[R-390] 390-A VFO Rebuilders?

[Paul H. Anderson]

On Fri, 20 Apr 2007, W Gladhart III wrote:

> Hello Group, I've been awarded the care of a Collins R-390A. It was 
> received upside down with the VFO removed. The VFO shaft is stuck solid. 
> I picked up a beater replacement from Fair mainly for a set of 
> bearings(?) but I don't think I should attempt messing with it. Can 
> anyone recommend someone that can repair and align this VFO so I can 
> power the unit up and find what other surprises it holds in store?

Wes,

I suggest this strategy...

Make sure it is the VFO and not the front panel bushings or other parts of 
the RF deck.  Do this by removing the VFO from the radio.  The tuning 
shaft should turn freely with light fingertip pressure (do not force). 
You have an example from Fair to help you see what might be normal.

If it is stuck then, you are most likely doing triage on it - it likely is 
corroded inside, badly bent, or otherwise generally unrepairable, IMHO.

You can check for this by taking the cover off, which is fairly safe to do 
- in my opinion you're just looking to see if there is something grossly 
wrong that can be readily fixed.  So, pull stuff off, save the parts, and 
see if you can locate the problem - bent shaft, corroded bushings, broken 
parts.

Another perfectly reasonable approach, if the VFO itself is stuck, is to 
set it aside as a spare (or mid-winter repair project), buy another one 
that can be restored or used, and go with that one.

I lean towards replacement rather than repair because R-390A VFO's are 
relatively available at not too much money, and repair of this type of 
problem is best done 'because you want to' - not because it makes time or 
money sense to do so.

This is all my opinion, and clearly, there are many reasonable points of 
view on this.

Paul