[ARC5] A.C. Modified BC-348

[Michael Hanz]

Schematic attached.  There were apparently two different rectifier tubes 
used in the EP-298 Halli supply - initially a 5Y3GT, then a 6X5GT-G - 
which has a separate cathode independent of the filaments.  It is not 
hard to anticipate the eventual substitution of a 25Z5 to eliminate the 
filament winding in the transformer...

No "safety" issues with that design.

On 8/28/2021 10:41 AM, J Mcvey via ARC5 wrote:
> A 25Z5 implies a "series string/ hot chassis circuit.
> The BC348 design does not lend itself very well  to a transformerless 
> power supply.
> Then again, Hallicrafters was famous for grounding one side of the AC 
> supply to the chassis!.
> This kind of mod is unsafe, IMO.
> However, safety did not seem to be a big concern "back in the day"...
>
> On Saturday, August 28, 2021, 12:29:46 AM EDT, Hubert Miller 
> <kargo_cult at msn.com> wrote:
>
>
> Here's a 348 i found in my stash. The rectifier tube is a 25Z5, which 
> means a drop -in supply with minimum mods. Unfortunately tho, the 
> cabinet top has been aerated. The PS has no markings really except for 
> this on the tube area shield:
> "TESTED GOOD 11/10/ 45 ROB". Too early to have hit the surplus stores, 
> so this must be a gov't mod.
> -Hue Miller
>
>
>
>
> Sent from my Verizon, Samsung Galaxy smartphone
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-- 
Michael Hanz - KC4TOS

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