[R-390] Zero adjust on R-390 receiver

[Thomas Frobase]

Just to draw this to a close, I talked to Howard on the phone today while we
walked through the calibration adjustment on a R-390 not "A" on a radio I
have here.

On the R-390 there is a spring loaded clutch which couples a set of gears
that is driven off of the main tuning shaft to the left of the main tuning
shaft with the radio upside down.  When the calibration knob is screwed in
it raises the clutch and allows the main tuning knob to turn about a quarter
of a turn, the second gear toward the rear of the radio is disengages thus
not allowing the counter to move.  It looks like the clutch on his radios is
stuck with old grease.  The clearance on the clutch is very small and hard
to see.

And that is all I know about that!

73, tom, N3LLL

-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
On Behalf Of howard m. mills
Sent: Saturday, March 16, 2013 11:32 AM
To: r-390 at mailman.qth.net
Subject: [R-390] Zero adjust on R-390 receiver

Can anyone explain how the Zero Adjust works on an R-390 receiver.  I have
two of them and the Zero Adjust doesn't work on either one.  The manual is
of no help.

 

Howard

W3HM

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