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SONY KDL-40BX450 Will not power on    
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drsw



Joined: 29 Nov 2014
Posts: 2
Location: Clearwater

PostPosted: Sat Nov 29, 2014 11:04 am    Post subject: SONY KDL-40BX450 Will not power on Reply with quote

My Sony is no longer working. When you plug the unit it it turns on. It loads the Sony image and then the display suddenly shuts off. It continues to do this repeatedly. It does not power down. The red light never comes on. The green light only flashes when the display comes back on. At times the display will last long enough to where I can power down the tv and the red light comes on but once I power it back on it repeats the same process. I have hidden all the controllers, I have connected it straight to the wall, I have disconnected everything attached to it and I have let it go for about 15 minutes and it still continues the same antics. Any suggestions. I have a video of it if I can upload it.
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JTS1957



Joined: 21 Jan 2009
Posts: 2305
Location: Far, Far Away

PostPosted: Sat Nov 29, 2014 1:50 pm    Post subject: Reply with quote

First step is to open the set and give it a good visual exam. Look for obvious burnt or discolored part(s), 'bursted' / bulged / leaky electrolytic capacitors (especially on power and backlight board(s), etc.
drsw



Joined: 29 Nov 2014
Posts: 2
Location: Clearwater

PostPosted: Sat Nov 29, 2014 1:57 pm    Post subject: Open the set Reply with quote

We opened the set last night and did not see anything that seemed to be problematic. We also tried turning the tv on with the back off to listen to sounds or see something obvious but we did not see anything wrong.
JTS1957



Joined: 21 Jan 2009
Posts: 2305
Location: Far, Far Away

PostPosted: Sat Nov 29, 2014 2:53 pm    Post subject: Reply with quote

Critical voltages and circuit operations are monitored by the CPU on the Main Board. If an error is detected the Self Diagnosis function in the TV will force the TV to shut down by the CPU. The monitored circuit in which the fault occurred will automatically cause the CPU to blink the Standby LED in groups of repeating sequences. The number of times the Standby LED blinks indicates the possible cause of the problem.

NO diagnostic code?
================================

Can you take voltage measurements at CN6402? Ground (reference) is pins #6 to 10. I'd like to know DCV on Pins #1 to 5; Pin #11; Pin #12 & Pin #14.
You will need to take these twice. I need to see what voltages are there and if they change as the display turns on & off.
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