Re: Dell E172fpb

If Q759 and Q760 are getting very Hot; chances are that one of the switching transformer coils are shorted (T751 or T753). Also check (C754 C755) which lies across the collectors of Q759 and Q760. These caps dampen the voltage and current across the tranny's (V*I=P (Watts=heat)). I am under the assumption that Q759 and Q760 are not failing (have you removed, and metered them individually?).

Resistance from Emitter to Collector (Ohm'd out in both directions) should be infinite. Also, to test the switching transformers you will need to perform a "Ringer"...

Re: Dell E172fpb

Yes, [B]FU9024N[/B] is the same as [B]IRFU9024N[/B]... The "IR" merely indicates the company name (International Rectifier). I have found that Digikey ([url]www.digikey.com[/url]) carries this component... there you will find IRFU9024NPbF (the PbF indicates that this is the Lead free version).Re: Dell E172fpb

Yes, [B]FU9024N[/B] is the same as [B]IRFU9024N[/B]... The "IR" merely indicates the company name (International Rectifier). I have found that Digikey ([url]www.digikey.com[/url]) carries this component... there you will find

Re: Dell E172fpb

Regarding my previous post... The attached schematic (from model DV172) does not completely reflect the E172fpb's circuitry. In comparison the F172fpb is similar to that of the DV model schematic referenced; however the short circuit protection, as well as the feedback loop, are VERY different (much more complex). I believe this is where the design flaw is at. When designing any switch mode power supply feedback and short circuit protection (SCP) are critical. If any components in this region are not optimized, changes due to temp, fault... may cause failures (i.e....

Re: Dell E172fpb

I am an Electrical Engineering student and purchased this monitor broken because I'm cheap… and well, I'm learning how to design these things. I have curiously been following this thread and finally decided to contribute. Hopefully this may shed some light on thing or two… or possibly confuse some. READ the attached pdf files. I've also included a schematic from a very similar Benq Inverter board... Enjoy ...