[R-390] R-390A DIY alignment completed at last!

[frank hughes]

Hi,
Using the training videos from Chuck, I was able to complete the alignment
of my R-390A
this weekend!
This is the first time I have done any work on this receiver.
I bought it from Rick Mish in 2008, and after 4 years of use I was told to
expect the receiver to require this maintenance.

It has taken me a couple of years to acquire the test equipment.
After initially watching Chuck's videos four years ago, I started looking
for the same test equipment he was using.
The idea was since I have only a vague idea of the principles and
procedures involved, using the same test equipment would let me skip the
step of learning test equipment configuration, and just let me concentrate
on the radio part.

I have frequently bought broken HP equipment and repaired it.
Many times a fresh set of Electrolytics restores functions.
Sometimes a shorted Tantalum needed to be located and replaced also.
When I could not find a repairable unit, I just bought a refurbished one.
(The 8640B was rebuilt)

The other reason that I have been trying to learn how to align the R-390A,
and have acquired test equipment, is that I need to figure out how to align
my R-390 and R-392.

No training videos exist for these receivers, so hopefully they are not
very different to align from the R-390A, and the training methods will
transfer over.

The only thing I had trouble with (and have yet to understand how to do) is
the "10db signal to noise"
performance adjustments.
I understand how to set up the HP 3400A and the receiver adjustments, but
don't understand how to set up the AM and modulation on the HP 8640B the
way Chuck is doing it in the video. I have the HP 8640B manual, but it was
written for an electrical engineer, not for me!

Also, after all the alignment was completed, I used the "alignment adapter"
from Kurt DH3PJ to set the RF deck "balance" capacitors to maximum common
mode rejection ratio (CMRR), worked great!

73
Frank
KJ4OLL