Re: Dell 2407WFPb Monitor - Bad Cap

We have a Winner:
My 2407WFP is working again.

The for the cap C626 i used 1nF, Farnell 1856532,
seems to work fine.

Still working on the Schematics, have it but need to draw them better.
Will post when ready.

Thank you for you help!

Re: Dell 2407WFPb Monitor - Bad Cap

I did not find that russian site so far - thanks!
On my board, C628 is a fair bit 'higher' (or thicker) than (what remained of) c626.
Anyway i measured C628 - it's 1uF.

R669 and C626 form an RC-Lowpass for the current-feedback,
currently i don't know the switching-frequency, but 1microfarad seems to be to much:
R669 is 1k, so the filter has a Frequency of 195Hz, which i think is to low, since the switching-frequency is probably somewhere around 10kHz.
I think i will try with ~1-10nF (159kHz - 15.9kHz)....

Re: Dell 2407WFPb Monitor - Bad Cap

Yes, ok.
No, unfortunately there are no markings.
It is a standard SMD case, probably 0805 size.
Voltage would be verry low, this cap goes from Pin 4 of the L6561 to Ground.
Pin 4 is the current-feedback-voltage, measured by the famous R670, which is 0.22Ohms.
I would assume that this cap is around ~10nf, it is just to filter the current-feedback.
On the Typical Application Circutis in the datasheet of the L6561, there is no capacitor in that position,
maybe it works even without...

Re: Dell 2407WFPb Monitor - Bad Cap

Thank you.
Yes it is the same board, but unfortunately there are only the Electrolytic caps listed.
C626 is an SMD ceramic cap.

Re: Dell 2407WFPb Monitor - Bad Cap

I am currently working on a Power-Supply of a 2407WFPb.
Trough the help of you in this awesome Forum, i was able to find replacement-Parts for all dead components on my board, with exception of one:
On my board, C626 is dead as well. Does anyone know, what capacity C626 is?
Would be great to have more information on that.

btw:
If anyone needs more inforamtion about this board:
I have drawan the complete scematic of that board (currently only by hand as a draft) by following the traces and mesaunring the...