Fujitsu PDS42xx PSU(PFW-422) info request

kingcobra · Joined: 06 Feb 2008 Posts: 7 Location: Bristol, UK

Hi

Does anyone have any circuit details of the PFW-422 PSU used in the Fujitsu PDS42xx series of plasma display panels please?

I am particulary looking for help in the area of Vsc which appears to be at -44v instaed of +120v. ( off load )

I have the so-called service manual which gives all the output voltages, but no schematics.

Any information would be appreciated.

minnie · Joined: 18 Aug 2005 Posts: 2510 Location: Hell

Per say schematics are not available from any manufacture on plasma's. If your VSC is low/incorrect that would indicate a bad sustain board. You can esr the caps, replace the voltage regulators, look for bad components ect. In other words, guess or replace the sustain board.

Guest · Posted: Wed Feb 06, 2008 4:25 pm Post subject:

Guest · Posted: Wed Feb 06, 2008 5:48 pm Post subject:

With the back off the power supply is middle top, below it digital main, boards to the left and right of the power supply should be the x and y sustain boards.

Guest · Posted: Thu Feb 07, 2008 10:49 am Post subject:

Thanks - I see which boards you mean, but what is Vsc used for? - logically it would seem to be a supply FROM the PSU, but from what you have said it seems to come from the sustain board(s) and TO the PSU. If it were PSU derived (and the PSU is OK), surely it would be correct when the sustain board is disconnected?

minnie · Joined: 18 Aug 2005 Posts: 2510 Location: Hell

Check the fuse's on the sustain brd. Unplug the connector if the Vsc doesn't come back up yes a bad PS.

kingcobra · Joined: 06 Feb 2008 Posts: 7 Location: Bristol, UK

Hi
I don't see any fuses on the sustain boards, but I'm fairly sure the PSU is OK and that something is tripping it (red led flashes continously). It's only when I disconnect Vcc1 on CN42 that it stays up and running. What I thought was an incorrect Vsc, I now think is correct when measuerd with respect to -Vy instead of 0v. Could a fault with the Plasma display itself cause the PSU to trip?

minnie · Joined: 18 Aug 2005 Posts: 2510 Location: Hell

Say that again, you unplug CN 42 which goes to the sustain board and the voltage is correct???

kingcobra · Joined: 06 Feb 2008 Posts: 7 Location: Bristol, UK

Yes - unplugging CN42 allows the PSU to start up normally(green led) and all voltages appear to be correct. The same happens by just removing Vcc1(pin 6 of CN42)

minnie · Joined: 18 Aug 2005 Posts: 2510 Location: Hell

Bad sustain board or bad panel.