Knight KG-652 RF Sweep Generator Repair Journal
By Chad Hauris, Retro
Electronics and Audio Lab, Midland, TX. 6/18/2006
This RF generator was kindly given to us by a man in Odessa. We did
some preventive maintenance by replacing old capacitors and diodes and
adding a fuse to the power line before putting it into service. This
unit generates an FM signal by using an inductor that is mechanically
coupled to a speaker cone which is fed with a 60 hz signal.
When the speaker cone vibrates it moves the inductor which causes the
RF carrier to deviate at a 60 hz. rate from its center frequency. This
signal will thus produce a 60 hz. tone in an FM receiver. It comes in
very handy for troubleshooting FM IF transformer problems when the
generator is set to the FM IF frequency of 10.7 mhz.
Please click the pictures for larger views.
Chassis view. You can see the speaker modulator setup at the left.
Chassis before repairs.
Chassis after repairs with new capacitors and fuse.
Completed unit.
Testing a Silvertone radio chassis with the Knight generator (at top).
You can also see at bottom our Heathkit FM stereo generator and
Triplett AM generator. Using the Knight FM generator, we found a bad IF
can in this Silvertone in less than 20 minutes.
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