[ARC5] Hallicrafters S-38 is dangerous

[scottjohnson1]

The RCA 8516 was a great receiver, but alas it was transformerless!
Scott W7SVJ


Sent from my Verizon Wireless 4G LTE smartphone

-------- Original message --------
From: Dennis <dennis.monticelli at gmail.com> 
Date: 11/16/2015  5:05 PM  (GMT-07:00) 
To: Richard Knoppow <1oldlens1 at ix.netcom.com> 
Cc: arc5 at mailman.qth.net 
Subject: Re: [ARC5] Hallicrafters S-38 is dangerous 

The SBE 33 (an early sideband xcvr) ran a doubler directly off the mains and bolted the chassis directly to the metal case.  I wonder how many widows it made.  

They isolated the case with the SBE 34.

Dennis AE6C

Sent from my iPhone

> On Nov 16, 2015, at 3:17 PM, Richard Knoppow <1oldlens1 at ix.netcom.com> wrote:
> 
>    Badly designed only if a great many other AC/DC sets are also.  The S-38 and later receivers are made with the chassis insulated from the metal cabinet. Unless the insulation is gone due to age nothing on the outside of the receiver is connected to either side of the line.  There were certainly other AC/DC devices, such as cheap code practice oscillators, where the chassis _was_ connected to one side of the line was was hot with regard to a house ground such as a steam radiator if the plug was in the wrong way. Since neither plugs or sockets were polarized it was a matter of a 50/50 chance of getting bitten. Most home radios and phonographs with AC/DC supplies were in wooden cases which provided the insulation. However, the shafts of pots and tuning capacitors could be at chassis potential. If someone pulled an insulated knob off they could be in trouble.  Hallicrafters used Bakelite rods for the tuning controls and plastic knobs. I don't remember if the volume control o
 r bandswitch was hot. Given its simple circuit the performance is quite good.  A great many five tube wonder radios were on the market, mostly bc band only but some with one or more short wave bands.  The AC/DC supplies were mostly to cut costs but there were parts of the U.S. with DC current until fairly recently and many ships had only DC current.
>    The main danger from these sets are to the service people who work with the chassis out of the cabinet. An isolation transformer will prevent getting directly across the line but many are foolish and  work without them.
> 
> 
> 
>> On 11/16/2015 2:33 PM, J Mcvey via ARC5 wrote:
>> That radio is a badly designed AC/DC set with several ways to give you the "shock of your life".
>> Check out info on how to modify it for safety. I've done a few of these for people and I was amazed that this designed was allowed to be sold back in the day!As they age, the danger increases too.
>> Just another type of  Hallicrafters design debacle. No wonder they are not around anymore.
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> 
> -- 
> Richard Knoppow
> 1oldlens1 at ix.netcom.com
> WB6KBL
> 
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