Dell 2408wfpb

[benco]

Re: Dell 2408wfpb

PSU : TP710 - 3,3V
TP707 - signal on=3,3V , off=0V
3,3V and signal go from the IC FLI30336-AC BGA
reball or new
https://www.aliexpress.com/premium/f...91&blanktest=0

[sebr]

Re: Dell 2408wfpb

Is the inverter of this display the same as the 2407 ?

[meangene]

Re: Dell 2408wfpb

Has this been resolved? I have the option to refurbish one of these monitors and it appears that it's exhibiting the same fault. I'd rather not have to buy replacement circuit-board modules...

[budm]

Re: Dell 2408wfpb

So your power supply is OK then since you are getting the 23V. Just start checking the voltage regulator on the main board next.

[knoxrebel]

Re: Dell 2408wfpb

Budm, they are the same boards.

[budm]

Re: Dell 2408wfpb

I like to see pictures of all the boards to see if they look anything like what I have here:
http://s807.photobucket.com/albums/y...P%20Rev%20A02/

[budm]

Re: Dell 2408wfpb

It looks like it works the same as the 2407 I just took apart, if he is getting the 23Vdc (the 2407 uses 19V always on power supply) then the power supply is working, the lower voltages are on the logic board and are done by the LDO regulator and buck converter regulators.
Start checking those voltages, it should have some 3.3V, 1.8V LDO on the logic board.

[jetadm123]

Re: Dell 2408wfpb

Having looked at budm's dissection of a dell 2407wfpb:

https://www.badcaps.net/forum/showthread.php?t=21042

Even though the boards are different, they apear to be made by the same company. Using the 2407 as a reference, it looks like the standby voltage is not 5v. The question now is your video card sending the PS/ON and BL/ON commands?

Have you tried measuring the voltages of the power/video board wiring harness when you press the on/off power button? Hopefully you will see one of the wires that's now reading 0v rise to ~3.5-5v

[knoxrebel]

Re: Dell 2408wfpb

The 4 components are mosfets Pn j598 ks 7

[knoxrebel]

Re: Dell 2408wfpb

23.1V for all. All boards were connected

#'s are 4h.oct02.a00/5E0CT02001 Power
4h.oct01.a02/5edcoct01001

[Rtech]

Re: Dell 2408wfpb

Just wondering if the 23V is the standby voltage and maybe there's some sort of 5V regulator on the video/logic board? Why else would they be running 23V to the logic/video board?

You may be correct,unfortunately I don't know a lot about this Model,so would be helpful,if we perhaps had some more input from someone who does ?

[jetadm123]

Re: Dell 2408wfpb

Just wondering if the 23V is the standby voltage and maybe there's some sort of 5V regulator on the video/logic board? Why else would they be running 23V to the logic/video board?

[Rtech]

Re: Dell 2408wfpb

I would concentrate on finding the 5v,This is normally the only voltage that is regulated,and the rest do tend to 'float' somewhat,so think the 23v for now is not a problem.

[selldoor]

Re: Dell 2408wfpb

Were the volatages taken with it all connected up?
In pic 4 down the right hand side there are the 4 bigger components with 2 and a half legs
bottom one might be Q30 - Can you read the part numbers on them(may be all the same)

[selldoor]

Re: Dell 2408wfpb

Were they exactly 23.00 or 23.99 or 23.01
I think were aiming for 24v so the rest of the decimals is important
Now to find the 5v

Have you got the board part numbers as requested

And what does the black writing say on the board edge

[knoxrebel]

Re: Dell 2408wfpb

Power going to inverter board
1 BL 23
2 BR 23
3 R 23
4 O 23
5 Y 23
6-10 Ground

Going to Video Board

Bl 0
NC 0
BR 23
R 0
O 23
Y 23
G 0
Blue 0
Black 0
Gray 0

[jetadm123]

Re: Dell 2408wfpb

I recommend you follow selldoor's suggestion in post #14 and measure the connector voltages. There's a 5V standby voltage that should be on at all times.

[knoxrebel]

Re: Dell 2408wfpb

Bad as in not working properly, like the focus on my point and shoot camera. Let me know if you need certain component numbers. Patiently waiting for those voltages.

[retiredcaps]

Re: Dell 2408wfpb

1st meter was an el cheapo that was bad.

Bad isn't the word I would use to describe it. Dangerous is more accurate when the readings are that far off.

[budm]

Re: Dell 2408wfpb

Always check them outside the circuits since it can have other components (resistors, capacitors, SEMI conductors) in parallel with the cap you are checking.