Sticky knobs

Spin Dr.

Main tuning knob of the "PRO" series radios.

(also applies to the original 756)

Been wondering how that knob comes off ? Where is the set-screw hole? I had wondered the same thing.

Japanese radios are notorious for lack of lubrication of the "VFO"/Encoder shafts.

However, you must be careful removing them. Prior to the "PRO" series ICOM radios, the main tuning knob was held on by a set-screw, which could be found after removing the rubber finger ring on the edge of the knob, simple enough.

The "PRO" series (& 756) don't have the hole. So, how is the knob held on the shaft? I studied the problem for several days, closely examining the service manual for any hint of how this was done.

I finally decided that the knob was held on by nothing more than the tension of a spring of some type.

I grasped the main tuning knob firmly, and pulled it straight off the shaft. Sure enough, the flat spot on the shaft was gripped by a small bent piece of spring steel.

There is a smooth "brake" surface on the back-side of the knob, this is rubbed by the "brake felt pad", and tension it adjusted by the small Phillips-head screw to the lower right hand side of the tuning knob.

If your knob seems to not spin freely, even with minimum tension applied by the brake, the shaft may need lubrication. Below is the procedure.

Turn the shaft until the "keeper-ring opening" (visible beyond the brake pad) points up, then place a single drop of high grade, FINE Teflon® based machine oil there on the opening in the keeper-ring. Next, place a few smaller drops around the felt surface of the brake-pad. Next, press the knob back into position, careful not to push too hard. Now, spin the knob vigorously for several seconds after re-installing it.

You're done!

If this does not relieve the spin "binding", you may need to send the radio to ICOM for Encoder replacement. It may have sustained shipping damage, or lack of lubrication on that shaft may have come to the point of metal-to-metal fusing, or seizing. This is irreversible, and requires Encoder replacement.

DO NOT over lubricate!!! One small drop of oil on the shaft every 5 years, only! Over-lubrication, will cause excess oil to migrate into the Encoder, and find its way into the optics, ruining the unit.

If your having a "spin" problem, and one drop of oil does not fix it, you should have the Encoder replaced.

I hope this helps.