[R-390] R-390 Oldham Springs

[Flowertime01 at wmconnect.com]

Rick,

You are good to go as is.

If you squint just right and pear into the R390 long enough, you will see 
there is not two little pegs on the Oldham coupler between the RF deck and 
the Crystal oscillator deck. Thus no place to hang a spring. Or your coupler 
may not be original. It could happen!

The Osc deck coupler should be a smaller dia than the VFO coupler. The 
coupler sets so close to the deck you cannot run a spring under it.

The crystal deck is in fact a switch and "continuous" It also has a 
reduction gear so some slop in the shaft is not a problem. As long as the 
"backlash, slop, play" does not keep the switch in the oscillator deck from switching 
on each megahertz change, the mechanism is OK and needs not repair.

A lot of VFO's are running with no spring on the coupler. A good receiver 
has very little play in the coupler. Most operators would never know if their 
receiver had the spring missing or not. Better to space the coupler faces 
apart a bit to keep from jamming a shaft into the VFO and getting more 
frequency off set from the deforming of the VFO mechanism. This again is not a lot 
but nice smooth operation is more fun to work with day in day out.

Any small spring you can work into the VFO Oldham coupler space will do the 
job.

Some children wear dental braces that use small rubber bands. These also 
work nice but only last a couple years before they give out.

Roger.
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