Just got hold of a 1970s JJ Beolit 600.

It has a weird problem in that it powers up, and a feint hiss can be heard on both FM and LW bands. On the MW band there is full volume when the tuning slider is between 1200-1400 (there are no stations I can pick up in this range) and there is very weak volume on all stations either side of the 1200-1400 range.

Any ideas what's wrong?

John 

If this is a mains powered radio, check the power supply for cracked solders. It's very common to see, especially at the transistor with the long cooling fin. The power supply is in the metal can, metal lid held by one screw.

Needless to say; unplug from mains before going in there.

Martin

Hi Martin

I'm running this off 5 D cell batteries. There had been a previous leak in the battery compartment that had corroded the negative terminal that slides back and forth. I've cleaned it up after a fashion, and the multimeter shows DC current going in to the set.

Does this shed any light on things? 

I suppose we can rule out a power problem then unless the voltage on the main board is off.

Check the main board for signs of broken tracks, damaged corners etc.

Maybe someone tweaked the coils ...

Martin

Just looking at the board - everything looks ok and intact.

Could I 'untweak' the coils, or does this need to visit a repair shop? 

Don't tweak anything unless you are absolutely sure its needed. Trial and error won't get the tuning correct

If the supply voltage to the board is correct (battery voltage), there's really not much you can do without more advanced instruments.

Maybe it has a blown IF transistor or something like that. Sounds to me like a job for Tim...

Martin