A friend just let me know that his relatively new (four year old) Bendix
King KT76C transponder failed the mode C biennial test.

When the unit was sent in for a $250 troubleshooting (Duncan, I believe,
not Honeywell) analysis, he was told that his unit required a $1,700 repair
to replace the failed "tube" inside.

It looks as if a used KT76C is selling these days for US $1,700 to &1,900.
Does he really have no option but to throw this thing in the garbage?

--
Peter