ADF Problem

"Mike Spera" wrote:

... Many of these units use discrete (individual) electronic
components, AND most of these units are quite old. Certain
capacitors in
these units shift their electronic values over time, causing changes
in
the circuitry's operation. Hence, they need to be realigned every
now
and then.

Per three ADF service manuals I have, there actually isn't any
alignment procedure to adjust pointer indication. You are correct in
that the installation may need trimmed out, but for example in one
ADF, you remove a mounting screw on the indicator unit and tweak
something with a supplied tool. In another, you loosen and physically
twist the goniometer (what magnetically makes the needle move). Those
adj. are worth only a few degrees, though.

If there's a combined loop/sense antenna, it may have active circuitry
inside which can also have a defective component, but it may not be
field repairable. However, cleanliness and security of the loop
antenna connections is one thing to check in any case. Beyond that,
some component(s) somewhere is likely defective if a 30-deg error.

Fred F.