[R-390] Help with R-392

[Dan Merz]

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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