What could be the problem ??
Since it worked OK before, something has changed.
Double check all of your coax connections, and physical connections
in the antenna itself. (Loosened screws, loose hamtick element).
Have you had any really wet weather? Make sure water hasn't gotten into
anywhere it's not supposed to be.RF could be getting into the tuner?
But why now...who knows?
Have you tried changing the batteries?
Depends if he has the older discontinued metal enclosure
Z-11 QRP tuner (which does not take batteries) or the newer Z11ProII.
Like the man said, if you're using batteries, change them.
If you power it externally throw some chokes on the
DC power cable close to the tuner.
Check all the simple stuff first OM.
Good luck. 73, Ken AD6KA
NB: I have the Z-11 QRP Tuner (no longer made)http://www.ldgelectronics.com/c/252/products/7/30/3
Great tuner made SUPER by getting rid of the stock disc capacitors
and replacing them with Cornell Dubilier Silver Mica caps
of greater range in the tuning circuit. Also make a better
enclosure-to-PC Board ground for that tuner and
add a brass Ground screw at the back. There's a darn
hole already drilled there for one, LDG was just too lazy to add it.
If you have this version, Z-11 QRP, dont let them
try to sell you the $40 CPU upgrade,(Trade, really, they
want their $40 chip back,hihi. It's a waste of money.
Nice tuner once ya get the buga out. Runs to 30 watts they say, I've
run it past 50 watts.