Home Forums Electronics Restoration Hallicrafters SX-71 Reply To: Hallicrafters SX-71

Ralph Spracklin
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Evening John

Your radio is of course was built to operate on a 12 Volt acid cell battery. The earlier version of this unit was also built to operatae on a six volt battery. I have attached a link to “radioremembered” ,which shows the schematics and an article, whichdescribes how those vibrator type powrer supplys work. However this schematic is for a six volt version. So it would need to be modified to suit the deands of your radio. If I were faced with the problem I would find an old 12 volt automobile radio and cannabalize ii for all the parts I would need, and would build a Power Supply for it. As for the six volts required for the Heater filaments, I would place a six volt tap on to of the 12 battery. Fot the HV side you would need make certain that the donor set had a Power Transformre rhat could provide 250 Vo;ts at about 51-60 ma.

Now all you will need is an airctaft to put the radio in. (haha)