Zenith AM/FM Radio K725

After rebuilding successfully a Zenith FM/AM radio for Maguette I thought about to have a similar radio as a gift for Maguette's girl friend Heidi. I got an AC portable from 1950 with AM and FM bands. I hunted on ebay, and got a Bakelit case model for US $46. It was supposed to work. I guess it is a model K725.

The Zenith AM/FM Radio tube complement consists of:

Chassis number is 7G01.

I've found a similar schematic of the 7G01Z1 chassis, with a 35C5 in place of the 35B5, and 2 x 6BJ6 in place of 2 x 12BA6: Zenith_7G01 (168k)

According to the G number it is a model of 1950.

The radio works. I'm replaced a lot of caps and checked the resistors. The selen rectifier, which was becoming really hot, is replaced with a BY 500/800 diode. I've used a similar diode in one of the AC phases to make the radio ready for 230V AC. Because of this changes the B+ voltage went massively to high, so I used a 470 ohm 25W power resistor to drop down B+ voltage. Also the 80µF section of the multisection electrolytic power supply cap was replaced, and some of the 'usual caps' (grid cap of the power tube etc.).

The bakelit case is polished:	The chassis with the antenna on the back. On the left side of the chassis is the variable air capacitor construction.	A view under the chassis. Close to loudspeaker you can see the golden alu housed resistor at the place where originally the selen rectifier was.

The bakelit enclosure, with some cracks, was glued and polished. For the pilot light I've used a small glow lamp with a resistor ready to connect to 230V AC. The radio is now ready to run. It left my home heading to Heidi ;-)

Reception of the Zenith 7G01 is really good, not in the same excellent way like the more complex Zenith Y832 model, but much better than a lot of German FM radios from the 50ties.