Samsung ps50b451

[sordids999]

hello

got this tv today when you turn it on just clicking tried disconnecting the boards one by one but still clicking any ideas ?

thanks

[tom66]

Re: Samsung ps50b451

Check the Vs/Va voltages on the power supply. Do they rise or not. Also check if the logic board light flashes at all.

[sordids999]

Re: Samsung ps50b451

Hi tom
Vs no reading va starts at 15 volts then goes to 12 volts then back up and the logic board is flashing

[tom66]

Re: Samsung ps50b451

Any difference with Y- and X-main boards disconnected?

[sordids999]

Re: Samsung ps50b451

Still the same with x main and y main disconnected separately also just noticed vs reading rises but it's barely 1volt

[tom66]

Re: Samsung ps50b451

OK so it will be necessary to eliminate the main AV board from the tests for now.

Plug in the X- and Y-main power connectors again.
Unplug the AV board main power connector, from the main board end.
Jumper pin PSON to GND, pin VSON to 5VSTBY (or similar standby pin.)

Plug the set in & confirm if you get Vs & Va and if they are stable. You may also get a slight glow from the display.

[sordids999]

Re: Samsung ps50b451

Ok jumped what you requested the logic board lights up but then goes out vs and va no readings

[tom66]

Re: Samsung ps50b451

OK, can you repeat that test with the Y-main and X-main disconnected. May be a PSU issue; try checking the fuses on the PSU. Also possible it's a control board issue, that can be eliminated later.

[sordids999]

Re: Samsung ps50b451

Va 55 volts vs 206 volts

[sordids999]

Re: Samsung ps50b451

And fuses ok on psu

[tom66]

Re: Samsung ps50b451

Looks like there might be two problems here.
A bad main board and a bad X- or Y-main board.

Try with just X or Y in to isolate that. Then check for bad transistors on the board which is shutting down the PSU.

[sordids999]

Re: Samsung ps50b451

i have a spare main board BN41-1180B BN94-02844C but the board in the tv is BN41-1180A BN94-02645A the fittings are the same would this work just to test it

[sordids999]

Re: Samsung ps50b451

ive tried y and x separately but still no voltages on vs and va and clicking still

[tom66]

Re: Samsung ps50b451

i have a spare main board BN41-1180B BN94-02844C but the board in the tv is BN41-1180A BN94-02645A the fittings are the same would this work just to test it

Should be OK, if all connectors are identical & it's from a 50" panel. Even if it is from a 42" panel it will be ok for a test though you will need a 50" mainboard for it to work properly.

May need to consider a control board fault, try main board first.

[sordids999]

Re: Samsung ps50b451

ok fitted main board still the same clicking on and off no vs or va voltages

[sordids999]

Re: Samsung ps50b451

hold on disconnected both x and y samsung chime came up on tv vs 206 volts va 56 volts ill try one by one now

[sordids999]

Re: Samsung ps50b451

nope both x and y one by one disconnected still clicking so only works if both are disconnected so does that mean they are both faulty ?

[tom66]

Re: Samsung ps50b451

It is possible. Check both for shorted transistors. I am aware that some of these Samsung panels can kill the Y-buffer, X- and Y-main boards all at once... bit of a bugger when that happens. On this set, the Y-buffer is integrated into the Y-main.

It does also look like the main board was bad too which is odd.

[sordids999]

Re: Samsung ps50b451

ok back up for 5am work calls so ill check this out first thing tommorow night

thanks for your help tom

[sordids999]

Re: Samsung ps50b451

Hi tom ive been looking around at the boards and noticed this:
Please also check the board for shorts across large green resistors R905, R906 setting your meter on diode test. The correct value is about 0.7V one way and no reading the other. If low readings both ways

DO NOT POST THE BOARD AS YOUR BUFFER ADDRESS ICS ARE BLOWN

ive tested mine and im getting 0.715 and no reading the other way some im thinking my ICS are good ?

right with regards to testing the transistors can u test in board or remove one by one to test ?