[R-390] Non_A

[Paul H. Anderson]

Paul - since it sounds like you have only one R-390, it might be a slight
bit harder to get it going (not having other modules to swap to see what
works and what doesn't).

However, it will help to figure out what you want to accomplish.

You mention it being apart ready to clean - that's one thing, the other
thing is that it didn't work before you took it apart - no signals on any
band.

If you're not so confident about your ability to repair, it might make
sense to get it back together and try and see what is working and what
doesn't.  There are a bunch of things to check to get the basic things
going, for example the B+ voltage measurement point should be around 180V
when operating (and if it is 180V, then I think three tubes are working -
the ballast, the VFO tube and the VR tube(s)).  If not, then you find out
why B+ is wrong, so you check resistance to ground, see if there is a
short there, and also check the VR and ballast tubes.

The ballast really isn't a big deal - I like having them, but they aren't
of any great practical use to the hobby users, because we don't usually
use them on battleships.

Anyway, after making sure you've got B+, then you listen to what you can -
see if you can hear any audio at all (even clicking when turning the
limiter switch on), or if you get a hiss with the RF cranked to the max.
That helps tell you if the audio deck is working.

On the R-390/R-391, I found the voltage regulator circuit for B+ to be the
biggest pain in the backside.  The 6082 tubes just fry the unholy crap out
of the bottom of the audio deck.  Check the 47 ohm resistors under there
and under the power supply to make sure they're close (if well used,
they're probably toast).

I've got one audio deck that just frustrates me to no end - I've replaced
all components in the VR circuits, and still don't get 180 volts.  Other
decks I've repaired responded well to the new 47 ohm resistors.

Dive into it - ask questions - we'll help!!!

Paul

On Wed, 7 Jul 2004, Paul Staupe wrote:

> Folks,
>
> I have to agree with Les.... I'm glad the pot's been stirred.
>
> As a member of this list from the beginning, it's fun to look back at
> the good 'ol days... Dr. Jerry, Noel, etc...  I can't imagine such a
> wealth of knowledge being given to the unwashed masses for free!
>
> However, I've got a problem.  I have a non-A that has been sitting in
> pieces in my living room for several months (I'm embarrassed to tell you
> how many), supposedly ready to be cleaned up, but in reality due to fear
> that I would screw something up.  The green gear was inserted at the
> appropriate time, so that's not a problem, but it occurred to me a few
> days ago that the symptoms... nothing on any band... might be attributed
> to a failure of the ballast tube...
>
> Should I go through the standard cleaning procedure and risk damage to
> the modules,  (and by the way, should I pull the coils out of the RF
> module when I clean it?) or just put it back together with a  new
> ballast tube and see if it works?
>
> Wimpily yours,
>
> Paul
> Kansas City
>