[R-390] R390A not working at all Eyes Open

[Flowertime01 at wmconnect.com]

Kurt,

Eye ball four jumpers on the back terminal boards
RF gain TB102 pins 1 2.
Diode load TB103 pins 14 15
AGC TB102 pins 3 4

These things exist to allow the receiver to be operated in tandem with paired 
receivers.

Line audio TB103 pins 11 12. This one may be missing and the audio deck 
modified.
This is not a showstopper. If one of the other is missing just strap a wire 
across the terminals.

Short TB103 pin 9 to ground with a wire to a chassis screw.
Do a nice job you will want to leave this jumper on your receiver.
Switch the break-in switch off and on

You should hear the antenna relay click.
You should hear the audio noise mute.
The break in relay pulls the audio at V601 to ground.
You should just hear the hum from V604.
Set the break-in switch off.

If the break-in is not working, check you have a good jumper on the terminal 
board pin. Leave this problem for later. That poor relay likely has not been 
powered on for years.

Set the function switch to cal and mgc. You should hear the antenna relay 
click as you go from MGC to CAL. If not then you do need to work on that problem.
Passive off of the antenna relay is signal through the relay. A lighting 
strike may have fused the relay contacts. Again let this problem go until you at 
least have calibration tones on ever 100 KHz.

Set the dial to 7 +000 and look at the mechanical cam alignment.
Read the Y2K to see if your mechanical alignment is good.
Once you know you remember.

Next check the band switch operation.

This is under the Rf deck it switched the six racks of RF transformers. I 
call then octaves. One slug rack and three slugs in three cans per octave.

The bands switch at .5 - 1.0 band switch at
2.-3,  4-7, 8-15, 16, 32

As you change the MC knob you should see the band switch gears change.
Both going up the dial and down the dial.

Often a clamp will get loose, crack on a gear and drop the alignment.

There are several gears and clamps between the MC knob and the band switch.

NO FEAR you can change any clamps and reset any gear with out pulling the 
gear train apart.

The original TM says you can even set the band switch in the RF deck with out 
pulling the
RF Deck. DO NOT DO THIS. If you need to set your band switch then pull the RF 
deck and do it
By eyeball.

Several of the switch segments carry B+. You want the very best mesh and 
maximum switch contact
On each wafer section and contact on each band setting.
DO NOT try to adjust a wafer location of contact. You are just going to 
adjust for the best
You can get. It's an average of everything from end to end. You want to 
eyeball that not pick
A continuity check blind with a meter reading as detailed in the military 
TM's.

As you dial across the KC band from 00 500 to 00 900 you watch slug rack 1 on 
the left go from bottom to top.
As you dial the KC band from 01 000 to 01 999 you watch slug rack 2 from the 
left go from bottom to the top. 
As you dial the KC band from 02 000 to 02 999 you watch the slug rack 3 go 
from bottom to 1/2 way up.
As you dial the KC band from 03 000 to 03 999 you watch the slug rack 3 go 
from 1/2 way up to the top

The 04 to 07 999 takes four passes to make the travel from of slug rack 5 go 
from bottom to top.
Slug rack 5 needs 8 passes from 08 000 to 15 999 to make it travel its range.
Slug rack 6 needs 16 passes from 16 000 to 31 999 to make it travel its range.

Z216 travels bottom to top with each 000 to 999 KC ten turn of the KC knob 
pass.

Z213 bumps around with MC changes and moves a bit with the KC knob.
There is a pattern to its behavior.

All you are looking for is to see everything moving like it should.
You are just looking to see if a clamp come loose or a gear has slipped out 
of mesh.

This will get every thing out of sync in the RF deck.
It will not hurt any thing the receiver just will not work.

If your receiver passes all this eyeball then its time to put on the head 
phones and listen to it.

More to follow.

Roger AI4NI