I have a Jones Motrola I'm trying to rewire, but I read that they can be
dangerous in their original ungrounded state? Any ideas on how I can deal with
this? Any help would be appreciated. Thanks, Philip Carli
This email message and any attachments may
I always wear sneakers and rubber work gloves!
George P.
-Original Message-
From: Philip Carli philip_ca...@pittsford.monroe.edu
To: Antique Phonograph List phono-l@oldcrank.org
Sent: Thu, Feb 16, 2012 7:23 pm
Subject: [Phono-L] Does anyone know how to make a Jones Motrola _safe_?
I believe the Motrola has a metal case. The danger can occur if there
is electrical leakage from the internal wiring to the case and its attached
metal parts which can occur due to carbonized insulation that can begin to
develop a lower resistance. I would recommend first testing with an
Many thanks! Another suggestion I've had is the use of an isolation
transformer at the plug - any thoughts on that? PC
From: phono-l-boun...@oldcrank.org [phono-l-boun...@oldcrank.org] on behalf of
Greg Bogantz [gbogan...@charter.net]
Sent: Thursday,
Would soldering the green wire to the case do as well as a screw? I believe
the case is pot metal and tapping it for a screw might shatter the whole thing.
Philip Carli
From: phono-l-boun...@oldcrank.org [phono-l-boun...@oldcrank.org] on behalf of
Greg
The NEC (National Electric Code) doesn't normally allow soldering for power
connections. My guess is that they are concerned that a high current fault
(short) could melt the solder.
Jim Nichol
On Feb 16, 2012, at 9:58 PM, Philip Carli wrote:
Would soldering the green wire to the case do as
An isolation transformer would not prevent getting a shock from the case
of the Motrola if it develops internal leakage. Grounding the case of the
unit as described previously is the best plan.
Greg Bogantz
- Original Message -
From: Philip Carli
Potmetal can't be soldered, typically. You can use any screw anywhere
inside the unit that is electrically connected to the case for the purpose
of attaching the green grounding wire. Make sure that your connection point
is NOT connected to the motor wiring - test with an ohmmeter. A
Hi Philip ~
1) Soldering to pot metal might not be possible, depending on the composition.
2) Tapping a screw thread in a correctly sized hole for that tap, with cutting
oil and reasonable care, poses very little risk unless the casting is full of
cracks (In which case it wouldn't be safe to
The proper way to test the winding insulation is with a HiPot tester or high
voltage ohmmeter. A conventional handheld ohmmeter does not provide the
necessary voltage to validate the insulation resistance integrity.
Using an isolation transformer alone is a bad idea. If the windings leak you
will
Phono listers:
What are the thread sizes for the thumb screw on: Victor:
exhibition, n. 2, and 4a reproducers?
again thanks
Bob
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It your not livin on the edge your takin up to much room. Heck you might
get across the 110, it will light you up, that's all. If it is typical of
early devices like radios with a metal case I would guess your problem
would be that the case is not tied to the neutral but the hot. If you get
If the case is neutral with respect to the two pronged plug and you ground
the case be careful. if you don't have you plug polarized you may blow a
fuse and most violent way. Early tools and etc worked w/o benefit of a
green ground wire, instead the neutral served that purpose. For a
phonograph
The proper way to test the winding insulation is with a HiPot tester or high
voltage ohmmeter. A conventional handheld ohmmeter does not provide the
necessary voltage to validate the insulation resistance integrity.
Using an isolation transformer alone is a bad idea. If the windings leak you
will
I want to thank everyone for their help; my brother-in-law (who is something of
an electromechanical genius) and I will be taking a shot with considerably more
chance of success thanks to your suggestions.
And in the end, if we can't get it work with consistent safety and reliability,
how hard
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