I think you would be better to throw it away and buy a good quality radio. I suspect it will be difficult to locate the problem and to get replacement parts. I can't find any service information for that model number. Once we know the voltages on those pins, we may be able to narrow down the area of the problem. If pin 1 is 0.8V or higher, you can safely bridge it to the 0V rail and see whether that makes the amplifier start working.
My guess is that pin 1 needs to be low (between 0.0V and 0.5V) for the amplifier to operate, and if it's higher than about 0.8V, the amplifier will shut down and go silent. I'm not sure what that voltage should be, because the data sheet doesn't explain it, and uses conflicting names for the pin. Pin 1 must also have the correct voltage. It must be between 2.2V and 5.25V, according to the NS4148 data sheet. Pin 6 of each NS4148 should have the supply voltage on it. If it's a manual ranging meter, set it to the 20V range. Then measure some voltages on both NS4148s with your multimeter set to DC volts. Find a place where you can make good contact with a multimeter probe, and keep your multimeter's black probe connected to that point. It will connect to some large copper areas. Follow the track from pin 7 of either of the NS4148s. First, find a good connection point for the circuitry's 0V rail.
I found a data sheet it's in Chinese, but the important information is there.
OK, the amplifiers are type NS4148, made by 'Nsiway'.
