samsung TV ps-42q97hd clicking

[cossiejay]

]hi all i have a samsung TV ps-42q97hd uk model 240 volts the power board is a bn44-00161a that is clicking i have replaced all capacitors,the mosfets,risistors and 2 diodes that came with a kit from ebay but it is still clicking any help please
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[jwcelectronics]

Re: samsung TV ps-42q97hd clicking

hi,
I have come across this fault on other models and I have found that there is a 16volt zener that goes open under load near the standby transformer check it out of pcb.
if this ok the try this link.
https://www.youtube.com/watch?v=wmJenmz9vro

[jwcelectronics]

Re: samsung TV ps-42q97hd clicking

also I have come across that if the y & z boards are disconnected and the control board led still flashers it could be the panel has a short.
do you have vs and va? voltages.
if the set is doing nothing completely dead just clicking then check to see if you have 5 volts on the main board feed due to this being to tell the microcontroller to switch on the rest of the power board.
something silly as a fuse able resister can give you hassle ( been there before)
hope this helps you out.

[flocko]

Re: samsung TV ps-42q97hd clicking

Try powering the board out of the set this is the best way to go, but take care as high voltage, with the mains connected you should see 5v standby on the white connector bottom right there will be no click from the relay if that's there,put PS-on low with a 500 ohm resistor to grd the relay should now click and you should find the 13v and 5v TP come up, if these are there Put 500ohm resistor between VS-on and Standby to bring Vs and Va voltages up, if this all works you have a short on the Y or Xsus or Y buffer Flocko

[Dans2530]

Re: samsung TV ps-42q97hd clicking

If this board doesn't work powered up by itself, and there isn't any cold solder or burnt out components, check the two sub boards with the MC33067 ICs. On my board that I repaired, the smd Zener diode and the totem pole transistors were busted. I replaced them and the ic as well and it worked fine after that.

On the top sub board it is diode DS823, check that for open or short (mine was open), and test transistors QS803,QS804,QS805 and QS806. If any of these aren't good, replace the lot and the ic for good measure. I used discrete components instead of smd as they were more easily available to me.

[cossiejay]

Re: samsung TV ps-42q97hd clicking

replaced the power board all good now cheers

[tonydix]

Re: samsung TV ps-42q97hd clicking

Flocko thanks for the advice. 500 ohm between pson and ground produces relay click. 500ohm resistor between VS-on and Standby does not bring Vs and Va voltages up.
I have reflowed and checked all dodgy electrolytics. Any ideas please. Many thanks . Tony

[R_J]

Re: samsung TV ps-42q97hd clicking

You may need a load on the Vs or Va lines, I know the hitachi power supplies need a load or the voltage only comes up for a split second then shuts down, depending on the expected voltage, use one or two incandescent lamps.
The schematic does show ovp lines on both Vs and Va
Also I think this BN44-00161a board has error led's on it which might indicate where the problem is?

[tonydix]

Re: samsung TV ps-42q97hd clicking

Thanks R_J you were quite correct. Setup the board as described with a bulb load as in Andrew Ali' post #64941. Bulb lights but pulses regularly with 1 pulse per second. Vs voltage fluctuates between about 170 volts and 200 volts. Never quite reaches the required 207. Any ideas ? I made a video but don't seem to be able to link it. Thanks. Tony

[tonydix]

Re: samsung TV ps-42q97hd clicking

After further tests I now think the pulsing may relate to the isolation transformer I was running it through. Plugged it into the mains directly and immediately fried the two diodes DS888 and DS889. Suppose the 240 volt bulb I used had insufficient resistance and allowed too much current to pass when the supply was solid. Must now try to source the 2 diodes UGH !