[NJARC] Philco 42-321

[Edward Otte]

Did I say variac, where is my brain today! Yes, there is a difference. I
think I have been thinking about getting a variac lately so I am confused. I
am much too young to get that confused. Thanks.

Edward

-----Original Message-----
From: njarc-bounces at mailman.qth.net [mailto:njarc-bounces at mailman.qth.net]
On Behalf Of Jim Whartenby
Sent: Sunday, April 08, 2007 1:42 PM
To: New Jersey Antique Radio Club
Subject: RE: [NJARC] Philco 42-321

Visit our web site - See http://www.njarc.org
_______________________________________________
Warning!  Isolation and Variac transformers are not the same thing! 
You will be shocked or killed outright if you don't know the
difference.
Jim
--- Edward Otte <edotte at optonline.net> wrote:

> Visit our web site - See http://www.njarc.org
> _______________________________________________
> 
> John,
> 
> By the way Happy Easter or Passover!
> 
> I did some measuring and if the plug goes in the wrong way it is a
> hot
> chassis. Yikes!
> 
> I am looking for a variac transformer because like you say, a good
> rule of
> thumb.
> 
> Edward
> 
> -----Original Message-----
> From: njarc-bounces at mailman.qth.net
> [mailto:njarc-bounces at mailman.qth.net]
> On Behalf Of john ruccolo
> Sent: Sunday, April 08, 2007 12:25 PM
> To: New Jersey Antique Radio Club
> Subject: RE: [NJARC] Philco 42-321
> 
> Visit our web site - See http://www.njarc.org
> _______________________________________________
> Hi again Ed,
> 
> I took a look at the schematic, and I do *not* think
> this is a hot-chassis receiver. To my knowledge,
> Philco did it the *right* way and used a floating B-
> bus (unlike Emerson, Fada, and others).
> 
> Still, the set could have been modified by someone
> not-so-knowledgeable -- a good rule of thumb with ALL
> AC-DC (power transformer-less) sets is to *always* use
> an isolation transformer when working on them.
> 
> Regards,
> 
> John
> 
> 
> --- Edward Otte <edotte at optonline.net> wrote:
> 
> > Visit our web site - See http://www.njarc.org
> > _______________________________________________
> > 
> > 
> > Jim,
> > 
> > I am not sure I fully understand. I just started
> > taken note of the schematic
> > and it dawned on me. Depending on how I hook the AC
> > plug into the socket the
> > chassis will either be ground/ neutral 0 volts or
> > 120 Volts hot! Yikes! So
> > the -B supply goes there too. 
> > 
> > But I agree with you how many Henry's could there be
> > in a wire twisted six
> > or seven times around a 1/2 inch capacitor. 
> > 
> > Edward
> > 
> > Edward
> > This is an AC/DC set and it predates polarized
> > plugs.  So it looks like
> > it is a series LC circuit used to connect the B-
> > power supply terminal
> > to the chassis.
> > 
> > It would be nice to know the inductance so we could
> > calculate the
> > resonant frequency.  Need to know how many turns of
> > wire and what is
> > the cross section of the capacitor? And then there
> > is the matter of Q.
> > 
> > I don't think Philco used this circuit for long.  I
> > don't remember
> > seeing this in a late 40s AC/DC set I reworked that
> > had AM and both the
> > old and new FM bands.  My gut feeling is that this
> > inductor is not at
> > all critical and can be deleted when you replace the
> > old wax coated
> > ones with modern capacitors.
> > Regards,
> > Jim
> > 
> > --- Edward Otte <edotte at optonline.net> wrote:
> > 
> > > Visit our web site - See http://www.njarc.org
> > > _______________________________________________
> > > 
> > > Hello all,
> > > 
> > > I have a general question about the Philco 42-321.
> > There is a
> > > "condenser &
> > > choke assembly" which consists of a 0.2 uF
> > capacitor with a number of
> > > wires
> > > wrapped around it. There is a Philco part number
> > but what if I wanted
> > > to
> > > replace it? The coil portion is just a wire and it
> > has a certain
> > > radius
> > > would I have to recreate this or is there an easy
> > solution? Thanks in
> > > advance.
> > > 
> > > Edward
> > > 
> > > _______________________________________________
> > > NJARC mailing list
> > > NJARC at mailman.qth.net
> > > http://mailman.qth.net/mailman/listinfo/njarc
> > > 
> > 
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> > 
> 
> 
> 
>  
>
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