SA612AN PDF Spec Sheet
This kit is a very typical NE602 audio detector mixer circuit.
It includes a MUTE circuit consisting of Q1 and Q2.
Q1 is shown as a J201 but may be sub'ed as a J113
A positive voltage on the +MUTE signal line opens the audio signal path.
BFO oscillator injection is from a fundamental crystal tuned
via C5 or from an external BFO.
The 5.068 crystal is included.
C1 is now a 33uF cap. Note polarity when installing.
C2 & C10 are 330uF caps
C3 & C6 may be replaced with 47n capacitors
C9 has a 2.5 mm lead spacing; form leads to fit 5 mm holes