PANASONIC Viera L32X9D2 LCD TV Repair Help - SERVICE EXPERIENCE
The
set got for repair in dead condition. Set
has stopped working after a lightning,
Opened the back cover. Checked the
components at the SMPS [power supply regulator] board, as it might be most hit
by lightning. The 5Amp glass cartridge type fuse found burned and broken to pieces.
Some
other damaged component/s will be there.
It’s sure.
I
did measure the voltage across the main filter capacitor [C628] 120MFD 450VDC;
to check whether there is any residual static charge retains; because, if there is any
voltage, my multi-meter will get damaged, when I try to measure the DC
resistance across it. If there is any
static voltage, we must fully discharge it before we measure resistance across its terminals.
No
such static voltages detected.
I
set the multi-meter to measure Ohms, and did measure the resistance across the
main filter capacitor, mentioned above. I've attached photo of the SMPS board here.
The
result was abnormal. Measured only less
than one Ohms. There is a short circuit,
at the mains rectifier section circuit itself.
Un-screwed
out the SMPS board, to check which component/s are shorted / damaged.
(In
this condition, the only way to check is by de-solder out the suspected
component/s from the circuit board, and check it.]
I
de-soldered out the mains rectifier stalk [marked here the position of
it at
the SMPS board]; and checked its DC resistance. It revealed that it has
shorted junction inside; measuring a DC resistance less than 1 Ohms
between its
(+ve and (–ve) terminals. It has been
damaged. A voltage spike caused by
lightning has damaged it; dead short, causing the AC mains protection fuse to break into
pieces.
Now
it is sure that there will more damaged components. Without the rectifier stalk on board, I did
measure the DC resistance across the mains filter capacitor; mentioned
above. No short circuit detected now.
Checked
the mains filter capacitor out from the circuit for it capacitance; using
capacitance meter. It was OK. Measured 132MFD. Yet, it will be best to replace it with a new
one, because it has already been hit by a high voltage spike. Even if it will work right now, might cause
trouble with time.
Replaced
the main rectifier stalk, and the mains filter capacitor. Double checked the circuit and made sure that
there is no more short circuit.
Plugged
the set to AC mains wall socket, and switched it ON.
I didn't heard any ‘relay click’ as this model sets will produce normally during
power ON.
Checked
the DC voltage across the mains filter capacitor again, and found normal as it should
be.
On
further checking, one among the three opto-couplers used was damaged {part
number marked on board is PC803 (PC123)]. Its
LED side open.
Replaced
both the opto-couplers PC803 & PC801.
Both are of same number (PC123).
Now
switched on the set. OK.
There
was no other fault with its main board.
THE ORIGINAL REMOTE CONTROL NUMBER TO THIS SET IS
N2QAYB 000399
PICTURE AFTER REPAIR
Universal remote control set- up codes to Panasonic are:
0016 0032 0033 0049 0054 0075
0099 0101 0104 0107 0110 0119 0143 0151 0152 0161 0166 0207 0249 0304 0305 0306
0396 0420 0461 0611 0631 0633 0692
