Pretty sure it's the rear-most side of C79 that leads to pin 4 of IC2. Won't hurt to try just hooking the white wire there. DO NOT connect the white wire to the side of C79 connected to L19. We pull out the front lead of C79 and insert a 22pf cap in the pc board hole. The two 'flying' leads get soldered together and the white wire goes to that junction.
This makes the extra channels less affected by the setting of L19.
More than one way to skin a cat. Our interest is served by making sure it won't act up if it's operated mobile at low temperatures. More than one way of doing this will be fine at room temperatures only. And if it's a base that will never be operated mobile, who cares, anyway.
73
So your saying the existing cap at c79 is just fine just pull the side facing the front of the board add 22 to the hole tie to the other side of c79 add wire at that joint sounds straight forward enough I'll post results....