[ARC5] Hallicrafters S-38 is dangerous

Tue Nov 17 00:00:52 EST 2015

The older the paper cap, the bigger the risk.  We deal with a full range of
old sets at CHRS, from the 20's up through the 70's.  AC safety caps are
cheap as is the three wire cord discarded from an obsolete computer.

Don't just think of yourself.  Think of the next person that will own this
radio.

Dennis AE6C

On Mon, Nov 16, 2015 at 8:51 PM, J Mcvey via ARC5 <arc5 at mailman.qth.net>
wrote:

> What I have stated is true for all of the s-38 series.  There is a cap
> that connects between the hot internal B- and the exterior cabinet . You
> have a 50/50 chance the ac is pluged in the "right" way. there was never
> "insulation" with respect to the metal exterior unless you consider that
> old cap to be insulation.
> Some people used isolation transformers, but it's better to mod the thing
> with some minor internal wiring changes to the power switch config plus
> proper AC safety caps and at least a polarized plug if not a three prong.
> The Green third prong ground goes to the metal case.  Now you are
> definitely safe.
>
> If you want to play Russian Roulette, that's OK too. You have been duly
> informed of the potential danger so it's up to you.
>
>
>
>
>      On Monday, November 16, 2015 10:50 PM, "Fuqua, Bill L" <
> wlfuqu00 at uky.edu> wrote:
>
>
>    Naturally, you would probably remove the AVC on the IF when you used
> the feedback.
>
> ________________________________________
> From: ARC5 [arc5-bounces at mailman.qth.net] on behalf of Fuqua, Bill L [
> wlfuqu00 at uky.edu]
> Sent: Monday, November 16, 2015 10:21 PM
> To: Richard Knoppow; arc5 at mailman.qth.net
> Subject: Re: [ARC5] Hallicrafters S-38 is dangerous
>
>   Every household had at east one AC/DC radio and sometimes a AC/DC TV
> although in the 506 and early 60s most TV's had transformers but later went
> to
> voltage doublers wit solid state rectifiers.
>   Saying that. Imagine how a S-38 would have performed if:
> 1. Used replaced V5, with a 12SA7 and made it a BFO and PRODUCT detector!!!
> 2. You had put some adjustable feedback in the IF to make a sort of
> Q-multiplier for CW.
>  Now that would have been cool.
> I don't see why product detectors did not catch on earlier.
>
>   73
> Bill wa4lav
>
>  ________________________________________
> From: ARC5 [arc5-bounces at mailman.qth.net] on behalf of Richard Knoppow [
> 1oldlens1 at ix.netcom.com]
> Sent: Monday, November 16, 2015 6:17 PM
> To: arc5 at mailman.qth.net
> Subject: Re: [ARC5] Hallicrafters S-38 is dangerous
>
>     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 or 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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