[R-390] 390() vs 390(A), clattering away

[Drew Papanek]

Barry Hauser wrote:

>If the tuning motor goes out, you can always use your reversable, variable
>speed drill.  Just remove the knob, chuck up the drill on the shaft and go.
>Use a drill with an adjustable clutch, in case you're too slow on the
>trigger finger when you approach the stop.

>For those suffering from '390 wristitis, a "two-gun" approach can work on
>your R-390 or R-390A.  It will also give you some idea of what it's like to
>run an R-391 autotune -- on the cheap -- except for the part where it stops
>on one of the 8 pre-sets.  But then, again, most '391's don't get that part
>right unless tended-to in advance.  You will get a fair sample of the whine
>and clatter, though.

Many years ago I added a spinner to the Kc (not kilohertz!) knob on my '67 
EAC.  That was way back before any of the '390x clan had become sacred 
objects, so I am hereby granted absolution.  I used a Torrington needle 
bearing cam follower in a hole spotfaced and tapped near the knob's edge and 
it works quite well, perhaps a little too well.  When rapidly cranking to 
QSY I get at least the clatter portion of that "fair sample" alluded to by 
Barry, so much so that I am afraid to crank very fast.

The Veeder-Root counter seems to be the source of most of the clatter.

Drew