samsung pn50a550s1fxa power supply

[awyatt2]

anyone familar with pn50a550s1fxa power supply? i have two bad diodes heatsink mounted.ds824 and ds825. i have no luck with the schematic or service manual. plenty of hits on reviews. long story but previous owner states dog gnawed thru power cord and after replacing cord it was dead.can post pic but there appears to be no physical damage but the diodes are shorted. they have weird numbers and i cant cross them to anything.

[tom66]

Re: samsung pn50a550s1fxa power supply

Whereabouts on PSU are they? Primary/Hot or Secondary/Cold side?

[awyatt2]

Re: samsung pn50a550s1fxa power supply

secondary, 3 legs to220 case bolted to heatsink. one appears marked anode to anode other cathode to cathode. i have seen this type before never seen the markings though

[tom66]

Re: samsung pn50a550s1fxa power supply

secondary, 3 legs to220 case bolted to heatsink. one appears marked anode to anode other cathode to cathode. i have seen this type before never seen the markings though

Can you trace what voltage output they are on? What are the markings on the diodes?

[awyatt2]

Re: samsung pn50a550s1fxa power supply

no, cant trace voltage back it is dead until i get the two diodes replaced. numbers are fcu10uc30 and fru10uc30.

[awyatt2]

Re: samsung pn50a550s1fxa power supply

they are switching diodes samsung part store came up with them and as always out of stock.

[tom66]

Re: samsung pn50a550s1fxa power supply

no, cant trace voltage back it is dead until i get the two diodes replaced. numbers are fcu10uc30 and fru10uc30.

100V 30A Dual Schottky diode probably. You can't follow the usually labelled power outputs to find what output they are on?

[awyatt2]

Re: samsung pn50a550s1fxa power supply

no they are on the output of an xformer

[tom66]

Re: samsung pn50a550s1fxa power supply

no they are on the output of an xformer

And they go into some caps... which have a voltage rating of XYZ... (maybe through an inductor... and then some caps which have a voltage rating of XYZ...) and then into a connector... which has a labelled voltage of XYZ...

Replace "XYZ" with appropriate values.

[awyatt2]

Re: samsung pn50a550s1fxa power supply

the caps have a rating of 250v one is common anode and one is common cathode. center lec being common, two anode and two cathode.the connector is labeled=vs,vs,nc,rtn,rtn, vg

[awyatt2]

Re: samsung pn50a550s1fxa power supply

i just got it running, its a temp job to see if anything else was fried. good news is she is 100%.took two 5amp 1000v switching diodes and made one the other came out of an old computer supply. gonna try and order diodes tomorrow morning. thanks, guess i was looking for an easy way out.

[tom66]

Re: samsung pn50a550s1fxa power supply

the caps have a rating of 250v one is common anode and one is common cathode. center lec being common, two anode and two cathode.the connector is labeled=vs,vs,nc,rtn,rtn, vg

Oh, plasma TV. Okay, should have realised from "pn".

Try 300V fast recovery 10A like this.

http://search.digikey.com/us/en/prod...WGI-ND/1147822

[awyatt2]

Re: samsung pn50a550s1fxa power supply

time to update this a bit, finally found a pair of diodes that work, they need to be insulated from the heatsink though. they are available at mouser electronics, so far with these no problems.mur1620ctrg is com dual anode andmur1620ctg common dual cathode. these are 16 amp 200v original was 10 at 200v.so far they are doing the job. I used the silicone type pads instead of mica for insulators.

[zape]

Re: samsung pn50a550s1fxa power supply

Do you think mur1620ctg will work as the FCU10UC30 replacement if the rectified voltage is 202v?
I'm currently looking at these SDURF2030CT https://www.digikey.com/scripts/DkSe...17855932124438
A bit higher recovery time but overall good match

[awyatt2]

Re: samsung pn50a550s1fxa power supply

they should, mine is still good with the mur1620's.wish I could have found something with the insulated case. I used silicone wafers and nylon screws to isolate the case from the heat sink.

[ajshoe]

Re: samsung pn50a550s1fxa power supply

so will the SDURF2030CT & SDURF2030CTR work as a sub for these common dual diodes ?

[zape]

Re: samsung pn50a550s1fxa power supply

SDURF2040CT worked fine for me.