The International Cessna^® 170 Association

Are there members who have the latest ICOM (210) radio? If so do you also have a second com/nav-com used in connection with the 210? In my setup I have a 210 & 200 with a King audio panel and a Sigtronics SPA 400 ICS. Initially upon the installation of these 4 components, when the 200 was set to transmit and the ptt was activated it would cause the 210 frequencies to flip/flop as if the flip/flop button on the 210 had been activated (pushed). If the 210 was selected to transmit and the ptt was activated it had no effect on the 200 (nor should it have). Wiring was checked for proper set up and found to be correct. A call to ICOM to discuss with their tech -------- and he said this was normal. I DON'T ACCEPT THIS! No way should transmitting on one com radio cause the frequency flip/flop on another com radio to flip IMHO. The 210 wiring schematic shows that there is one pin which is an interlock that prevents the 210 from receiving a transmission from another radio in the plane (the 200 in my case) when that radio (the 200) is transmitting. After researcing this we disconnected the interlock pin for the 210 and that solved the unwanted flipping of frequencies on the 210 when the 200 is transmitting. The 200 has such a interlock too, but transmitting on the 210 does not result in the flip/flop of frequencies on the 200. The only possible problem that may be occurring with this setup is that when certain frequencies are set into the 210 and certain ones are set in the 200 and we transmit on the 200, we get a lot of noise (carrier noise) on the 200 when flying, but not on the ground. This may not have anything to do with the interlock situation, but again may do so. Just curious if anyone with a 210 and a second com/nav-com have experienced this SNAFU????? There may be a problem internally with the 210

Frank, did you see the replies to your earlier query on this subject?

http://www.cessna170.org/forums/viewtop ... f=5&t=7335

To be honest I have had so many irons in the fire with these radios, etc. that I had forgotten I earlier asked the question. Sorry about that However, the only thing I have found that prevents the condition is to remove the "N" pin which is the interlock pin. While I have sent an email to ICOM to again get their "take" on the issue (hoping to get a different tech than before) and see if there is some possible pin arrangement that will solve the issue. While I have had many years of very successful service from ICOM radios, their tech support seems to be below par.