[R-390] A Little Help Needed

[Flowertime01 at wmconnect.com]

Carole White-Connor

I hope you have access to a network connection with better than dial up speed.

wander over to the following web site.

http://www.r-390a.net/


There is a manual there called the Y2K manual and original military TM's and 
lots of other stuff to read.

As you are on the reflector there is also lots of archived topics to read.

Download your self an electronic copy of the Y2K manual for starts.
It is better organized and reads so much nicer than the original military TM's

You will need any old Rf signal generator that will do 500Khz to 30Mhz and 
has am modulation.

You will also need a DC volt meter and an AC volt meter. Any flavor that will 
read about 30 volts or less will work.

You would like an AC volt meter with a DB scale and enough knowledge to be 
able to use the meter on the audio output of the receiver and determine a signal 
to noise ratio when the RF generator is putting out straight RF and when the 
generator is putting out modulated RF.  You can use two 1200 ohm resistors in 
parallel to make a 600 ohm load to go with the AC volt meter on the Local Line 
output on the rear panel of the receiver. If the AC volt meter does not have 
a DB scale you can convert the AC voltage across 600 ohms to DB and determine 
if you have the signal to noise ratio you need (10:1 is OK specified, 20:1 is 
very do able with the receivers today, 26, 27, 28:1 is often seen, 30:1 is a 
holy grail and still seen in receivers today, You may only get that on some 
bands)

More equipment is always good, but this is all you really need to align and 
test your receiver.

The first level is a cal tone at every 100Khz from 500Khz to 31,000+.

Once you have a receiver that has all the knobs and functions working you can 
move on.

Worry not that MGC and AGC has little difference at this point.

Do pull the IF deck and determine if the old big fat plastic caps are all 
gone. There should be nice new caps in the IF deck.

Someday you also want to pull the RF deck and see that some old big plastic 
caps have been replaced in that deck as well.

Check the two plug in electrolytic caps on the audio deck. These likely have 
been replaced. By caps under the deck. new caps stuffed into the old original 
cans. Some nice replacement work, some not so nice work you may want to 
upgrade someday.

There is also an electrolytic cap in the audio deck on the circuit board that 
should have been replaced at least once or more in the life of the receiver. 
Inspect the board for a mess of corrosion and a nice new cap C609 a 8UF cap. 
Any thing larger than 8 UF and 30 volts will work.

Many audio caps may have been replaced with larger value caps. This improves 
the audio band width (fidelity).

C553 a .01Uf cap in the IF deck keeps B+ from V501 off the mechanical filters.
Check that this cap in the RF deck has been replaced with a modern cap.

If this cap fails, the B+ kills the mechanical filters.

You will find all this stuff on W Li pearls of wisdom on the web page.
As a new owner, or an old receiver, read it all once and make the inspections 
needed on your receiver.

Down load the manual of your choice and go through the alignment procedures 
and test. As you get to a point and wonder what to do, post a question here on 
the reflector. Several Fellows will send you some good advice on what to do 
next.

We have no idea of your skill level, Start where you can, do what you can do 
and start asking questions. We will help.

Good luck and welcome to the group.

Roger L. Ruszkowski AI4NI   </HTML>