I'm not sure why this thread is even being cross-posted into a CB group,
but
to answer your question, in the US, the radio must be serviced by a
qualified, licensed individual. That is the "legal" way of doing it
anyway.
It doesn't happen very often, but that is another story for another
time...



Get a new rule book like one that is newer than say about 10 or so years.
The CB radios in the US has not required a license to repair them in many
years. The GROL is the replacement for the 1st and 2 nd class licenses that
used to be required to repair many transmitters. For about 95 % of the
transmitters in the US it is now worthless and not needed. Some companies
may require it as they think they are getting someone that may know
something. Now it is only needed for :

*****************
General Radiotelephone Operator License (GROL) is required to adjust
maintain, or internally repair FCC licensed radiotelephone transmitters in
the aviation, maritime and international fixed public radio services. It
conveys all of the operating authority of the MROP.

It is required to operate the following:

any maritime land radio station or compulsorily equipped ship radiotelephone
station operating with more than 1500 watts of peak envelope power;


voluntarily equipped ship and aeronautical (including aircraft) stations
with more than 1000 watts of peak envelope power

********************

Go here for more info on the licenses that are now issued.

http://www.narte.org/h/fccabout.asp