[R-390] WB3FAUs R390A update

[Flowertime01 at wmconnect.com]

Russ,

If you just have to loosen the clamp on the band switch and make an 
adjustment,
I really encourage you to pull the RF deck and set that adjustment by eye 
ball.

I know all the TM's and manuals say you can set the thing with a meter and 
such.

But remember you are dealing with an old receiver and you know not how it has 
been treated in the past.

My rational follows.

The band switch is six each six position wafer switches spaced over about 4 
inches of switch shaft.

Not all the wafers are in optimum alignment. Never were never will be.
In 50 plus years some of the parts have warped a bit.
In 50 years some of the parts are worn a bit (wafer hole to shaft).
In 50 years some of the contacts have oxidized a bit.
In 50 years some of the contacts have arced a time or to.

Pull the deck and set the shaft alignment by eye ball for optimum contact.

Check all the switch positions and all the switch sections.
Check the operation switching both up and down the band.
Then by best feel align switch shaft to gear for most best switch wiper to 
switch contact area in all 36 points. Best adjustment is still a judgment call. 
But better to do this by eye than with a blind meter reading.

Once you do this once you will not have to do it again until the clamp on the 
band switch slips (maybe never again).

But if you have to do it do it the very best you can.

If you have a switch wafer that's not exactly pristine and you do not set it 
the best you can then you are going to start burning some more metal off the 
edge of a contact and just make more maintenance nightmares.

Unless you have a contact that is just burnt bad. Just do the best you can to 
get things adjusted. Do not try to reset a wafer section or worry about 
excess play in the shaft to wafer sections. As long as you can get the assembly to 
adjust you will be OK.

The objective is to just do the adjustment by eye the best you can rather 
than do it blind by meter.

Roger AI4NI
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