[Boatanchors] Roller inductor cleaning

[Ian Wilson]

I'm putting the HF section of a GO-9 on the air. Last night was the first
time that I've had a chance to do any testing on the PA section (the MO and
IA appear to be working well so far).

While tuning the PA (with *very* reduced voltage on the plate), it became
obvious that the (two) roller inductors are making intermittent contact. I
have used similar techniques to clean them that have worked successfully on
ARC-5 roller inductors - i.e. a toothbrush with a slurry of BarKeeper's
Friend, followed by wiping off any residue with damp paper towels, and
drying well. The inductor wires are now a nice clear silver.

Have also cleaned the slider bars and the roller wheels, but these are still
somewhat discolored. These appear not to be silvered, rather some sort of
brass or other copper alloy. Suggestions for how best to clean these?

I don't think I can dismantle the inductors, so have to work with what I can
see of them.

When tuning, I could see some arcing between the roller wheel and the
inductor itself, so it may be that most of the problem lies with the wheel.

The spring mechanism that applies pressure to hold the wheel to the inductor
appears to be weak on the PA roller inductor. The springs may have weakened
over the years. Ideas for how to stiffen this up would be welcome.

Thanks for any help.

73, ian K3IMW