Realistic Portavision-150 5" color tv

[MrPiggy]

Hi guys
I am trying to source a schematic for this 5" colour set. Possibly a Tandy/Radio Shack variant??
The hor hold was off when I switched on after receiving in the mail. I adj it for a good lock and was fine all day with cover off. I replaced the cover and turned on again and within 10mins the hor hold had drifted again. So I assume its a heat related issue? Capacitor maybe?
Anyway I took it to bits and noticed a burned out resistor. R702. I am wandering if this has anything to do with the fault? It is burned badly and therefore colour code has gone. I need to try and get a circuit for this chassis.
I have included a few pics in case anyone recognises it as being used in other sets? I cannot find any info on this set at all sigh!! Many thanks for any help.
Terry