sizing problem tv decca d28wt92s

[martynl]

decca tv d28wt92s has developed a sizing fault.
initially there was pincushioning at the sides of a 4:3 image but 16:9 was ok.
Then at power on the picture would flash on/off for abut 15 seconds and then come on but all aspect ratios show pincushion at sides and picture is way over-sized and dim.
Have now replaced with LCD TV but want to know if worth fixing for use in another room.
Any help welcome.

Martyn