup.

I see no physical damage on my PSU, every component "appears" clean, but I know that means nothing. This makes me wonder though, especially since the front lights still work as usual. Hmmm, lol

[Mouse Trap]

Re: Dell 2407WFPb Monitor - Bad Cap

Hello electronics experts,

I've got classic 2 seconds to black problem with my Dell 2407WFPb: on turning on, it goes black after a very brief display of whatever supposed to be on the screen; power button stays green.

There's no audible hiss or buzz, PSU and inverter boards look absolutely fine - no blown caps, no leaks, nothing visibly wrong but one thing: the tin cover that goes over inverter board has six rusty spots inside, just where the lamps are plugged in. Not sure if it's relevant -- photo attached.

Ok no electronic expert but this is the same problem my 2407WFP had i.e. every time I switched it on I got video for 1-2 seconds. Like you I replaced all the caps on the PSU but I also replaced the 120uF/450v cap. This cap on my PSU looked bad and I feel fortunate it didn't take out the PSU. Before I found this thread I had no plans to recap the PSU. I was looking at the top of the caps not the bottom so thank you for this thread!

My video board had several very slightly bulged 220uF/35v and 220uF/25v caps. Further more when I removed this board from the monitor I noticed the back of it had a yellowish stain around the mounting points. After removing all the caps on this board I'm wondering if this stain wasn't from leaked dielectric. Maybe I'm wrong but I found the same yellow stuff under some of the caps. Anyway I decided to replace all 29 caps on the video board. This fixed my monitor .

Here's a list of the parts I used:

12 x 493-1864-ND CAP ALUM 220UF 20% 35V RADIAL $.30ea
11 x 493-1547-ND CAP ALUM 47UF 20% 25V RADIAL $.22ea
6 x 493-10411-1-ND CAP ALUM 10UF 20% 35V RADIAL $.55ea

NOTE: Some of the 220uF caps on my board were 35v and some were 25v. I decided to use all 35v.

[rickvanderzwet]

Re: Dell 2407WFPb Monitor - Bad Cap

I desided the broken 2407WFPb SMPS would be a great project to fix, since the great amount of information found at this forum and it's well documented PCB (thanks Dell!). It started as an small one-evening hobby project and turned out to be an 6-months on-waiting-for-parts-off experience. It has been an joyful experience however, which I am now typing looking at a fixed monitor. I would like to thanks all for the information provided.

Reading shortlist:
A special thanks to the following posts for their usefulness and/or high entertainment factor:

• Feeding logic board by external PSU to test by AdrianM
• The Light Bulb in serie power usage monitoring and limiting by PailBill
• Fault finding by Chris Colborne shared by endor
• MOSFET testing by budm
• Beep testing by Tyan
• Schematic diagram by supertox
• Walktrough by elvena

The fix:
Replaced both ICs together with the 'usual' suspects, making it the listing of:

• IC601 NCP1200D60
• IC651 L6561D
• ZD601 15V 0.5W Zener diode
• C605 RUBYCON KXW 120uf 450v 120mfd Capacitor
• F601 4A 250V Quick Fast Blow Glass Fuses Fuze
• R669 0.22 ohm 0R22 2Watt Metal Film Resistors 2W Resistor 1% #0680
• Q651 2SK3502
• Q654 2N3906S

Ordered them all on ebay.com, it took me roughly 4-6 weeks for items to arrive (based in The Netherlands):

• 100pairs OR 200PCS Transistor SOT-23 ( SMD ) 2N3904/2N3906 MMBT3904/MMBT3906 = 1.40
• 100PCS 4A 250V Quick Fast Blow Glass Fuses Fuze 5mmx20mm = 2.99
• 10pcs Panel Mount PCB Fuse Holder Case w Cover 5x20mm = 1.85
• 5PCS L6561D L6561 ST POWER FACTOR CORRECTOR SOP-8 SOP8 SMD TOP = 1.23
• 10pcs 2SK3502 K3502 N CHANNEL SILICON POWER MOSET TO-220 = 6.58
• 50PCS 0.22 ohm 0R22 2Watt Metal Film Resistors 2W Resistor 1% #0680 = 2.50
• 2pcs RUBYCON KXW 120uf 450v 120mfd Capacitor -40~105℃ 18*40mm = 6.99
• 5PCS 200D6 NCP1200D60 SOP8 IC = 3.62
• 1280Pcs 0805 SMD 64 Values 5% SMT Resistor Chips Assortment Kit 0ohm-10Mohm = 2.89
• 280Pcs 3V-39V ZMM SMD Zener Diode LL34 1206 14 Values 20pcs each Assortment kit = 3.15
• 100pairs OR 200PCS Transistor SOT-23 ( SMD ) 2N3904/2N3906 MMBT3904/MMBT3906 = 1.40

The total costs of my project was roughly 35 EUR/USD. I ordered multiple quantenties allowing me to kill a few and more importantly use them as reference measurements counterparts to find out if my board component was still working. If somebody based in The Netherlands, is looking for the components, feel free to send me a message to get my remaining stock sent.

Lessons learned:

• Reading the whole thread (multiple times) proved to be usefull and nessasary, yet an lengthy process, I hope the post will be a nice summery to success.
  
• If you are unsure with the logic-board and/or inverter board is still working, use the quick hack of AdrianM to first verify they are still working.
  
• Mind your safety, it are high voltages after all, use common sense and tricks like the 'bulb' test to limit the amount of fuses you have to replace. Always measure voltage over C605 ensuring it has dropped to a safe level, before handling the board.
  
• SMD soldering is a 'art', if possible use an SMD soldering station, a cheap one in the range of 100-150 EUR will do the trick over here, and/or go to your local MakerSpace to get help with soldering.
  
• Be careful when soldering, it is very easy to make solderjoints, re-test all new components before powering on. Also verify the the pads of the ICs are not floating. Put one test probe on the leg of the IC (near the black casing, not on the solder) and the other probe on the component it is connected to, use the famous 'beep test' to verify the path is made successfully.
  
• Test the board without the inverter board and logic-board attached. If successful attach the logic-board, you will now see output of by the LED of the power-button. The board itself will then consume roundabout 20W (easy to use with the light-bulb test). Mine was flicking and the board was making 'clicking sounds' after repair, this was fixed by soldering an floating IC leg, and cleaning the board with isopropanol one extra time to remove left-over soldering paste 'mess'.

Bonus:
Two of my buttons was broken (not responding any-more) aka the Menu & Plus button. To fix this; a) expose the button PCB b) for the affected tactile button peeled off the plastic of the button c) rotated the metal disk inside 45 degrees and d) put an piece of tape on it to hold it in place. Use the multimeter (resistor mode) to verify the pads are working fine again. Note there is a protective plastic cover of the back of the PCB, such that you need to apply some pressure (or remove the plastic) for the test pins to be reachable again.

[Bismar]

Re: Dell 2407WFPb Monitor - Bad Cap

I have a 2405 monitor with a 48.L1E02.A03 power board. Does anyone know if the 4H.L2K02.A01 E1 boards for the 2407 monitor are a drop in replacement?

I ask this as a quick BOM of likely failure components indicate that its cheaper to purchase the 4H.L2K02.A01 E1 board off ebay.

[jmb]

Re: Dell 2407WFPb Monitor - Bad Cap

I take no credit for below - all cred goes to "Chris Colborne", can't recall where i found it.. fixya or something?

http://www.fixya.com/support/t152933...uff_smoke_dead in follow-up comments on his initial answer.

[Pierre95]

Re: Dell 2407WFPb Monitor - Bad Cap

Hello,

I also have a no powering 2407WFP. As for many, leakage can be seen on the + PIN of C605, and a damaged R670. I also have a completely destroyed IC 651 (L6561 D) + R669.

Don't know what caused IC 651 destruction, maybe a sudden voltage increase at the CS PIN which may also explain R670 and R669 destruction due to C605 failure.

I have many LCD power boards, but none has a L6561D, each use a different IC for power factor correction. And there seems not to be PIN to PIN equivalency.

Hope that after replacing all 4 parts, it will work again.

[Vitec]

Re: Dell 2407WFPb Monitor - Bad Cap

Hello!

My 2407 also gone these Days but its not only the screen is black or power dont turn on .
I was working normal but then this little "boom" and the complete Power of the electric curcuit was gone. After checking the fuse box the fi switch and the circuit switch where off.
So for now i am not able to connect the Power Cable from the Monitor to an electric Curcit without activating the saving switch in the fuse box.

So first i am happy to found this Forum because i think this is exactly was i was searching for . i dont know anything about electronic but know someone if something have to be fixed.
So first thing i found after some research in that thread is that R 670 is definitly gone. For the C605 i am not sure its a little bit corrosion but not that much as on other pics in this thread.
Also theres an component called BD601 that have some white "fluid" clue left and right that is not that hard one so pherhabs this is also damaged.

I also have made an Pic of the Board with the Connections because there are also capacitors that seemed to be damaged of what i read so far on the internet. They are lightly "arched" (dont know if this is the right word) on the top .
All other Capacitors seems to have no damage on the sides or on Top.

So first because theres no measurement possible because no connection to the electronic curcuit possible should i try to change R670 and C605 first and then if that works check all other components .Or is a measurement always working (as i said i know nothing about electronics) so i have to check my friend first so he can test everything ?

Or do you think this Monitor is really Dead because the save electronic switch turn on ?

PS.: I am from Austria so i dont know if some replacement are working in Europe because we have a different Power Supply System.

[gheoss]

Re: Dell 2407WFPb Monitor - Bad Cap

Can you guys please make an step by step guide on how to replace the power board with an AC adapter?

Thank you very much!

[Schorsch87]

Re: Dell 2407WFPb Monitor - Bad Cap

Hey guys,

I found the faulty component. IC651 was defective. Even if it is not shorted pin8 to pin4 it can by faulty.
So I changed R603, IC651 and IC601 just in case.

Thank you guys.

kind regards and a happy new year

[Schorsch87]

Re: Dell 2407WFPb Monitor - Bad Cap

Schorsch87, take a look at the circuit diagram, post 387, page 20. The only way R603 would get fried is if the PWM module (IC601) has failed and became shorted pin 8 to pin 4. This has been occasionally reported here (e.g. post 384). If you are changing IC601, might as well change the other IC (651, the PFC). And make sure you have good resistance across Q651 (measure from D down to S).

But I do not measure any shortcut on IC601 pins. And on IC651 I also do not measure shortcuts or the suggested 42Ohms. It's all in the kOhms range or above.
But to be sure I ordered IC601 and will swap that one.

C605 doesn't show any damage also Q651 doesn't measure a short. If it were shorted I can't measure the 310V over C605, am I right?

Regards

[pkanar]

Re: Dell 2407WFPb Monitor - Bad Cap

balkeep,

Your failure mode is similar to most other's here. The corrosion of C605 terminal causes it to disconnect. It is this disconnection that causes a cascading failure of circuit components. You managed to achieve that with a bad solder joint.

R670 is 0.22 Ohm, 1 Watt.

Whether IC651 can have 42 Ohms between some pins, I can't recall; it's possible. Check your Q651 with an ohmmeter, D to S. If it's short, assume that both IC's are toast as well.

[pkanar]

Re: Dell 2407WFPb Monitor - Bad Cap

Schorsch87, take a look at the circuit diagram, post 387, page 20. The only way R603 would get fried is if the PWM module (IC601) has failed and became shorted pin 8 to pin 4. This has been occasionally reported here (e.g. post 384). If you are changing IC601, might as well change the other IC (651, the PFC). And make sure you have good resistance across Q651 (measure from D down to S).

[Schorsch87]

Re: Dell 2407WFPb Monitor - Bad Cap

Hey Guys,

nobody wants to help me?

So I did the audiojack mod to verify the display and the other boards are working. And they do!

So the problem is really the power board. Does anybody have an idea what to check next. 19V are not present!

Regards

[Schorsch87]

Re: Dell 2407WFPb Monitor - Bad Cap

Hey guys,

I have need your help. My 2407 has gone. So I turned the problem down to the power supply. I measured a bit and found out that I have not the common problem with the C605 and the other components.

Only R603 was obviously burnt and I changed it with a working on. But the power supply doesn't give me the 19V.
But I have the 310V over C605 (I'm from Germany).

So now it's your turn, because I do not have any idea what to do next.

Regards

[balkeep]

Re: Dell 2407WFPb Monitor - Bad Cap

I have quite a funny story to tell.

I've replaced C605 and other caps on PSU board after 6 years of use in advance to avoid any damage, used nippon cap for a big one and thought I was safe.

Imagine my surprice when like a month after that I heard POP sound and monitor went dead. I disassembled it and saw that 1 leg of C605 was dis-soldered for w/e reason (probably that's on me, bad soldering?). Cap itself looks totally okay. Examining the board showed clear signs of Q651 burnt, also main fuse's dead as well. Diodes that are close to Q651 seem alright, although I'm not quite sure about IC651, there is like 42 Oms resistance between some of its legs. I then got monitor working using trick described in post #155 with an old brick PSU from something (printer?) of HP origin, but it's a bit weak I guess, it's 18.5V, 3.5A, 65W. I run brightness on 15% for now, but I hope to get internal psu repaired.

Can some1 tell me if IC651 having 42 Oms resistance is actually okay?
Can a resistor be burnt with no visual signs of that? What resistance R670 is supposed to have?

I actually don't know much about electronics, so I'm like lost in a forest and need a guide =P

[olek]

Re: Dell 2407WFPb Monitor - Bad Cap

After about 8 years my 2407 wouldn't turn on. Found this post and identified the following damaged components:

• C605 (corroded pin)
• F601 (high resistance)
• Q651 (low resistance between all pins)
• BD601 (low resistance between pins)

Replaced with the following parts:

• C605 Panasonic EET-ED2W121BA
• F601 ST Micro STP10NK60ZFP
• Q651 Littlefuse 0215004.MXESPP
• BD601 Rectron RS405M

Plugged it in and it worked! Thanks to everyone in this thread.

[KARTEK-PRO]

Re: Dell 2407WFPb Monitor - Bad Cap

FDAI is actually FOAI,

The weblink is:
http://www.chinafoai.com/eproducts.htm

and the cap details for the CD112A series can found at:
http://www.chinafoai.com/ep12.htm

I found it thru the same link provided by 'toasty'

look in 'F other'

hope it helps, if i'm not too late..

Alright so this is what I have come up with for the power board. This is as far as I can go for today. I cannot find the FDAI brand anywhere and I can't pull the specs from ELITE's site from any browser. Hopefully Elite's site will work better tomorrow. Has anyone heard of the FDAI brand?

EDIT: I took toasty's link from earlier () and altered the link to reflect the different series ( and ) and it worked!! All I'm missing to complete the power board is to figure out the FDAI mystery.

FDAI (I think)
50V 47uF
U32 105C
CD112A
Picture available if necessary
Measurements not available*

Jamicon
100V 1uF
TK P105C
624C2(M)
Picture available if necessary
Measurements not available*

Elite
35V 470uF
EJ(M) 105C
(C)0616 FET
Picture available if necessary
Measurements not available*

Elite
25V 220uF
ES(M) 105C
(C)0620 FET
Picture available if necessary
Measurements not available*

Elite
450V 120uF
PW(M) 105C
(C)0623 FET
Picture available if necessary
Measurements not available*


*I felt confident with this process and I didnt measure the caps. I now know that it was a foolish mistake on my part but it was partly because of the trouble im going through to get the measurements. My ruler wasnt made for this, its long and bulky and the measurements don't begin at the tip of the ruler. What are you guys using to measure?