[Elecraft] 12 v power source for Elecraft Transceivers

[jerry]

On 2022-12-06 10:54, Edward Mccann wrote:

> 
> Clearly case of stimulation of overactive ham hormone resisting
> disposal of anything looking potentially useful.
> 
*** That happened to me!   I was working at a railroad electronics shop. 
It
was around 1985.

One day, the boss decided to clean house.  Among the many goodies I 
rescued
from the dumpster were

* 4 Large 48VCT power transformers
* A berry box of TO-3 PNP Darlington transistors
* A giant heat sink, drilled for TO-3 transistors

...So I built a power supply.  I bolted 5 of those Darlingtons to the 
monster
heatsink, put them in parallel with emitter resistors, in the negative 
leg of
the output of my bridge rectifier, which was bolted to a thick aluminum 
bottom
plate.  This allowed me to ground the collectors of the transistors and 
dispense
with insulating washers.  Using the input taps of the power transformer, 
I was able
to adjust it for just the right head room.

   That supply did 20A with no fuss whatsoever.  I think it was actually 
capable
of 40A.

   This year, I dug it out of the junk, powered it up - and it still 
works!  Not
only that, it was 12.000V.

   Another use I found for this stuff - the flea market had yielded up a 
mint condition
Galaxy V transceiver.  But it had no power supply.  I took apart one of 
those big 48V
power transformers and rewound it, to make a supply for the V.

                      - Jerry, KF6VB






> Thanks all!
> 
> Ed McCann
> AG6CX
> 
>> On Dec 6, 2022, at 10:47 AM, Edward Mccann <edwmccann at gmail.com> 
>> wrote:
>> 
>> Tnx Jim.
>> Label claims  to be 12DC out, but clearly needs to be measured as 
>> investigation proceeds!
>> Minimal specs, but autopsy underway.
>> 
>> Ed McCann
>> AG6CX
>> 
>> 
>> 
>>>> On Dec 6, 2022, at 10:29 AM, Jim Brown <jim at audiosystemsgroup.com> 
>>>> wrote:
>>>> 
>>>> On 12/6/2022 10:16 AM, Edward Mccann wrote:
>>>> Slightly off topic, I will admit, but in reworking garden walkway 
>>>> low-voltage (12 v DC) I made surplus a 200 VA transformer.
>>> 
>>> Is what you have a transformer (two windings on ferrous core, 
>>> providing low voltage AC) or a power supply (transformer plus 
>>> circuitry to provide DC output?
>>> 
>>> 73, Jim K9YC
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