[R-390] Help with R-392

[Dan Merz]

Ronnie,  correct that capacitor to 54,000 mfd/30volt  not  5400 mfd.  It's a big one
!!,  about 3 inch diam by  6 inches long.  Dan.

Dan Merz wrote:

> Ronnie,  I bought a 392 years ago at a hamfest and my 392 guide  led me to build
> a power supply using a big transformer (I think it's 21 vac output) and a
> 5400mfd/30volt computer grade capacitor from the junk being sold at the same
> hamfest.  This has worked well for many years,  a very simple power supply
> initially.  I did add a relay/resistor to the circuit to reduce the initial
> surge to charge the capacitor when first turning on - otherwise I had to use a
> variac to bring it up or it would blow the appropriate fuse that I put in the
> power supply.  I believe it is as quiet as I need.  I can provide more details
> if you're interested in this approach but you can probably find one already
> assembled - I think I may have bought a regulated one since making mine but
> never used it.  I think mine puts out about 24 volts under load - my mentor at
> the time thought that was plenty - though I've read that the radio performs
> better with full 28 volts,  Dan
>
> Bruce Ussery wrote:
>
> > Ronnie,
> > For what it's worth, 3 amps sounds like about the right current draw. Both
> > of mine draw about 2.6 amps; one fluctuates between 2.6 and 3 as the
> > calibrator crystal oven cycles (I assume). So you must not have any bad
> > shorts or opens in the power string. We'll keep hoping for just a bad tube
> > or dirty contact. Oh- check the ant. relay just behind the front panel for
> > good contacts. With the contacts open, as when it's energized on standby, I
> > can barely hear the local 50KW bc station at 680kHz. Nice sheilding...
> > And I gave up on AC power supplies after trying three. They all radiated RF
> > noise, mostly below 8 Mhz, so I got a couple of big gel cells at a hamfest
> > and a "wheelchair battery charger" through the internet.
> >
> > Good luck,
> > Bruce
> >
> > ----- Original Message -----
> > From: "Ronnie Davis" <rdavis24@carolina.rr.com>
> > To: "R-390@Mailman. Qth. Net" <r-390@mailman.qth.net>
> > Sent: Wednesday, January 21, 2004 8:53 PM
> > Subject: [R-390] Help with R-392
> >
> > > 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.
> > > Thanks
> > > Ronnie
> > >
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