Nr. 14335

The receiver's face-plate. It has been cosmetically restored before I started working with it.

Testing the RL12P35 transmitting pentode

Both transmitting tubes test out good.

Found one broken solder joint. Otherwise, the transmitter looked good.

Photo of some of the transmitter's electronics. Note the neatness with which the capacitors are numbered - almost like calligraphy.

Modulation stage transformers.

Socket for the RV12P4000 modulator tube.

Socket for the power amplifier tube.

The integrated capacitor container. 5 capacitors in one box. If one of them fails, the entire box needs to be "restored". Luckily for us, all capacitors were good and did not leak.

The vacuum tubes from the 10W.S.c

 

 

The RF oscillator tube connected in its socket.

The RF power amplifier tube connected in its socket.

 

 

Testing the output frequency of the oscillator circuit.

 

 

The test is being performed ate 27.2 MHz. Other tests were run at 30.0 MHz, and 33.3 MHz.

 

 

Close to perfect. The oscillator produces a carrier wave that oscillates at exactly 1/2 of the transmitted frequency. A frequency multiplication circuit doubles the frequency on its way to the power amplifier. 13.6265 MHz x 2 = 27.253 MHz, very close for a device that has not been tuned for over 64 years.

 

 

Tanking the face-plate off to reach the Ampere-meter for testing. I'm always amazed by the exquisite machining of these devices and the elaborate mechanics. Looks like the firm of SABA made this transmitter.

 

 

The reverse of the fully-functional Ampere-meter