Swan 350 Crystal Calibrator

The crystal calibrator was an option in the Swan 350. It was available either as a factory installed option or in kit form for user installation. Factory drilled holes were provided in the chassis for later installation.

Do I have One Already?

There was no externally visible indication when the crystal calibrator was installed. Just pull (gently) on the RF GAIN knob. If it has a push-pull switch operation then the calibrator is installed. Pull=ON, Push=OFF.

Internally you can see the 12BA6 tube installed in socket V17 (located behind V6 and V7).

If not installed you can see the pre-cut holes where it belongs (10 holes of various sizes).

Do-It-Yourself Crystal Calibrator.

Of course, the kit is no longer available but you can build one yourself if you can find the parts that mount in the existing holes. Sorry but no more specific parts info is available.

PARTS LIST

27k resistor
100k resistor
1meg resistor
150 pf disk capacitor
5-80 pf trimmer capacitor
100 khz crystal
crystal socket
12BA6 tube
9-pin minature tube socket
10k pot with push/pull switch (Pull=ON)

Notes:

A. Output coupling capacitor (shown dotted) is insulated wire loosly wrapped around the lead connected to V6 pin 1

B. S2 is a push-pull switch on a replacement RF GAIN pot.

C. Connect V17 pin 3 to V7 pin 3 (12.6v heater lead) and V17 pin 4 to ground.