klem kedidelhopper wrote:
On Mar 11, 3:56 pm, wrote:

(...)

Were it me, I would move on to other things.

If the radio repeats the symptoms, then it wasn't an
intermittently leaky C38. At that point, I would
open the investigation once more.

Hey, it's working. Be happy.

(...)

So I've replaced all the original transistors, resoldered the
transistor cans, (grounds) and reset the bias with R22 to -1.18V with
7.50V applied to the battery connector. That bias voltage however
rises to -1.33V when the supply is boosted up to 9.0V. So as I
expected, it seems that the supply voltage does make a small
difference in bias. Does anyone else have any theories as to what
Grundig may have had in mind when they specified that bias as well as
the other circuit voltages? Was it with 7.50V applied or 9.0V? Lenny

The way I read Grundig's schematic notes, they want us to set the
lab supply so that 7.0 V is seen on the power rail if in 'Medium Wave'
mode or 6.75 V on the rail if in 'FM' mode.

If that requires 7.8 V on the actual battery connector or 12.7 V
on the actual battery connector, it does not matter as long as the
rail voltage is set correctly for the function chosen.

They want the radio to function well with brand new batteries or
almost dead batteries.

I would not sweat over bias drift when a real battery is connected.
The documentation is pretty clear on their requirement.

--Winston