[R-390] Fwd: Antenna trimmer drawings

[Jordan Arndt]

To Jacques, Barry, Nick and the group...

To recap to this point:

After working on the underside of the RF Deck, I tried to re-install the 
deck into the radio, but it was a very tight fit, and more difficult than 
any other I have ever worked on. Some surface(s) was/were binding.

In the end, I had to supply some downward force for it to fit and as a 
result, the deck slipped past the binding area(s) and hit the chassis rather 
hard on re-installation.

Once the rig was all back together, I noticed some noise in the audio as the 
Ant Trim control was rotated with some bands worse than others. There was no 
such problem prior to that time, but there were some caps I knew needed 
replacing so I pulled the deck and did the work...

After reading Larry Haney's document on repairing a similar problem, I 
pulled the Ant Trim assembly and tried to remove the roll pin to 
dis-assemble and verify the assembly internally. Larry found an offset 
within the variable cap which created some level of contact between the 
rotors and stators. which he corrected.

His article can be found at :
https://www.r-390a.net/R390A%20Antenna%20Trimmer%20Cap%20Repair.pdf

I did use the correct roll-pin punch with the "half-moon" nub and recess 
collar, with no success whatsoever, and the head of the punch eventually 
broke off.

What I ended up doing was loosening the retaining nut as much as possible 
which alllowed me to inspect the centering insulator under the nut for 
cracks or voids and then I flushed the entire assembly with degreaser and 
then with a residue free contact cleaner. I was very surprised with the 
amount of grit and gunk that was deposited on a paper-towel after that 
cleaning.

I've re-installed the assembly onto the deck and resoldered the connections 
and I will temporarily re-install the RF deck to see if the flushing has 
solved the problem.

I recall reading about similar problems caused by gunk building up in the 
assembly many years ago, but if the flushing out of the assembly doesn't 
solve the problems, I'll be back to having to remove the roll pin to get 
inside the assembly for a thorough examination...

It's not very difficult to remove the assembly, and much much easier than 
pulling one of the IF transformers for example...

I hope this answers some of the questions some of you have had, and I'm 
sorry to be so wordy...!

73...Jordan VE6ZT