ICOM IC-M710RT Tune Problem

[barney1964]

Dear all,
we have diagnosed the fault in that the antenna tuning unit (Icom ATU 130) will not tune with the transmitter (the black box). When I have a friend's transmitter installed, it tunes, relays rattle through all sorts of frequency changes.
We have checked the switches inside the transmitter are correct for the AT-130 tuner (which was replaced last month based upon the diagnosis of the professional technician who believed he had found the problem).... We have also checked the quad (controller) cable, insulators etc, grounds etc.
As said earlier, it works with another (older) transmitter in - the relays click correctly.
Does anyone have any ideas on what may be further tested within the transmitter box, and whether or not it's worth getting professionally attended to, or to get a new one. Age of the unit is circa 17 years.
Thank you in anticipation.

[daddle]

For me it is always that ten cent el-cheapo quad connector on the transmitter. Finally cut it off and used a terminal block.

[barney1964]

Thank you Marinduque. We certainly found one of the wires was corroded and have tidied this up, including using a connector whilst undergoing the diagnosis.

Don't forget, it works properly when our buddy's transmitter is installed!!

[belizesailor]

I had the power lead to the control head cause issues for me last year. A bit of corrosion was enough to make the unit misbehave. I would check and clean all connections, not just those to the tuner.

[transmitterdan]

Is your transmitter actually transmitting? One necessary condition for tune is low power RF which allows the ATU to select the right tuning setup. No RF and it can't tune.

The only other thing it needs is the signal from the radio saying "ok to tune". I would suspect a bad connection at the radio (black box) assuming you used your cable with your friend's radio.

[rjgunther]

You really need a watt meter or an VSWR meter to troubleshoot this problem.
They are available relatively cheap at any ham radio store, or even radio shack.
Bob NM1Z