Samsung PN50A550S1F does not turn on, relay clicks.

[tom66]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

That is correct.

[EsqzMe]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

Well...
Installed 270 ohm 1/2 watt resistors between the PS-ON and Gnd and the Vs-on and 5.3 v on the Power board end of the cable from the Logic board to the Power Board (cable connected).
I unplugged the cable from the Power Board to the Main Board at the Main.
I jumped the #3 and 4 pins on the test point on the Logic Board.

Plugged in the power cord. Green LED on Power Board lights up. No relay click, no stand-by light. Press On...use remote On...nothing. No test pattern, no relay click on power supply...

Undo all jumps and plug in Main Board. Connect power and back to relay clicking, Green LED on, stand-by light on for about 10 seconds ( several attempts by the relay to "catch" if you will), then stand-by light out, relay stops clicking and green LED on power Board blinking in series of 7.

[tom66]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

Do you have a digital multimeter? With those jumpers in place, check the Vs and Va test points on the power supply.

[EsqzMe]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

I got zero

[EsqzMe]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

I have double and triple checked my connections. With jumpers in place and Main board unplugged there is no voltage on the Vs or Va test points. There is no voltage at the 5.3 v connections to the main board. The relay on the power board does not click, there is no standby light. I have checked all the fuses and I have voltage at fuses on the Hot side of the power board. The single LED on the power board is lit.

Plug the Main board back in and original symptoms return with blinking stand-by on front panel and LED on power board after relay stops clicking.

[EsqzMe]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

I have double and triple checked my connections.
With power board cable to main board unplugged at main, resistor jumps and test pin jump in place, the relay does not click when AC power is attached. The stand-by light does not come on. The LED on power board comes on steady.
There is NO voltage at Va or Vs test points, nor is there 5.3 volts at the cable where the resistor jumps are installed.
Screen is blank.

Remove jumps, plug in main board and apply AC power and symptoms return. Relay clicks for a bit and stops. Stand-by light comes on blinking and LED on power board is blinking.

I'm thinking Power Supply, but maybe Main is bad...or both? Or Logic board?

See photos

[mmartell]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

OK, disconnect the power connector from power to main, on the main board end. Connect the PS-ON to GND via one resistor and VS-ON to 5.3V via the other. Vs, Va should then come up. Then put the jumper on the control board and test patterns should appear.

Shouldn't PS-ON be pulled high instead of low ?

[EsqzMe]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

So Tom66.....any further suggestions? Replace power board? Main board? Logic board? Or all three?

[tom66]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

Shouldn't PS-ON be pulled high instead of low ?

On these sets it's low for PS-ON high for VS-ON don't ask me why...

[tom66]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

OK when the relay clicks with the main board attached does the Vs/Va come up?
What value resistors did you use?

[EsqzMe]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

No voltage measured.
None on the 5.3 pins on the plug to the logic board either.

270 ohm 1/2 watt.

[tom66]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

OK, repeat the test, but this time with X- and Y-main disconnected, do Vs/Va rise?
It is looking like the power board is bad but I do not know why you get no relay clicks with the test jig.

[EsqzMe]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

Same results with X and Y Mains disconnected. No relay click with Main board unplugged and no voltage measured, relay clicks with Main connected and still no voltage.

[tom66]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

OK, I would not have immediately considered this but it does seem like your power board is bad. Check any visible fuses on it, including ones away from the mains power input.

[EsqzMe]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

All the fuses are good.....unless there is a hidden one somewhere.

Found just about every circuit board available on eBay EXCEPT the power board....figures.

I can replace bad components, and know where to buy them if they are generic parts, but other than multimeters I have no test equipment.

[tom66]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

Is there a BN44-xxxxxxA number written on the power board?

[EsqzMe]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

BN44-00222a

And I found plenty of them...in China!!! and some repair shops as well.

And from Samsungparts.com this board interchanges to the BN44-00237A

[tom66]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

I have xx237 schematic but unfortunately no xx222.


Maybe ordering from China is the only option, if you pay with PayPal or another provider which offers protection you're usually going to be OK.

[EsqzMe]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

I have found the 00237A in the US...but most places are out of stock. Must be a popular item!!! Also a couple of repair services.

I'll buy one and let you know what happens. Thanks for the support and help

...you think I should consider getting one of the other boards as well, or just wait and see first?

[tom66]

Re: Samsung PN50A550S1F does not turn on, relay clicks.

The results observed seem to indicate a problem with the power board only at the moment, that part really needs to work before other parts can be checked.