PSU - BN44-00878A
Symptoms:
The TV turned itself off, and I haven't been able to turn it back on. The standby voltage was unstable and lower than it should be.
A weak clicking sound was coming from the transformer.
Video with clicking sound:https://www.youtube.com/watch?v=lAduhjNtqCA
Progress:
After the transformer, I measured four Schottky diodes. DM862C and DM864C diodes readings were 003 in both directions. After detaching them from the circuit and measuring them, DM864C was the shorted one. These Schottky diodes are SB550.I purchased SB560 (because SB550 was unavailable) and replaced all four diodes.
Then I measured the standby voltage, which was stable but slightly higher (9.5 when the TV is turned off and 12.83 when the TV is turned on).
After attaching all cables, i managed to turn the TV on. I tried it without the OneConnect box a few times.
The clicking sound from the transformer was still present while the TV was off, but the clicks were faster (shorter intervals between clicks). When the TV is on, a clicking sound is not present.
After connecting the OneConnect box and input sources and turning it on the tv was fine for few minutes, but then all of the previous symptoms reappeared.
DM864C was shorted again.
On youtube i found that solder joints on transformer can be cold, so i reflowed all transformer joints, and replaced shorted diode, and tv is now working.
But, when tv is in standby I can hear fast clicking noise. Noise is almost silent, I must bring my ear very close to it. And it's coming from primary side before transformer, I guess relay..
What can be causing this clicking?
Symptoms:
The TV turned itself off, and I haven't been able to turn it back on. The standby voltage was unstable and lower than it should be.
A weak clicking sound was coming from the transformer.
Video with clicking sound:https://www.youtube.com/watch?v=lAduhjNtqCA
Progress:
After the transformer, I measured four Schottky diodes. DM862C and DM864C diodes readings were 003 in both directions. After detaching them from the circuit and measuring them, DM864C was the shorted one. These Schottky diodes are SB550.I purchased SB560 (because SB550 was unavailable) and replaced all four diodes.
Then I measured the standby voltage, which was stable but slightly higher (9.5 when the TV is turned off and 12.83 when the TV is turned on).
After attaching all cables, i managed to turn the TV on. I tried it without the OneConnect box a few times.
The clicking sound from the transformer was still present while the TV was off, but the clicks were faster (shorter intervals between clicks). When the TV is on, a clicking sound is not present.
After connecting the OneConnect box and input sources and turning it on the tv was fine for few minutes, but then all of the previous symptoms reappeared.
DM864C was shorted again.
On youtube i found that solder joints on transformer can be cold, so i reflowed all transformer joints, and replaced shorted diode, and tv is now working.
But, when tv is in standby I can hear fast clicking noise. Noise is almost silent, I must bring my ear very close to it. And it's coming from primary side before transformer, I guess relay..
What can be causing this clicking?
Attached Files
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