27lcdb03b does not turn on - LG 50PX4D 50 in. Plasma Television

Turn Signal Lamps
The STOP/TURN/HAZARD fuse in the instrument panel (I/P) fuse block supplies battery positive voltage to the body control module (BCM) for the turn signal lamps. When the turn switch is placed in the LEFT TURN or RIGHT TURN position, ground is applied from G202 through the turn switch, to the turn signal switch signal circuit and to the BCM. The BCM then applies battery positive voltage to front and rear turn signal lamps supply voltage circuits. The left front turn signal lamp is grounded at G100, right front at G101, left rear at G301 and the right rear is at G302.

Turn Signal Reminder
The driver information center (DIC) activates the turn signal warning as requested by either turn signal switch. The turn signal warning sounds when the following occurs:
• The ignition is in RUN.
• The turn signal switch is in either turn position, sensing, within 1 second, an open to battery positive voltage transition in the turn signal control circuit, left or right turn.
• The vehicle has traveled a distance of 1.2 km (0.75 mi) by counting pulses in the rolling odometer class 2 message.
The DIC turns OFF the turn signal reminder when either the ignition switch is turned to the OFF position, or the turn signal switch returns to the OFF position, sensing within 1 second, no transitions from open to battery positive voltage in either of the turn signal control circuits, left turn or right turn.

My first step would be to hook up a factory scan tool an check for DTC'S - diagnostic trouble codes

DTC B3948 Left Front Turn Signal Circuit
Circuit Description
Ground is applied to the turn signal switch. When the turn signal switch is placed in the turn left position, ground is applied to the body control module (BCM) through the left turn signal switch circuit. The BCM then applies a pulsating voltage to the LF and LR turn signal lamps through the LF and LR turn signal voltage supply circuits.

What's the left rear lamp doing ? Flashing fast ?

DTC B3950 Left Rear Turn Signal Circuit

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What fuse are you pulling ?

Hazard Lamps
The hazard warning switch is part of the turn signal switch. The turn signal switch receives battery voltage at all times through the HAZARD SWITCH Fuse. When the hazard switch is placed in the HAZARD position, battery voltage is applied to the hazard lamp/turn signal lamp flasher. The hazard lamp/turn signal lamp flasher sends a turn signal flasher signal to the turn signal switch. The turn signal switch provides all of the turn lamps and turn indicators with the turn signal flasher signal, simultaneously flashing them on and off.

Turn Signal Lamps
The front turn signal lamps are made up of the front park/turn signal lamps and rear turn signal lamps. The front turn signal lamps flash with the rear turn signal lamps when a turn is initiated using the turn signal/multifunction lever. The turn signals will operate only with the ignition switch in the RUN position and will not operate during hazard flasher operation.
When the ignition is turned to the RUN position, battery voltage is supplied to the TURN SIGNAL Fuse. Battery voltage is then applied through the turn signal fuse circuit to the turn signal switch. When the turn signal switch is placed in the LH or RH position, voltage is supplied to the hazard lamp/turn signal lamp flasher. The hazard lamp/turn signal lamp flasher supplies a turn signal flasher signal to the turn signal switch. With the turn signal switch in the LH or RH position the corresponding turn signal indicator, rear turn signal, and front turn signal receive the turn signal switch signal and will flash. The front turn signals receive the turn signal switch signal from the turn signal switch via the BCM. The turn lamps are permanently grounded.

Replace the turn signal switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column - Tilt.

I would suspect main board more than one you replaced--not likely to get help as Thompson is not known for that--possible firmware upgrade seems likely.

On every set I have seen with upside down/inverted or reversed screen etc it has been either a firmware issue or a main board.

does the power light change when you try and power up.
try www.tvs-services.com they may have a kit for this model which must be fitted by an engineer

Hello Chris, Hi, your TV's power supply section is not functioning properly. If the fuse is in good shape, then the auxiliary power section of the power supply is not functioning, this section powers the switching oscillator and IC that sends the pulse to the switching element like power transistors to create a main secondary voltage. the main secondary voltage is the circuit that produces all voltage needed source by the TV. what you can do if you are up to it.
A. Visualize any bulging capacitors, replace them. B. Measure the voltage across the following section in particular order so we can find the faulty parts.

1. the AC input on the Power supply board. (none means open switch or power cable)
2. the AC after the line filter circuit. (none means open line filter)
3. the DC on the filter capacitor. (none means problem on the rectifier)
4. then the AC on the switching element or input on the main transformer. (most likely you won't have any voltage reading hear.)if you do have continue.... (none means you scratch your head, this is the hardest part) check all low value resistors, high wattage resistors open or shorted diodes.
5. the dc on the secondary filter capacitors.

If not have this checked by a technician, its to complicated for you.

as i am not very good on computers i could only go so far i was not getting the ansers i wanted so i rang a tv man from my local phone book he came and it is a fault with the remote control so orded a new one thank for your enquirey regards brian 298

CALL 01245392539 AND THE UK THOMSON SUPPLIER WILL BE ABLE TO TELL YOU IF IT IS STILL AVAILABLE

If all the voltages measure normal, the failure could be in the LCD's inverter board. I've checked the schematic and it seems like the 16 volts could be a bit higher, check the electrolytic capacitors filtering the voltage for the inverter board.
Click here to download the service manual.
Good Luck.

cannot be presise but at worse the lcd back light is failing or the supply to it . this is a job for a service engineer