[ICOM] IC 765 Tuner Issue

[Gary Fiber]

Nate,

This was written by the tech who used to do most of the IC-765 work 
when he and I worked at Icom America. This is from the Icom America 
web page Knowledge Base under model 765.


Knowledge Base Article 5BBA692A36

Issue
The tuner on my 765 does not tune on any band. Inspection reveals 
that only one motor is turning.

Resolution
The motor gear assembly is jammed at one end of its tuning range. 
This failure is usually caused by an attempt to tune an excessively 
high-SWR load.

To fix:
Disconnect J6 connector on tuner unit and momentarily apply a DC 
voltage (around 15 volts) to the stuck motor to un-jam it. Reverse 
the polarity of the voltage to the motor if it doesn't unstick the 
first time. Reconnect J6 connector and test the tuner. It should now 
work fine. If it does not, the motor driver chip (IC2) has probably failed.

Gary K8IZ



At 06:09 PM 11/9/2009, you wrote:
>I believe a servo motor in my IC 765 is jammed. I read a procedure 
>in which a voltage of 15 volts can be applied to the motor to un-jam 
>it. Does anyone have experience with this?
>
>The procedure mentioned seemed to be lacking details. It said to 
>remove jumper J6 from the tuner board and apply 15 volts to the 
>motor. Do I apply it directly to the motor or are the leads to the 
>motor on the jumper?
>
>
>Is there another alternative?
>
>
>73,
>
>Nate/N4YDU
>----
>Your Moderator: Dick Flanagan K7VC: icom-owner at mailman.qth.net
>Icom Users Net: Sundays, 1700Z, 14.316 MHz
>Icom FAQ: http://www.qsl.net/icom/
>To support QSL/QTH.net: http://www.qsl.net/donate.html

Gary Fiber K8IZ
GROL PG-19-6691
Washington State Resident