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, February 16, 2012 8:27 PM
To: Antique Phonograph List
Subject: Re: [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
ohmmeter to determine if there is already leakage from either of the wires
leading from the motor to the case. An ohmmeter reading should indicate a
very high or infinite resistance from either wire to the case when things
are correct. If you measure any significantly lower resistance, the
internal wiring will need to be redone or repaired. If there is good
isolation from the motor wires to the case, I would recommend replacing the
line cord with a modern three-wire cord with a 3-terminal AC plug. Connect
the black and white wires to the motor circuit as was done in the original
2-wire cord. Then connect the green wire to a screw on the metal case.
This will privide a grounding connection from the case to your household
earthing system. If electrical leakage should develop in the future, it
will be routed thru the green wire to your household ground system (assuming
you plug the cord into a modern 3-wire outlet). In the worst case, it will
blow a fuse or circuit breaker rather than leaving the system a shock
hazard.
Greg Bogantz
----- Original Message -----
From: "Philip Carli" <philip_ca...@pittsford.monroe.edu>
To: "Antique Phonograph List" <phono-l@oldcrank.org>
Sent: Thursday, February 16, 2012 7:08 PM
Subject: [Phono-L] Does anyone know how to make a Jones Motrola _safe_?
>
> 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
>
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