Loewe Xelos A32 - backlight inverter excess current

[mattlumb]

HELP please - at a bit of a loss with this one!
TV dead apart from front LEDs - found blown fuse (4A) on PSU UB output (24V). Following replacement blew PSU primary FETs (etc.) following replacement (nice).
TV powers up and works normally if run from bench supply feeding 5V and 24V but 24V current into BL inverter is excessive - more than 6A.  All 8 backlight tubes are functioning, no part of the inverter (single board Taiyo Yuden KLS-S320BCI-M) warms up and all 4 push-pull stages have similar waveforms. No transformers warm up more than the others.  'lytics have good capacitance and ESR is fine.

Reducing the contrast reduces the current but between 16/20 and 20/20 current is the same and so is the contrast (seems odd).  Below 16/20 the inverter enters burst mode and modulates as expected in response to a burst PWM signal from the control board (from Atmel microcontroller).  The dc current from the 24V also drops a lot down to about 2A at lowest contrast.  This TV is marked 85W on the back so clearly the max. current into this inverter should be a lot less than 3A.  Standby current on 24V is about 0.6A. (14W stills seems a lot).
Here's the questions - there is a second control signal out of the micro with a 10uF ceramic capacitor on it (after a potential divider) so clearly not meant to be a PWM signal - mine is stuck at a dc level which doesn't change with picture settings - should it ?
Does the micro need flashing? (how?)

Many thanks in advance.

[mattlumb]

I went back to basics and realised I am looking at the wrong service manual.  DOH!
This TV is Art.Nr. 66418 (L2650 chassis).  The schematics I have show the same chassis no. but different article number with differnt PSU main rail voltage and a dual master/slave inverter boards.
Has anyone got the correct service manual for this Loewe Xelos A32 LCD, Art. Nr. 66418?
Many thanks in advance.

[Turnip]

Hi Matt,

Don't see many of these sets - could you attach some piccies, we might know it as a Technika - Chris.

[mattlumb]

Hi Chris,
Many thanks for your reply. Here's some pics and a clip from the service manual that I have which is for an earlier version of the A32 and the same chassis but a different model number (Article Number). I'll upload the service manual - it's 30MB.
The power supply is a bit different and the backlight inverter arrangement is completely different. I'd be really surprised if this turned out to be related to any budget brand - Loewe seems to be sold as a high-end German make. The inverter is definately taking too much current but nothing is getting hot and all stages have similar waveforms.  If run the backlight from a 3rd supply it works OK from 19-35V but still too much current (constant power i.e. turn the volts up, the current comes down).  Turning the contrast down below 16/20 it reduces the current and starts buzzing at 168Hz audibly both from the bench supply and through the speakers.  There are 2 signal lines from the signal board into the inverter, they come from connector W2032 pins 4 and 5 on the signal board and go into inputs on the inverter marked PDIM and DIM on the inverter. One signal doesn't change (DIM), the other is the 168Hz PWM for controlling the contrast (PDIM).  It's entirely possibly some numpty has put the wrong invter in this TV, or flashed the wrong sw version to the micro. Thanks in advance. Matt