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Old 10-20-2019, 11:18 AM   #1
imran333
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Default Sony kdl-46w905a wonít turn on and relay clicking noise

Hi I got Sony kdl-46w905a and it wonít turn on and no red blinking code and all I hear when I plug it in is a clicking noise and a pause for a second then another clicking noise as if the power supply has a relay and is relay is turning off the power supply bcuz of a problem, bcuz of this I have no way to check voltages anywhere as thereís no standby light but I think I get a white light for a second then goes off, Iíve checked for bad capacitors or shorted mosfets but havenít found a problem, and I was thinking if thereís a way To bypass the protection so it stays on so I can check voltages ? Or maybe someone can help me on what to try ?
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Old 10-20-2019, 12:09 PM   #2
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

Unplug from power, unhook cable from powerboard to mainboard, plug power back into powerboard, do backlights come on and is the clicking the same?
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Old 10-20-2019, 12:59 PM   #3
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

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Originally Posted by nomoresonys View Post
Unplug from power, unhook cable from powerboard to mainboard, plug power back into powerboard, do backlights come on and is the clicking the same?
Iíve tried unplugging cables from each board but no difference and no backlight
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Old 10-20-2019, 01:03 PM   #4
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

Ok, with everything hooked up do test #3 below, demonstration in #2 if needed, try to do just as instructed, this test is done on the cold side, as always BE VERY CAREFUL when working with the HOT/DEADLY side of powerboard.
__________________
1) https://www.youtube.com/watch?v=4F2J1Dkf4Is
HIGH VOLTAGE HAZARD demonstration. Video by Electronic Doberman.
2) https://www.youtube.com/watch?v=4v8DcqCNG4A
Power supply board voltage testing by shopjimmy.
BE VERY CAREFUL WITH POWERSUPPLY, VOLTAGE ON PRIMARY/HOT SIDE CAN BE DEADLY, THE CAPACITORS CAN HOLD A VERY BIG CHARGE LONG
AFTER TV HAS BEEN UNPLUGGED.
3) Test connector from mainboard to powerboard on powerboard side with all boards hooked up, test with tv plugged in but off then hit power, report both conditions here, give pin number, pin description/name and condition both off and when you hit power on. So we can see all the voltages and what they are doing. Try to do test just as instructed, example in link 2 if needed.

Last edited by nomoresonys; 10-20-2019 at 01:05 PM..
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Old 10-20-2019, 05:40 PM   #5
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

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Originally Posted by nomoresonys View Post
Ok, with everything hooked up do test #3 below, demonstration in #2 if needed, try to do just as instructed, this test is done on the cold side, as always BE VERY CAREFUL when working with the HOT/DEADLY side of powerboard.
I noticed the relay doesnít click when I disconnect the cable from the power supply going to main board, and when itís connected thereís no voltages at all on any pins of the power supply, but when I disconnect cable going to main board then the only voltage I get is stand by voltage 3.3v, but no other voltages are present, and as soon as I connect the cable going to main board with power connected the relay on power supply clicks and stand by voltage is gone, the capacitors on main board i checked voltage, and only getting voltage on the big 400v caps and voltage is around 310v, and it doesnít make a difference if the cable going to main board is connected it disconnected , still only voltage on big caps the test I get no voltage ?
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Old 10-20-2019, 06:39 PM   #6
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

Can you post a good clear picture of the powerboard and the pin labels of the connector if any?
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Old 10-20-2019, 07:16 PM   #7
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

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Originally Posted by nomoresonys View Post
Can you post a good clear picture of the powerboard and the pin labels of the connector if any?
Here pictures of power board
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Old 10-20-2019, 07:51 PM   #8
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

Could try jump starting power board and see if you get the missing voltages, with cable from powerboard to mainboard UNHOOKED, make sure it is, then connect low wattage resistor from POWER..ON to STBY 3.3 and another resistor from STBY 3.3 to BL_ON, power up powerboard, see if you get the missing voltages and if the backlights come on and stay on.
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Old 10-21-2019, 08:50 AM   #9
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

Quote:
Originally Posted by nomoresonys View Post
Could try jump starting power board and see if you get the missing voltages, with cable from powerboard to mainboard UNHOOKED, make sure it is, then connect low wattage resistor from POWER..ON to STBY 3.3 and another resistor from STBY 3.3 to BL_ON, power up powerboard, see if you get the missing voltages and if the backlights come on and stay on.
Iíve never tried that but do you know any videos about doing that and I still donít understand if itís main board or power supply but main board is not available anywhere at the moment but I can get power supply but prefer repairing it
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Old 10-21-2019, 09:26 AM   #10
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

Powerboard the one with the big caps and transformers on it.
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Old 10-21-2019, 09:27 AM   #11
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

Check all your diodes if any read strange take out of circuit and recheck.
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Old 10-21-2019, 09:30 AM   #12
nomoresonys
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

That test in post #8, if passes usually verifies powerboard and backlights, leaving either a mainboard, tcon, panel issue or connection.

Last edited by nomoresonys; 10-21-2019 at 09:49 AM..
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Old 10-21-2019, 09:42 AM   #13
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

Demo there, HEED THE WARNING OF DEADLY VOLTAGES ON HOT SIDE, he used an alligator clip to short pins together, it's recommended to use a resistor so you don't mess up any components in case you accidentally short the wrong pins: https://www.youtube.com/watch?v=mUvclBfaMXg
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Old 10-21-2019, 09:44 AM   #14
imran333
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

Quote:
Originally Posted by nomoresonys View Post
Demo there, HEED THE WARNING OF DEADLY VOLTAGES ON HOT SIDE, he used an alligator clip to short pins together, it's recommended to use a resistor so you don't mess up any components in case you accidentally short the wrong pins: https://www.youtube.com/watch?v=mUvclBfaMXg
Thanks Iíll try and get back but what value resistor is recommended ?
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Old 10-21-2019, 10:49 AM   #15
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Default Re: Sony kdl-46w905a wonít turn on and relay clicking noise

I think usually 1k or less.
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