[Red to black]

If you really do suspect a service mode mis adjustment error you could replace the eeprom with a new blank one, the u proccessor will detect this and attempt to program the blank eeprom with default data as a starting point, but I would need to look up first to see if you need a specific TTmode, service mode 2 and then see how to set it to uk standard first as well.

At least this gives you the opportunity to keep the orginal software safe, I thought I had a copy of this sets default UK software already saved but I couldn't find it on this PC.

I repaired loads of this series of sets about 15 years ago, a lot of the 36" versions too, but have no spares and very little left now from this timeframe.

I may PM you tomorrow RE: tech info

Edit: please don't attempt to factory reset the existing eeprom in the TT modes as you will lose all of the existing options and data settings, use a new blank eeprom of the same capacity in the set if you go down this route