[R-390] Gear Train Alignment At +7.000

[Flowertime01 at wmconnect.com]

Barry,

I think the item we are missing here is some black lines scribed on the cams 
and RF subassembly. Hopefully your receiver still has them. These lines were 
just inked on during manufacturing. Aggressive cleaning of the chassis is known 
to remove the lines.

At +7.000 a line on each cam will line up with a line on the RF deck face. At 
+7.000 all the cams are mostly pointed up, and it makes it easy to check the 
alignment.

Two ways into the alignment after replacing the clamp (Quick, Full Process)
Depending on the clamp that is being replaced the outcome is more or less 
precise.
If its the 16-32 band, the outcome of a quickie is more positive than if you 
are doing the 5.-1 band. Always more precision in adjustment is better 
receiving.

1. Check the zero adjust. This is an eyeball to center it in the midpoint of 
the adjustment range. Do set it to center.

2. Check the dial counter over run on each end. It should be at least 25 or 
more on both ends. A. change the zero adjust a little to get both over run 
counts equal. B. drop the dial cover and reset the over run (this should be 
followed by a full RF deck alignment). If your receiver has had a full up good 
alignment, the dial over run should be good.

3. Roll the count up to 7.000+ and look at the cam alignment marks. All 6 RF 
band cams should have their marks aligned (except the one with the broke 
clamp).

4. If the-5-1 bank mark is off just a little, you can do a zero adjust of  
2 or 3 maybe 5. If its off more than that, then a mechanical cam adjustment 
and signal alignment are in order. (The receiver will work as is, some of us 
are just fanatics)

5. If some of the other band cams are off, consider a full mechanical 
alignment and full RF alignment. Mechanical being an eye ball thing. RF being the 
signal generator and slug alignment.

6. When installing the new clamp consider where the clamp bolt goes and where 
the spline wrench is going to be placed to adjust the bolt. Once you get the 
new clamp on the shaft, rotate the clamp so you can get the wrench on it. 
Rotate the cam to the alignment lines. And tighten the clamp.

7. If you had a full up running receiver, you can just put the new clamp in 
on the visual alignment and be done with it. If the receiver is carefully 
aligned, then loose and broken clamps can just be reset, replaced and your good to 
go. The mechanical setting of the clamp should be within the zero adjust 
range. You are trading VFO frequency against the band pass skirt of the RF band 
section in use (the one with the to be replaced clamp). The old prior proper 
planning prevents poor performance applies here.

Roger L. Ruszkowski KC6TRU

What is a relationship between the Geneva drive and the 7.000+ position on
the cams?  I don't know how to determine this.  I assume that when
approaching the 7.000+ position, the Geneva drive's gearteeth are in a
certain orientation.  In other words, it has most likely just clicked the
bandswitch gear just before or just after the 7.000+ position.  The gear
teeth on the Geneva drive are intermittent and do not click the bandswitch
between every band and there is some correlation between it and the 7.000+
position, I just don't know what it is.

Can someone help me out here?  Hopefully I'm being clear with the question.

Thanks,

Barry(III) - N4BUQ