AH-4 tuner problems

[sloop]

My AH-4 tuner quit working. It worked two days ago but has now decided not to tune the antenna. Power from transmitter to tuner is ok and transmitter is transmitting. The unit was installed in the attic so weather exposure should not be the problem. Anyone have any suggestions?

 

[prcguy]

Had any close by lightning strikes lately? I had lightning take out at least four SGC auto tuners and these were not direct hits but just close ones in the neighborhood. A nearby strike can induce lots of voltage on the wire that can take out diodes in the forward or reverse VSWR sensing circuits. Or the AH-4 could have simply died of old age.

My AH-4 tuner quit working. It worked two days ago but has now decided not to tune the antenna. Power from transmitter to tuner is ok and transmitter is transmitting. The unit was installed in the attic so weather exposure should not be the problem. Anyone have any suggestions?

 

[AK9R]

Have you measured the voltage at the AH-4? If you are using a control cable that follows the Icom standard, the red wire should be approximately 13 volts DC when the connected radio is turned on and the black wire should be ground.

I have had multiple occurrences of furry little critters eating through my AH-4 control cables. In one occurrence, the tuner just wouldn't tune because one or more of the wires in the cable were eaten through. In another occurrence, two of the wires shorted together which caused an internal 5 amp fuse to blow inside my IC-7610.