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

[rbethman]

Take a look at the clutch plate.

*IF* the plate has come loose and rotates, then it won't work right.

It is a press fit.

If it has come un-done, I don't know what you can do to get it back to 
working.

Bob - N0DGN

On 3/16/2013 3:44 PM, Bob Young wrote:
> The front panel is fine and I'm pretty sure the clutch plate is original and I would think it was dried lube except that Chuck Rippel restored it 7 or 8 years ago and I know it was very well lubed when I got it back and it still tunes like butter except for between 300 and 400 Kc going down. I'll have to bite the bullet and pull it out of the case to see what's up, I'm pretty sure it was fine when it came back.
>
> Bob
> KB1OKL
>
>> Date: Sat, 16 Mar 2013 14:21:43 -0500
>> From: n4buq at knology.net
>> To: r-390 at mailman.qth.net
>> Subject: Re: [R-390] Zero adjust on R-390 receiver
>>
>> That's the way my  Motorola clutch worked (or, more correctly, didn't work).
>>
>> A couple of things to check.  Are all the screws in the front panel?  If
>> not, it could be allowing the panel to bow more than it should.  Second,
>> is the clutch plate (the disc that's on the end of the front panel screw
>> thingee) solid and made like it should be?  My Motorola had a rather
>> home-made looking device which I replaced (it still didn't work like it
>> should, though).
>>
>> Could be that there is dried lube between the clutch plates.  I don't
>> think they're supposed to be lubricated with any kind of "wet" lube"
>> like oil, etc. (maybe, if anything, a dry lube like talc(?)).  If so,
>> the plates could just be sticking together with grease/oil.
>>
>> I seem to recall Roger having some thoughts on this way back when I
>> worked on mine.  Maybe he'll chime in.
>>
>> Barry - N4BUQ
>>