Dell 2407wpf no source picture.

[bakke33]

Hello,

I have tried to search this issue, to no avail.

The dell 2407wpf gets a picture when I turn it on and displays the OSD.

I can't get any source video from any of the inputs.
I have tried with DVI,VGA,RCA,S-video.
DVI just goes to power save, rca and svideo flashes the connection icon(like it doesn't get a sync signal).

What I can see on the logic board is that the different inputs goes to different chipsets. That to me indicates that the fault must lie further in.
Where they join together. Altough the OSD works.
Anyway I haven't found schematic for the logic board only the power board.
So I can't check where the issue might be before I begin to randomly check voltages from the input sources.

Anyone here have a good clue what this might be and how to proceed the repair ?

Regards B

[momaka]

Re: Dell 2407wpf no source picture.

Well, before you go poking in there trying to find out what the issue is, first rule out the simple things - that is, make sure all electrolytic capacitors on the power board and the logic board are fine. If they are not a quality Japanese brand, it's probably a good idea to pull them out of the board and test their ESR, as they can be bad without bulging at all. Bad caps can cause all sorts of random problems like this. On that note, the small capacitors filtering the linear regulators on the logic board will often go bad without any visual signs, so those are even more critical to check.

Once we know the caps are okay, then we can go from there to try and figure out the problem (if it persists).

[bakke33]

Re: Dell 2407wpf no source picture.

Ok thanks.
I'll get back when I have exchanged/measured the esr of the caps.