[morzh]

Tom

You see why I asked then.
The 1st field coil in this radio is a filter/dropout, the second is a load. Insufficient load will increase the voltage.
If I read the parts list correctly, both fields are 3200 ohms, so your voltage roughly divides by two after them. I do not know if they are the same though.
Make sure you check the voltage at the specified Mains voltage from Variac.

Also about that cap.
The first cap is specified as 6uF for a single speaker and 8uF for the dual.
So, two things.

1. You do not have to have that extra resistor instead of the missing field coild. The reason the cap was increased to 8uF was to compensate for that extra load, but you do not have it if you do not parallel that resistor, and so you can revert to 6uF.
2. If you have 10uF you increase the voltage further so it very well might be the reason behind that 4 to 7V you are having.

So, what I would do:

Take off that resistor and make the first (#50) cap 6uF. This way you also do not dissipate a few extra watts and wearing the xfmr and rectifier out.
If you want 8uF, keep that resistor.