Sharp Aquos LC-46XD1E no power-up

[marco1000]

Re: Sharp Aquos LC-46XD1E no power-up

I've already checked elektrotanya, and that 6MB file is strictly the few pages of schematics from the service manual, all with the exception of the (cursed) inverter boards.

There *IS* a return line from the inverter to the main board. It's on pin 5 of the 9-pin "LB" connector. In the block-diagram for the inverter controller, you can see that it has a "FAIL" pin, that's pulled up through a resistor. I measured that LB pin 5 today, and it sits around 1.35v at stand-by, and my multimeter caught a maximum of 2.8v before the relay clicked off and it entered that two-red-flash protection mode.

The inverter is made up of four boards. Board 1 (top left, seen from the back of the tv) has two transformers and six lamp connectors, board 2 (lower left) has three trafos and six lamp connectors, and also contains the inverter controller. Board 3 (top right)similar to board 1, but with three trafos and six lamp connectors, and board 4 (lower right) is nearly identical to board 2 (as in, it has two pairs of switching FETs, but it gets the signals from board 2).

I'm attaching a "stitched-together" simplified schematic of the inverter boards 1-2, as well as a couple of shots of the actual thing, including two shots of the solder side of board 2 (with the controller).

Hello everybody am trying to fix this sharp shown above by Khron666 it have the problem of motherboard of PSC10189dm PKG1 which does not release the current to the screen and the lights does not light up. Am not able to upload the picture because am new on this forum but if somebody know something plz reply thank you.

[Khron]

Re: Sharp Aquos LC-46XD1E no power-up

https://www.badcaps.net/forum/showpo...0&postcount=19

In other words, check the voltages at the outputs of all the regulators that you can, as a first step.

[FindTheShort]

Re: Sharp Aquos LC-46XD1E no power-up

I got a cheap SHARP LC46XD1E from ebay. Refurb it and turned it on, all worked, very happy. Then as usual, I tried to measure inverter output with a DMM, 5mm long plasma jumped out of the secondary inverter coil to the meter probe, then everything went kaput! Maybe some lights blinked, but I kept pressing the power button and didn't see it. Relay clicked for 1 second and off again.

P-CH MOSFET Q7403 on the #2 inverter board (out of 4), was shorted out.

1. Replaced the shorted MOSFET, still not working!
2. Downloaded the service manual, some voltages on LA, PL, PA, PB, PC turned on at STAND BY, some were simulated to turn on. Therefore, I assumed all regulators on the power board were ok.
3. Replaced all 4 inverter boards, still not working!
4. Replaced the power board, just in case, still not working!
5. During the relay clicked for 1 secend, on the power board, PB pin 6 (power error POWER_ERR) line has 3.3V. It should have 0V due to Q739.
6. At the same time, PB pin 8 (TCON board 12V trigger LCD_POW) has 0V. This signal directly comes from the CPU/FPGA. So, I suspected the main board was faulty.
7. While reading how to perform a hard reset procedure, I came across the Adjustment Process Mode. The precedures to get in/out of it are as follow:

1. Press the "POWER" key on the set of running TV set to force off the power.
2. While holding down the "VOL(-)" and "MENU" keys on the set at once, Press the "POWER" key on the set
to turn on the power. The letter "K" appears on the screen.
3. Next, hold down the "VOL(-)" and "P(V)" keys on the set at once.
Multiple lines of orange characters appearing on the screen indicate that the set is now in the
adjustment Process mode. If you fail to enter the adjustment process mode (the display is the same as
normal startup), retry the procedure.
4. To exit the adjustment process mode after the adjustment is done, unplug the AC power cord to force off
the power. (When the power is turned off with the remote controller, once unplug the AC power cord and
plug it in again. In this case, wait 10 seconds or so before plugging.)
5. To remove "K" mode, just repeat step1 and 2. This time the letter "K" disappears from screen.

In the Adjustment Process Mode, I saw 5 lamp errors under INFO (1b LAMP ERROR some hours and mins here), went to ETC menu, and reset the lamp error count (L ERR RESET) from 5 to 0.

TV turns on with no more 1 second relay click. It's fixed!!! In this case, it should have only cost me a P-CH MOSFET Q7403 and F7401 on the #2 inverter board, but I didn't know. So, I ended up buying all 4 inverter boads + power board. Lucky didn't buy the main board! Hope this helps you.