[R-390] RF Deck Removal and Questions

[Barry Scott]

Alex,

The green gear doesn't exactly "lock" the gear train.  I keeps the sections
synchronized with each other when the RF deck is removed.  It is normal for
it to rotate like that.

Getting the backlash set is a bit fidgety.  I found it helpful to have
something that can keep the tension and the teeth of both halves matched up
during the process.  If I recall correctly, I loaded them and then pushed a
flat-blade screwdriver in the teeth to hold them until I could get them
meshed.  i think that's necessary for both sides.  Others may have better
advice for how to do that.

I don't know what might be used as replacement springs.

Thanks,
Barry - N4BUQ


On Sun, Mar 15, 2026 at 8:28 AM Alex Hopper via R-390 <r-390 at mailman.qth.net>
wrote:

> Hello All,
>
> Following my manual, I carefully removed the font panel on my R-390/URR
> (non-A) last night.  I am at a point where I would like to begin the
> process of removing the RF deck.
>
> How exactly is the green gear intended to 'operate'.  While the RF deck was
> still in place last night, I attempted to affix the green gear to it's post
> to the right of the KC change gear.  The green gear still moved in this
> position when the KC change was rotated.  Does the green gear work by
> locking the entire tuning mechanism only after the RF deck is removed?
>
> What other pitfalls should I look out for?  Reading the manual makes the
> process of replacing the RF deck sound MUCH more difficult.  Is meshing the
> gears back together as complex as it sounds?
>
> Finally, when the deck is out I would like to replace at least a few rather
> rusty and tired looking springs on the slug racks.   Is there a specific
> spring size/tension I should be looking for?
>
> Thanks,
> -Alex
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