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Hello, I'm TV Tech1 and I'll be working with you to identify and help you resolve your problem.
Count the number of blinks between pauses when the TV shuts itself off.
The number of blinks is five.
The red LED flashes 5 times.
Looks like we have a bad power supply issue --
Missing 18 Volts. We should check it with a voltmeter. Do you have one ?
Yes I have a voltmeter + some other electronic servicing/repair equipment, scope etc.
Also, I need a circuit diagram of the power supply board
Ok, I have a block diagram and a schematic (its large).
I've made note of the suspected power supply and I suggest disconnecting 1 or 2 connectors that does not power up the BE board and see if the 18 volt supply stays turned on and the 5 blink fail code disappears or changes to another code instead --
BLOCK diagram --
Just checking the power supply for correct voltages as you suggested will let you know in a few days the outcome, hope that's OK with you.
If it is the power supply I should be able to pick one up on ebay at a reasonable price! that would save me time testing likely components.
Thanks for your help so far.
Send the information you retrieve back to me after you disconnect the Lamp's power supply cables to the board along the left or right edge. That's the lamp board, and we do want to see if the power board is dead or the lamp board is.
No 18 volt supply present on the board. there are on;y two connectors on this board (other than the P/S connector -bottom right) one top left and one top right.
With one or the other or both disconnected there is no 18 volt present. the only voltage that was present was the 3.3 volt.
The red LED 5 flash continued with whatever connection/disconnection.
I don't know what the lamp or BE connection is!
I can't read the part numbers on the circuit diagrams, to blurred.
If you think that it is most probably the Power Supply, I can purchase one reasonably cheaply here in the UK
Before you order a power supply board, listen to your TV set and press the power button. Do you hear the relay click on and off when you press the power button?? That's with both plugs connected onto the power supply. The main board needs to turn that relay on and off, or the AC voltage needs to pre-power up the relay when it's plugged in so the 18 volt supply comes alive.
Yesterday worked fine all day.
Relay not clicking in on power up, or power down
Hmm, odd that it worked ok, then now it doesn't.
Always check the STBY3.3 volt and the Power On and Relay On pins on your power supply board.
You need the STBY 3.3 First. That powers the micro.
The micro sends out the Power on and the Relay On voltages that switch between 0 and 3.3 Volts.
It's possible the power supply just quit making the needed 3.3 volts to get the TV started up.
Intermittent again hence delay in my answer. 3.3 volts always present working or not. Power ON and Relay ON (3.3 volts) when working OK, but both 0 volts when not working. Incidentally where/how is the 3.3 voltage generated?
Tested the relay with independent 12 volts, contacts not sticking.
Ok, the 3.3 volts should be created on the power supply board and is usually labeled as 3.3 STBY....or it may be 5V STBY. I doubt the 5V....that would mean the MAIN board would have a 3.3 volt regulator on it to power up the micro.
Now the micro is important. IT CREATES the Power on and Relay ON voltages and sends them back to the power supply board to turn on the rest of the power supply.
You stated --
Power ON and Relay ON (3.3 volts) when working OK, but both 0 volts when not working.
If your power supply is supplying that STBY voltage and you don't see 3.3 volts on those pins....the main is not turning on the power supply, and is the problem.