dave wrote in
news:lUn%b.126184$jk2.539089@attbi_s53:

1. A weak transponder transmitter section. It works, but doesn't put
out the full rated power.

There are minimum requirements for passing the transponder power tests
one is power. This is rated on the class of the transponder.

True, but I do NOT see this being tested by avionics shops. Their antenna
is placed wherever they can, to get a signal. Sometimes that's several
feet away, and sometimes it's within a couple of inches of the transponder
antenna. I've NEVER seen an on-aircraft certification fail a transponder
that was still working for power. [I have seen bench tests fail one for
power, but that's virtually always because it was so weak that they
couldn't get it to work at all with the standard tarmac test set.