power suply oscilation

[zorgue]

I have a grundig mw70-2700 nic and don´t work bicause power suply at pin 7 of tda 4605-3 have litle oscilation (6v..9v).who i have eliminete these oscillaion?please i need your´s helps and sorry for my english,i´m portuguese and no speek english very well.thank´s.

[vtech]

Not familiar with the set, however looking at TDA4605, pin 7 is generally used as a soft start by means of short pulses.
While there are many causes that could prevent startups, In general suggest looking at any & all electrolytic caps around the IC that could easily cause no-start in ANY chopper supply application--any cap in the range of 1-100 microfarads that are around the primary circuit.