[R-390] Help with R-392

[Paul H. Anderson]

On Wed, 21 Jan 2004, Ronnie Davis wrote:

> Hello again
> Well I ended up with a good condition R-392. Has a couple problems that I
> will have to work out before im happy. One is the coupler disk that changes
> the filters is missing. Does anyone know where I can get the little coupler?
> Looks about like the VFO coupler on the R-390A but a lot smaller. Right now
> its in the 8 kc position but I would like to be able to change it. Also, rig
> is powering up fine but have not heard any stations yet? Just a static,
> going to clean the contacts on all the tubes and see if that helps. It is
> alot tighter in the R-392 than it is in the old R-390A. So if I do any cap
> replacements in this thing it will be a real job hi. Anyone know of a good
> cheap PS to run the R-392 on? My PS is struggling to provide the 28 volts at
> 3 amps. Anyone that can help with the R-392 please do, and I will sure
> appreciate it. Oh yea, the second R-390A is getting a Recap kit from Walter
> now. So I have two radios on the bench at the same time.

I'd suggest replacing caps only as needed when shorted.  It is too tight
to do a good job in there, and more importantly, at 28V B+, the caps
aren't stressed very hard (most are 200V, if I recall).  The inside of the
cabinet certainly gets a little toasty, but I haven't really noticed heat
or age related problems like the audio deck of the R-390 or R-391.

I get lambda power supplies from ebay - if you watch for awhile, you
should be able to get one for a winning bid of $15-$25 no problem.

There is a slight chance the coupler is in rattling around in the case
somewhere - might be worth a look.  I dunno where to get a new oldham
coupler that size.

See if you can hear the crystal calibrator?  Static means the audio stuff
is probably working and that you don't have any serious B+ shorts, so the
likely culprit is closer to the antenna.

I've lost more PTO tubes than about anything else, but at any rate,
testing all the tubes is worthwile.  I brought a scrappy 392 back to life
recently just by testing and replacing the tubes (I think I had to replace
3 or 4).  If no tube tester, get spare tubes that are believed to be good,
and start swapping them around.

Paul