Got the schematic.
measured the voltages around IC 301 TDA 8178S, All seems Ok except pin
3, with about 12v, (1.4v on schematic) and pin 5 with about 18v.
(13.8v)

Already changed c304 103k, 25v rectifier D301 1n4001. I had previously
changed C308 2200UF and C310 220UF, no change.

Before I fit the new IC, I would like to rule out the possibility of
something amiss on the circuit. Something does not seem right with
those voltages, but I don't know if it is caused by :
a) faulty TDA8178S IC (leaky)
b) misprint on schematic
c) the fact the ic fitted - tda8178s - differs from that specified on
schematic (tda 8170)
d) some problem in the vertical (frame) circuit

Any advice gratefully received. I am currently trying to upload the
extract form the schematic, will post link here when I do.