On Wed, 16 Nov 2022 17:25:07 -0800, RosemontCrest <
b...@post.com>
wrote:
Check the voltages on the connector to the backlight, and currents,
if possible. You should eliminate problems there, first.
You'll likely only be able to tell if the problem is with wiring
or lamps inside the backplane area after dismantling. You should
be prepared to replace the lamp strips at that time, because the
longer it's disassembled, and the more times you repeat that
operation, the more chance of damage in the process.
Most sets won't let you see a dead lamp strip - just shutting
down, which is most annoying. A lot of these things would be
capable of running with multiple single led failures in their
strips and no real difference in display quality . . .
. . . but the designer thinks differently.
A repair can often be made by simply jumpering the defective
led with a suitable voltage dropping resistor or zener, but
this is only something I'd do if replacement strips
weren't on-hand.
I had one set where a dead strip could be mimicked with a
10W power shunt on that line, without opening the thing up.
Dispay was acceptible to the customer, so it went back
with just that addition. Not a real fix and a symptom
that all the lamps needed replacement, but sometimes
quicker is better.
RL