[R-390] R-392 quest for power - Circuit idea...

Tue, 13 Aug 2002 19:19:31 -0700 (PDT)

Bruce,

There are two pins for power on the connector

Power Pins A & D +24VDC, Pin E is Ground

One is for the fillament/heater circuit, the other is the plate B+ supply. Easy to check one
lights the tubes!!!!

The B+ requirements are quite modest, so a simple 3 terminal regulator (such as a LM317 with
heatsink) from the +30v to the B+ will give you the quiet supply that you want without much
heat...

Regards,

Rodney
VK2KTZ

--- Bruce Ussery <[email protected]> wrote:
> Hi gang,
> I've had this R-392 (not an A, not a Chevy), for a couple of weeks and have 
> been enjoying it on the kitchen counter which is also green so it looks 
> great. It's an actual working radio, unlike the ones I usually bring home. 
> All bands fairly hot, fairly accurate.
> My only problem is finding a better way to power it. The homebrew supply 
> that came with it (very basic- xfmr, square bridge rectifier, 33,000 uf cap) 
> doesn't make any radio noise, but it has about 170 mV RMS ripple, which I 
> can hear on CW or SSB. It's also putting out right at 30V which worries me a 
> little. I've tried 2 regulated supplies; a Systron Donner bench type supply, 
> and a Power One open frame job. Their outputs are clean as a whistle, but 
> they both radiate a loud buzz into the receiver from about 8 Mhz on down. 
> (Too many solid state gizmos.)
> This temporary?? kitchen setup is truly less than ideal- a 15 ft. wire 
> across the top of the cabinets and no ground. A temporary ground hooked from 
> ant. ground to the AC outlet helped the buzz some, but it's gonna take more 
> I think. I verified totally quiet operation with two 12V batteries.
> I not totally against using batteries as a permanent solution- that's how I 
> power my "late model" ham rigs. It just gets messier having to deal with 2 
> batteries, lacking a 24V charger. Anyone have similar noise problems on the 
> lower bands?
> 
> (Craf-T-Bob, this thing sounds great with a Hallicrafters R-46 speaker 
> hooked up instead of the LS-166/U. The R-46 has a 500 ohm xfmr according to 
> the label- is that correct?  Close enough for me anyway...)
> 
> Bruce
> WA4ZLK
> 
> 
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