[Hallicrafters] A SX-24/SX-25 queston

[kirklandb at sympatico.ca]

Both the SX-24 and 25 have some trimmer caps within the chassis which are not addressed in the IF/RF tune up.
E.g.  on the SX-25 schematic, C18 is shown as a compensating capacitor (in parallel with a resistor).

Any idea what these are doing and how to adjust them ?  (They are set in such away as to hinder adjustment - hmmm might be a hint).

bill, ve3jhu