[ICOM] IC-765 Auto Tuner Problem-SOLVED

[David Hammond]

Hi Everyone,

Back on September 26th I posted a listing describing how my IC-765 had developed a problem with the auto-tuner where it would not find a match on 80 meters while working and matching perfectly on all other bands.

After receiving parts from ICOM, today I replaced the two 3.5 MHz relays in the auto-tuner along with the two HV supplemental capacitors that are switched into the circuit on the 80 meter band. Similar arrangements are also to be found for the 160 meter band as well.

Apparently one of these four components had failed as after the replacements were installed the auto tuner now matches on 80 meters once again perfectly. I cannot tell for sure but suspect the supplemental capacitor relay RL-2 as the culprit. The HV caps seems visually to be intact.

Problem solved.

So if your 765 tuner refuses to find a match on a single band and you rule out antenna problems, the problem most likely is in a relay in the auto tuner or in a failed HV capacitor.

These parts were still stocked by ICOM and relatively inexpensive. Lots of relays in this auto-tuner!

BTW he tuner removes as a module and the disassembly was relatively simple. 

You do need a service manual to make clearer work of this fix.

IMO this radio is one of the finest I have ever used.  Short on features (by 2005 standards) but way long on performance! 

73 de N1LQ-Dave