Dell 2407WFPb Monitor - Bad Cap

[terry]

Re: Dell 2407WFPb Monitor - Bad Cap

The big cap is the correct way round, I have checked F701 and that's fine. I have had a good look at the board and I can not see any more fuses.

I have just uploaded some full size pictures to my website, if you want to have a look at them that would be great. www.linfotech.co.uk/psu1.jpg www.linfotech.co.uk/psu2.jpg

Thanks

Terry

[selldoor]

Re: Dell 2407WFPb Monitor - Bad Cap

Quick questions - I have to go out
The Big cap IS the right way round?
There is a small yellow torpedo fuse F701 just to the left of the big cap - does that test ok. Resistance and voltage both sides with respect to ground screw.

I think on the Main Board - all these posts and I cant spot a single decent picture of the whole board- near one of the connectors there may be a small black rectangular fuse with a 20 or 2.0
on it - if you can find it can you test it as well.

[terry]

Re: Dell 2407WFPb Monitor - Bad Cap

Here are some pictures of the power board, hope they help. The large green cap is fine, the marks are where it was glued the other way up on the power board I removed it from.

Terry

[selldoor]

Re: Dell 2407WFPb Monitor dead psu

Can anyone help , I was given a Dell 2407 monitor with a faulty power supply model numer 4H.L2K02.A01
The 400v cap was leaking, R670 blown, Q651 (2sk3502) blown and the main fuse has blown.

I have replaced the 400V cap, R670, Q651 (2sk3502) and the main fuse, No bang but still no power out.
I then replaced the IC651 (L6561D) but still no power out.

I have the 300v DC @ L610 TO R605, 166V from R605 to R604 and only 19v from R604 to C614, after that @ T601 no volts.

Can you post a good clear picture of your power supply board

[jasonkoelling]

Re: Dell 2407WFPb Monitor - Bad Cap

Anyone know where to get a replacement or alternate board for the 2407? for under $50.
Iv found a few online but they are all over $50 and it just isnt work that much to me.

4h.l2k02.a01

5E.L2K02.001

4H.L2K02.A11


https://www.myallparts.com/-p-188.html

[terry]

Re: Dell 2407WFPb Monitor dead psu

Can anyone help , I was given a Dell 2407 monitor with a faulty power supply model numer 4H.L2K02.A01
The 400v cap was leaking, R670 blown, Q651 (2sk3502) blown and the main fuse has blown.

I have replaced the 400V cap, R670, Q651 (2sk3502) and the main fuse, No bang but still no power out.
I then replaced the IC651 (L6561D) but still no power out.

I have the 300v DC @ L610 TO R605, 166V from R605 to R604 and only 19v from R604 to C614, after that @ T601 no volts.

[jasonkoelling]

Re: Dell 2407WFPb Monitor - Bad Cap

Thanks for the reply. that chip , that is chipped does not have any writing or markings on it. I have seen the chip intact in other pictures and it is just black. Going to be hard to find. im almost to the point I would rather just replace the whole power board then to spend time tracking down what cap is bad. I replaced the only 2 that had corrosion on them.. the big 240v and that smaller that looks out of place. I was given this monitor broken for free so all i have invested in it is time and about $10-$15 in caps. Id be willing to sell it cheap if someone wants to take on the project as I dont have the time/know how to troubleshoot boards beyond replacing caps.

[selldoor]

Re: Dell 2407WFPb Monitor - Bad Cap

You only replaced 1 cap in a row? All the caps are the same age same size in the same place - why would you think only one is bad?
Anyway on to the chip - it looks burnt but picture is not close enough to tell for sure.
If you are sure its gone then you have nothing to lose in trying to replace it?
Some mebers just snip the legs or dremmel them then remove the rest of the legs using tweezers - once you only have legs to unsolder it becomes a lot easier.
Is there a part number on the chip and also take note which way around it is on the board before you remove it.
Some members will not look at pictures hosted off site. you should post them like this
We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back (in the same orientation) and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

Please do not post inline and offsite as they slow down the loading of pages.

Examples of what is needed

https://www.badcaps.net/forum/attach...7&d=1280167246

https://www.badcaps.net/forum/attach...6&d=1280167246

https://www.badcaps.net/forum/attach...4&d=1280167246

[jasonkoelling]

Re: Dell 2407WFPb Monitor - Bad Cap

I have a 2407WFPb with what I believe has a bad power supply. I bought a cap kit to try and repair the power board and after further investigation I found some burnt area's on the bottom side of the board. im confortable replacing caps but I think replacing anything else is a little over my head. any feedback would be great .

http://s34.photobucket.com/user/jaso...ell%202407WFPb

[hartklep]

Re: Dell 2407WFPb Monitor - Bad Cap

Yeah, I have had a look at the components and it "looks" fine - so I am kinda hoping someone will be able to answer my 3 questions

I want to find out the resistance between the 3 legs of Q651 when it is on the board. I get a very small resistance between the 3 legs (about 115 ohm)

Also what is the resistance across the Zener diode ZD601 on the board? Again, I get a small resistance.

Would a 2W rating be sufficient for Resistor R670 (0.23 ohm) - this is the only other component that has obvious damage

Thanks again

You need an transistortester to check Q651 and the ZD601
When you R670 is damage there is more damage.

[leapius]

Re: Dell 2407WFPb Monitor - Bad Cap

I thought I might hijack this thread to ask about my 2407 problem:

The monitor is completely functional in every way apart from after about 10 seconds from start up it will suddenly flicker from normal to full brightness and stay that way until it is turned off. The brightness setting has no effect once it goes into this full brightness mode.

I originally changed the inverter to solve a backlight problem as illustrated in this thread:
https://www.badcaps.net/forum/showthread.php?t=22549

Now I'm wondering if there is something wrong with my replacement or something else? Any suggestions?

Thanks

[sirzur]

Re: Dell 2407WFPb Monitor - Bad Cap

Yeah, I have had a look at the components and it "looks" fine - so I am kinda hoping someone will be able to answer my 3 questions

I want to find out the resistance between the 3 legs of Q651 when it is on the board. I get a very small resistance between the 3 legs (about 115 ohm)

Also what is the resistance across the Zener diode ZD601 on the board? Again, I get a small resistance.

Would a 2W rating be sufficient for Resistor R670 (0.23 ohm) - this is the only other component that has obvious damage

Thanks again

[hartklep]

Re: Dell 2407WFPb Monitor - Bad Cap

I had the same problem with rust on the capacitor.
When i desoldeer the Cap the leg fel off.
With the Q651 i had the same problem.
The best thing you can do is to replace the part from the list
that mr MPX post.
I had also an defective bridge rectifier
By Farnel it only cost you abaut 35 euro

[jetadm123]

Re: Dell 2407WFPb Monitor - Bad Cap

I think you're in the 1% that needs to replace the large 450V cap. Others have also reported seeing that large cap leaking.

[sirzur]

Re: Dell 2407WFPb Monitor - Bad Cap

For the board I am looking at, there is no question that the large cap is gone. One of the legs has rust like material at the junction with the capacitor

[RethoricalCheese]

Re: Dell 2407WFPb Monitor - Bad Cap

If the large cap seems fine, it 99% of the time is fine so there is no need to change it. Atleast I have never had to change it, fixing about 200 LCD-s (except one that was hit by a lightning)

[sirzur]

Re: Dell 2407WFPb Monitor - Bad Cap

Also trying to troubleshoot this PSU board.

Can someone who has a spare of this board (not in a monitor) do some measurement?

I want to find out the resistance between the 3 legs of Q651 when it is on the board. I get a very small resistance between the 3 legs (about 115 ohm)

Also what is the resistance across the Zener diode ZD601 on the board? Again, I get a small resistance.

Second last question - would a 2W rating be sufficient for Resistor R670 (0.23 ohm)?. I note in the Farnell part number that the rating is 3W

I am thinking of sourcing everything from ebay - found some Nippon KXJ 120 uF, 450V capacitors. Anybody has experience with these? I know the general consensus is to use Panasonic or Rubycon caps.

[budm]

Re: Dell 2407WFPb Monitor - Bad Cap

19~20V will be fine since the voltage will get step-down to run the low voltage circuits, the 19~20 will be used directly for the inverter circuits which is not critical.
Higher amp rating will make it run cooler.
Per Dell, the max power is 110W.
http://support.dell.com/support/edoc...P/en/about.htm
As you can see in my picture, I measure it to be about 19V.
http://s807.photobucket.com/albums/y...t=DSC00067.jpg

@engrken, please see the spec. 73w power supply is too low.

[deadvirusllc]

Re: Dell 2407WFPb Monitor - Bad Cap

Hi there...
Since my WFP2407 stopped working yesterday and I have no service-tag (and the dealer I bought my display from is not doing anything regarding to PC-stuff anymore) I descided to open up my Display.

It was the F1 fuse that was broken (measured several M-Ohm inside the circuit over the fuse). So I searched through my boxes with stuff and found some old glass-fuses rated 2.5A. I did assume that the 2.0 on the fuse stands for 2.0A so 2.5A was close enough for me to test.

The Fuse with some wires soldered to it:


The replacement Fuse:


After the usual seconds of doubt I plugged in the device and got the DELL-Logo, it was alive again! Nice...

Since I cannot get my hands on a 2.0A SMD-Fuse currently I decided to just clean up the stuff I did a bit and repack my Display until I get a nicer fuse.

A bit nicer:


I think I will try to get my hands on
BOURNS - SF-1206S200-2 - FUSE, SMD, 1206, 2A
since the dimension fits, it is a slow fuse and rated 2.0A. But the minimum order value at Farnell (and resellers for private persons) keeps me off from testing it right now.

Maybe someone gets here via google (just like me) and gets motivated by the pictures

Regards

That fuse was my problem! I checked every fuse and didnt know that one was hiding there! Two years later and that post solved my problem.

[deadvirusllc]

Re: Dell 2407WFPb Monitor - Bad Cap

Ill be damned! Was gonna toss this thing after replacing all the other pcbs and fuses. Didnt know that fuse was there.