LDM
This video shows the teardown and reverse engineering of a vintage Radar Tuner TN-131/APR-9.
00:00 - Intro
01:00 - Teardown
02:08 - Input filter
06:08 - FI preamplifier
08:00 - Mixer
10:48 - Servo control feedback potentiometer and reflector voltage setting
13:52 - Motor
15:38 - Frequency setting test
16:34 - Schematic diagram
Technical description:
It uses a 1N26 mixer diode and a 2K48 reflex klystron for the local oscillator. Frequency setting uses a DC motor and several devices linked to the output shaft:
A fixed cam permits to modify the frequency of the reflex klystron.
An adjustable cam permits to change the central frequency of the input filter
A potentiometer permits to change the reflector voltage of the klystron according to the frequency
Another potentiometer is connected to the connector, probably for the servo control of the frequency setting mechanism.
A synchro transmitter
An internal indication of the frequency using coding wheels
Links:
Klystron 2K48:
http://lampes-et-tubes.info/mwkl/2K48...
Recorded 2023/10/31