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From: Eggie on 20 Dec 2009 09:16
mine turned out to be 2 broken ccfl lamps. Like Tony said, it detected low
current on this circuit and shut it down. I ordered 2 new lamps.
Roy


From: PlainBill47 on 20 Dec 2009 14:12
On Thu, 17 Dec 2009 08:09:20 -0800 (PST), jjh <jjhudak(a)gmail.com>
wrote:

>Was working fine until recently, the back light seems to be shutting
>off. After turning on the tv, the screen will light up for about 1-2
>seconds then it will shut off and become black, but the tv remains on
>and working otherwise. Shining a flashlight on the screen indicates
>the picture is there. Audio is OK.
>Anyone know if this is a systemic problem with this TV? If so, is
>there a well-known fix?
>
>Any other thoughts about what could be the root problem?
>So for this model, where is a good place to get replacement parts?
>(e.g. inverter board, lamps)
>
>Thanks
>-John
Common failures of the backlight system include bad capacitors, aging
or broken CCFLs, wiring problems (bad solder joints, arcing) to the
CCFLs, bad transformer, or a fault in the CCFL monitoring circuit.

If you have a DMM and steady nerves, it is possible to isolate the
problem. The first step requires opening the TV and locating the
power supply and the inverter. Look for bulging capacitors in the
power supply and the inverter.

Next look at the leads from the inverter to the CCFLs (backlights).
Usually the wires are in pairs. If the wires in the pairs are of
different diameters the smaller diameter wire is the return line.
Measure the AC voltage on each return line as the backlights are
operating. (Yes, you only have a few seconds). Normally each wire
will have the same voltage; you are looking for the one that is
noticably different than the others.

The other step may require removing the inverter from the TV. With it
unplugged from AC power measure the resistance between the leads of
the transformers. Again, you are looking for the thransformer that is
significantly different than the rest.

PlainBill
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