Likely they did nuttin other than a normal check out for actual
failure... The problem is often with TRACON receivers not the
transponder... In my locality there is an area about five miles across
where many aircraft are told they need to reset their transponder...
Having flown this area for decades, when told that by the controller
while near this area I simply reply, "roger that 5 7 pop", and do
nothing... Sure enough 3 or 4 miles later he informs me "Mode C
received"... I reply, "roger that 5 7 pop"...


denny