You need the transponder check even for VFR. I suspect he's close enough
to the class B to require it.

If he's in Class B, he's definitely screwed without a transponder.

However, it's not broken -- he's missing a piece of paperwork. If the thing
is working (and, as I said, ATC will let you know if something is amiss),
make an appointment to get the thing checked, and go fly.

A transponder is hardly a flight-critical instrument.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"