EAC R-390A #2
This is the my newest R-390A, and boy does it look new! I picked this
up on the way to Dayton 2001, making a little side trip along the way. I
didn't know what I was getting. I had been told the label read
"Collins", but the owner called me back later and said it wasn't
Collins, and did I still want it. For the price I paid, it would have been
OK if it were a non-working parts unit. After rattling off a few
manufacturer names, I called out "Electronic Assistance Corporation,"
and held my breath. "Yea, that's it." The rest is history.
My heart really sings when I look at (and caress and fondle) this
radio. I've never seen one this nice before. The green painted screw
heads are not even missing any paint, so you can't even tell if the modules have
ever been removed. Take a look at the "before" pictures below.
It's pretty clean on top. A little dust, but very nice. Black
tube shields. It's got the BFO knob that was often used for RTTY.
It had a bad line filter (still installed in the picture below), and the last
owner had bypassed it with a two-line power cord wired in through the top.
Bah!! Out it comes along with the bad line filter, and a good line filter
and three-wire line cord are the first requirements.
Underneath, it practically sparkes! Take a look at the gears. I
can't even detect any signs of lubrication on the gears. This one is
clean.
I put it on the bench to check the sensitivity, and if course it needed a
little work. First pass sensitivity ranged from 0.65 to 3 uV. After
adjusting the IF gain down a bit, it ranged from 0.35 to 1.5 uV. As I
began to do the first alignment pass on this one, I found that the ANT TRIM
capacitor was not at minimum with the knob set at zero, so I corrected
this. The sensitivities REALLY began to drop afterwards. After the
first alignment, I'm seeing sensitivities ranging from 0.085 to 0.12 on most
bands, climbing higher towards 0.20 uV as the frequency climbs towards 32 MC.
EAC R-390A #1
Here's the EAC that I picked up at Dayton 2000. It was in the main
operating position until recently. Now the Collins is back in the main
position and this one waits in line for some further alignment and tweaking
It came with an extra AF deck that had the Kleronomos Real Audio mod half
finished, which I will finish. It has a Cosmos PTO that I have been able
to adjust within about 200 Hz or less all the way from top to bottom.
There were several "performance" mods that really did nothing but add
some distortion and lessen the bandwidth, so they were removed. I've added
back a few of my favorite mods, such as the SSB/AGC mod and the inrush limiter
and an easy ballast tube substitution mod just in case the ballast tube ever
fails.
Here is the IF deck after replacing all the paper caps and a few out-of-spec
resistors.
Here is the front panel after repainting.
Here is the inside of the Cosmos PTO. I had to remove half a turn from
the end-point adjustment coil.
I had a few noisy tubes in this one, but still have a little more
"tweaking" to do. The sensitivity is mostly less than 0.3 uV
(-137 dBm) at the present time.
Last edited: 06/17/2002
