Samsung PN50550T Won't Turn On!

[tom66]

Re: Samsung PN50550T Won't Turn On!

That's very odd...
Can you try the test again, but with the resistors/wire in the main board connector instead?

[coppercitycomputer]

Re: Samsung PN50550T Won't Turn On!

There is no VS-On to the input/main board, only PS-On shorting that to ground has no effect.

[tom66]

Re: Samsung PN50550T Won't Turn On!

Well, something is not right. If you do that jumpering, you SHOULD get a relay click. I'm not able to explain why you do not. Can you check the voltage on the VSON and PSON with the resistors installed?

[coppercitycomputer]

Re: Samsung PN50550T Won't Turn On!

Ok I went back to the drawing board ;-)

With VSon 100Ohm to 5.3V and PS-On grounded to chassie and main/input board uplugged and controller unplugged. I get a loud click then a 2nd more quite one.

Ok hopeful that's right, what's next?

[tom66]

Re: Samsung PN50550T Won't Turn On!

OK, that's better. Now, in that configuration, do you get Va & Va voltages? If not, do they come back with X- and Y-main disconnected?

[coppercitycomputer]

Re: Samsung PN50550T Won't Turn On!

Ok with the X and Y connected, the power supply clicks on then clicks off, voltage's fall, With the X and Y Removed the power supply clicks but dose not click off and I hear whine but the voltage still falls.

[tom66]

Re: Samsung PN50550T Won't Turn On!

Does it rise at all? Or not?

[coppercitycomputer]

Re: Samsung PN50550T Won't Turn On!

The voltage go's higher with the X and Y unplugged about 15 volts and 5 volts, with the X and Y plugged up it's only makes it to about 8 volts. Then they fall off after few secs. regardless of the X and Y being plugged or not!

[coppercitycomputer]

Re: Samsung PN50550T Won't Turn On!

What should I do next?

[tom66]

Re: Samsung PN50550T Won't Turn On!

It seems the power board is not working properly.

[coppercitycomputer]

Re: Samsung PN50550T Won't Turn On!

Any way to test the power board and replace compents or just replace it?

[tom66]

Re: Samsung PN50550T Won't Turn On!

There are a few tests. Can you read off the BN44 number on the power board?

[coppercitycomputer]

Re: Samsung PN50550T Won't Turn On!

BN44-00274A. Should I remove the power board?

[tom66]

Re: Samsung PN50550T Won't Turn On!

Not for now. Will try & find schematic.

[tom66]

Re: Samsung PN50550T Won't Turn On!

Top result:-
http://www.tgohome.com/ServiceManual...&Search=Submit

Board JUMPERED ON (measure after two relay clicks - CAREFUL PRIMARY SIDE - HIGH VOLTAGE):
- voltage across: any of CP801/CP802/CP803 - about 390V
- voltage across: CQ815, CQ807, CB803, CS847, CS846 (if present)

Check the following for short circuits, may be done with board installed or removed:
- DS825
- DS824
- DS801
- DS800

[coppercitycomputer]

Re: Samsung PN50550T Won't Turn On!

Don't know how read it or if it's the right sheet but would this help?

[tom66]

Re: Samsung PN50550T Won't Turn On!

See above, already linked.

[coppercitycomputer]

Re: Samsung PN50550T Won't Turn On!

All of CP801 CP802 and CP803 have 390V Voltages from CQ815 (19.8V), CQ807 (13V), CB803(16V), CS847 (15V), CS846 (if present) Not found.


Are these rectifiers and how do I test them?
- DS825
- DS824
- DS801
- DS800

[tom66]

Re: Samsung PN50550T Won't Turn On!

Please reconfirm CQ807 voltage, it should be about 15V.

They are diodes/rectifiers yes. For the diodes, you should take the red and black probes and put them across all three combinations of pins. Mentally number the pins 1 thru 3. Order does not matter just be consistent between each device. Test 1-2, 1-3, 2-1, 2-3, 3-1, 3-2 (Red-Black) and note reading for each. I am expecting shorts for some combinations due to them being in circuit - this is OK.

[coppercitycomputer]

Re: Samsung PN50550T Won't Turn On!

The CQ807 voltage is 15v! 1 is unlimited on my meter 0 is shorted. I did not find DS800.

Red on Pin 1, Black Pin 2 DS824 1 DS825 414 DS801 1

Red on pin 2 Black On Pin 1 DS824 420 DS825 1 DS801 1

Black Pin 2 Red pin 3 DS824 1 DS825 414 DS801 454

Red Pin 2 Black Pin 3 DS824 419 DS825 1 DS801 1

Hope that is right! That is with the low voltage side towards me, AC input in the upper right corner