I was having trouble with terminal controllers reading mode C so I pulled the transponder and encoder (ACK A-30) and shopped around for a price to see whats wrong...
the local avionics shop quoted $90 to look and a minimum of $90 x 2 if they had to do anything other than look) $270 + parts plus more labour so I continued to shop.
I found a fellow (recommended to me by friends at the Springfield Flying Club) that works in a shop for a small commuter Co. said he would give me a free estimate; sounded like a good deal.
He called and told me that mode C does work, problem is with the transponder on the receive side not the encoder; it can't hear an interrogation from more than about 10 miles so it won't respond (mode A works fine ?).
He estimates 4 or 5 hours at $80/hr plus parts to repair..
What now?
Looks to me like a $500 -
? bill to repair the Collins. I plan a panel upgrade in a few years (not now 
) and would like to get a transponder with mode C (mandatory in most of my area) and am torn, do I leave it and stay out of terminal areas for a few years or throw money at the Collins to fix it, or replace it?
