[TinCanAlley]

Originally Posted by old_tv_nut

The coils should not need adjustment unless you replace associated tuning capacitors.
Abrupt intermittent changes imply intermittent contact, solder, or potentiometer problems.
Color disappearing and coming back could be intermittent problems in the tuner.

Do not adjust coils until you have searched for the much more likely causes of intermittent behavior.

Only one coil is adjustable and I wasn't about to touch it as I believe it would require a sweep generator. I will focus on all the capacitors and resistors. When I inspected the board visually, I found no cracked solder joints or other abnormalities.

Question.... The SM has a resistance chart and IC903 on the Chroma board is there with readings for all legs. However, it doesn't state how to go about getting those readings. Do I leave the module plugged in and probe from chassis ground to each pin? Remove the board and probe from ground point on module to each leg? Do I remove the IC and problem from ground leg to all other legs?

I have a Hickok 246 arriving Friday. It does the keyed (gated) rainbow as well as a few others my Leader doesn't. It should allow me to verify correct APC adjustment via waveforms.