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Michael Hannigan
Michael Hannigan, Technician
Category: TV
Satisfied Customers: 11169
Experience:  25+ Years Experience in Computers and Electronics
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I have a Sony KDL-46EX400. After being off overnight, it

Customer Question

I have a Sony KDL-46EX400. After being off overnight, it will come on and play fine for half an hour or so then shut of like it was turned off. If you unplug and wait a few minuets it will turn back on and play for a few minuets and shuts off much faster.
Submitted: 9 months ago.
Category: TV
Expert:  Michael Hannigan replied 9 months ago.

Hello. Thank you for coming to JustAnswer.

Sorry for the wait. My name is Michael. I will be helping you with your question today.

Please let me know if there as any additional information that you think might be pertinent to your question. If not, I'll provide the best answer I can based on the information you've provided. You can always reply with additional information or questions at any point during our conversation, and I'll be happy to continue helping.

Expert:  Michael Hannigan replied 9 months ago.

The first thing I did for you was uploaed the service manual so you can download that and have something to work from. You can download the service manual at the following link:

http://www.brainchamber.com/downloads/sony-kdl-46ex400-service-manual-az1-k-chassis/

Initially, I would open the TV and do a visual inspection of all capacitors - make sure there are no bulging or leaking capacitors. Failing capacitors can cause exactly what you describe. If so, then simply replacing them will be sufficient. Ohterwise, follow the troubleshooting procedures in the PDF to diagnose.

Mike

Customer: replied 9 months ago.

Hi Mike,

Sorry, I just got back in town. I get a 4 blink error code when the TV shuts down. The error stored in memory is 4, balancer. I have measured resistance on all transformers on the inverter board and all measure the same. Last time it ran for 5 hrs before shutdown, since only seconds. When the TV shuts down the PS_On voltage stays at 3.0V.

Thanks,

Expert:  Michael Hannigan replied 9 months ago.

The balance error indicates that the LEDs are not balanced, and either they are failing, or more likely, the LED driver board.

I would replace the LED driver board.

Mike

Customer: replied 9 months ago.

Hi,

Thanks for the reply, but this set has ccfl lamps. I lit all lamps individually with a lamp tester and all lit brightly. As I mentioned above I checked resistance on all transformers on the inverter board and all checked the same. The high voltage transformer for the inverter is located on the power board. I suspect one of these boards. The error says balancer or panel, but I don't know where the error detect line is generated.

Thanks

I still haven't received an appropriate answer to my last response!

Expert:  Michael Hannigan replied 9 months ago.

The balance error applies to CFLs as well.

You would have to be measuring it at the exact time that it shuts down to see the change.

Did you not get the service manual I uploaded for you?

Customer: replied 9 months ago.

yes, I got the service manual.

Expert:  Michael Hannigan replied 9 months ago.

Ok... in the service manual is the schematic. The inverter are down by the power supply. You are correct that the error refers to the panel, but this isn't usually the case in reality. It's directly related to the back-lighting. If it detects a change in the voltage or resistance, it will give this error and shut it down.

Customer: replied 9 months ago.

Ok, The power board/inverter supplies the high voltage to the inverter board witch connects to the ccfl lamps inside the panel. When the error occurs the 3.3 V backlight on drops off and the backlight err goes up to 3.3V. The Power_on line stays at 3.0V, or sometimes drops off to 0.V, or sometimes the TV reboots. My question is it the power/inverter board, the inverter board, or the ccfl lamps? I ordered and received a new inverter board today per your response, and it didn't help.

Expert:  Michael Hannigan replied 9 months ago.

It's usually the inverter or driver board. But it CAN be the lamps - if the lamp fails, the backlight err goes up and triggers the balance error. The basic meaning of the balance error is that there is an imbalance among the back-lights. I originally referred to LEDs by mistake - in that case, they are just LED strips. In this case, the same thing is true, but with the CCFLs.

Customer: replied 9 months ago.

What about the high voltage transformer circuit on the power board that feeds the inverter board? Wouldn't a failure there trigger and error also? How do I proceed?