[R-390] R390a Help

[Tisha Hayes]

If it was already rebuilt you should be in pretty good shape. The only
"different" things about the R-390A would be the speaker impedance of 600
ohms and depending upon how you feed the antenna.

The antenna has a 50 ohm unbalanced connection but it is on a "C connector"
on the back of the radio. There is also a balanced, 125 ohm connection with
the two pin plug near the C connector. For that you would need the right
kind of connector and possibly a impedance adapter to get to whatever your
antenna is matched for.

The radio takes 120 VAC (normally but it can be restrapped to 240) at about
2 amps. It is good for AM/CW and with a bit of tuning it can be fairly
effective on SSB. Most R-390's were intended for fixed frequency service on
RTTY but make pretty good receivers for amateur radio use.

There is a large number of tubes but really only a half-dozen different
types (more or less). If the radio has been rebuilt you should be OK with
the geartrain and alignment so unless you know what you are doing or have
something very specific in mind then keep out of the mechanicals. You would
do yourself good to get some NOS tubes that test good as quite a bit of the
troubleshooting and even performance peaking comes from having the best
tubes in the best spots.

Download the R-390A R2K guide. It goes into excruciating detail in how to
do just about everything to the receiver.

There are some work-arounds to match the speaker impedance from 600 ohms to
something like 8 ohms. Ask around, we have some good tips on that.

-- 
Ms. Tisha Hayes. AA4HA

*""In this denial of the right to participate in government, not merely the
degradation of woman and the perpetuation of a great injustice happens, but
the maiming and repudiation of one-half of the moral and intellectual power
of the government of the world." -- Fredrick Douglass"*