Hello All
I have the above TV in my shop for what was called a "flicker".
The screen brightness? or contrast? would go up and down making the screen appear to flicker.
My first thought was the backlights but pulling the connector from the tcom put them on and they are solid and steady.
Next I thought it was a bad tab connection so I swapped the entire panel - it's still happening!
So I started looking at voltages with my scope and noticed they are all jittering about, I followed back from the Tcon board to the main board and then into the power supply board and found it jitters all the way back to the 12V and 15V from the power supply.
To make sure it wasn't a load problem I disconnected the outputs from the power supply to both the inverter and the main board and applied AC, I only get the 3.3V STBY but it's flickering too!
Since the 3.3V STBY and the 12V and 15V lines come from different transformers and ICs I thought that maybe the 395 PFC was bad but while trying to measure it all I did was blow the main fuse. HINT: don't hook a grounded scope lead to the 395V PFC ground - they aren't the same
So before I start ordering and replaceing CXA ICs or FETs I thought I'd ask if anyone else has seen this and could give me a pointer.
Jeff
I have the above TV in my shop for what was called a "flicker".
The screen brightness? or contrast? would go up and down making the screen appear to flicker.
My first thought was the backlights but pulling the connector from the tcom put them on and they are solid and steady.
Next I thought it was a bad tab connection so I swapped the entire panel - it's still happening!
So I started looking at voltages with my scope and noticed they are all jittering about, I followed back from the Tcon board to the main board and then into the power supply board and found it jitters all the way back to the 12V and 15V from the power supply.
To make sure it wasn't a load problem I disconnected the outputs from the power supply to both the inverter and the main board and applied AC, I only get the 3.3V STBY but it's flickering too!
Since the 3.3V STBY and the 12V and 15V lines come from different transformers and ICs I thought that maybe the 395 PFC was bad but while trying to measure it all I did was blow the main fuse. HINT: don't hook a grounded scope lead to the 395V PFC ground - they aren't the same
So before I start ordering and replaceing CXA ICs or FETs I thought I'd ask if anyone else has seen this and could give me a pointer.
Jeff
