Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_?
Not true Greg. You would have to touch 2 different places with potential to get a shock and the case can't have that. Unless the isolation transformer is bad it makers it safe. That is how you can use those AC/DC sets with the case hot safely. The isolation transformer isolates it from ground completely. On 2/16/2012 10:10 PM, Greg Bogantz wrote: 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 philip_ca...@pittsford.monroe.edu To: Antique Phonograph List phono-l@oldcrank.org Sent: Thursday, February 16, 2012 8:45 PM Subject: Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_? 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 This email message and any attachments may contain confidential information. If you are not the intended recipient, you are prohibited from using the information in any way, including but not limited to disclosure of, copying, forwarding or acting in reliance on the contents. If you have received this email by error, please immediately notify me by return email and delete it from your email system. Thank you. ___ Phono-L mailing list http://phono-l.org ___ Phono-L mailing list http://phono-l.org This email message and any attachments may contain confidential information. If you are not the intended recipient, you are prohibited from using the information in any way, including but not limited to disclosure of, copying, forwarding or acting in reliance on the contents. If you have received this email by error, please immediately notify me by return email and delete it from your email system. Thank you. ___ Phono-L mailing list http://phono-l.org ___ Phono-L mailing list http://phono-l.org -- -Barry ___ Phono-L mailing list http://phono-l.org
Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_?
The isolation transformer does NOT make it safe. We use isolation transformers when working on TVs/Radios with a hot ground so that when we connect the ground lead of our instrumentation, we don't see fireworks. The isolation transformer allows the isolated circuit to float to whatever potential the leakage or forced paths take it. It is true that the only way to experience a shock is to come in contact with two significantly difference potentials. I think this discussion of shock hazards already had the premise that a potential near ground was available for accidental contact along with a faulty motrola. Bruce -Original Message- From: phono-l-boun...@oldcrank.org [mailto:phono-l-boun...@oldcrank.org] On Behalf Of Barry Kasindorf Sent: Friday, February 17, 2012 6:10 AM To: Antique Phonograph List Subject: Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_? Not true Greg. You would have to touch 2 different places with potential to get a shock and the case can't have that. Unless the isolation transformer is bad it makers it safe. That is how you can use those AC/DC sets with the case hot safely. The isolation transformer isolates it from ground completely. On 2/16/2012 10:10 PM, Greg Bogantz wrote: 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 philip_ca...@pittsford.monroe.edu To: Antique Phonograph List phono-l@oldcrank.org Sent: Thursday, February 16, 2012 8:45 PM Subject: Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_? 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 This email message and any attachments may contain confidential information. If you are not the intended recipient, you are prohibited from using the information in any way, including but not limited to disclosure of, copying, forwarding or acting in reliance on the contents. If you have received this email by error, please immediately notify me by return email and delete it from your email system. Thank you. ___ Phono-L mailing list http://phono-l.org ___ Phono-L mailing list http://phono-l.org This email message and any attachments may contain confidential information. If you are not the intended recipient, you are prohibited from using the information in any way, including but not limited to disclosure of, copying, forwarding or acting in reliance on the contents. If
Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_?
All this assumes the entire case is at the same potential. Then a shock occurs if you touch the case and something else that has a non infinite resistance to the other side of the line at the same time. An isolation transformer (not a variac or such) that completely isolates the item from the ground will remove the shock hazard caused by touching the case of the Motrola and ground. Nothing, including connecting the case to the green wire of the 3 wire plug will prevent a shock if all the metal is not at the same potential. If the case halves don't connect well, which can happen if it is cruddy potmetal you will still get a shock if you touch ground and the part that is not connected well to the part of the case you grounded. An isolation transformer will 100% prevent a shock unless you touch BOTH parts of a faulty case at the same time, and you will still get a shock if you grounded one part of the case in this case. The good thing about the isolation transformer is you don't have to make any changes to the Motrola and it can be used for other electronics when not using the phonograph. -Barry On 2/17/2012 10:51 AM, Bruce wrote: The isolation transformer does NOT make it safe. We use isolation transformers when working on TVs/Radios with a hot ground so that when we connect the ground lead of our instrumentation, we don't see fireworks. The isolation transformer allows the isolated circuit to float to whatever potential the leakage or forced paths take it. It is true that the only way to experience a shock is to come in contact with two significantly difference potentials. I think this discussion of shock hazards already had the premise that a potential near ground was available for accidental contact along with a faulty motrola. Bruce -Original Message- From: phono-l-boun...@oldcrank.org [mailto:phono-l-boun...@oldcrank.org] On Behalf Of Barry Kasindorf Sent: Friday, February 17, 2012 6:10 AM To: Antique Phonograph List Subject: Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_? Not true Greg. You would have to touch 2 different places with potential to get a shock and the case can't have that. Unless the isolation transformer is bad it makers it safe. That is how you can use those AC/DC sets with the case hot safely. The isolation transformer isolates it from ground completely. On 2/16/2012 10:10 PM, Greg Bogantz wrote: 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 philip_ca...@pittsford.monroe.edu To: Antique Phonograph Listphono-l@oldcrank.org Sent: Thursday, February 16, 2012 8:45 PM Subject: Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_? 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 Carliphilip_ca...@pittsford.monroe.edu To: Antique Phonograph Listphono-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
Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_?
There is no practical way to make these old devices absolutely idiot proof safe. Grounding the chassis and polarizing the power plug will at least open the power source after you experience a current flow to ground. The 3rd prong ground system may very well be defective and not protect the user. These items rely on the user understanding the hazards and taking the appropriate protective actions. Back about 50 years ago there was much research on the consequences of passing 60Hz currents through the human body and the end result was that between 5mA ans 100mA had the highest probability of causing death. This just happens to fall in the range of the nominal shock current resulting from contact with common household wall plug potential of 110v-125v. The major source of this research compilation was Tektronics Co. Those who served in the Navy may remember the training film 120 Volts, The Deadly Shipmate. Big SNIP ___ Phono-L mailing list http://phono-l.org
Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_?
Try it, Barry. I'll stand by and laugh. I just got a zap from a Fisher FM tuner that I routinely have plugged in to an isolation transformer (together with a variable AC transformer) as I do with all things on my workbench. Many old tube sets have capacitors from the line cord wiring to the chassis which can be pretty tickly, especially when these sets did not include the third chassis grounding wire in the line cord. I accidentally touched the output side of the Fisher transformer - that would be DOUBLE the isolation in place. 120 volts AC - or more - will bite you when you touch it, isolation xfmr or not. Isolation transformers are good for preventing large currents from flowing when you short things out which can blow fuses and start fires, but they don't do anything to reduce the voltage - that's what their purpose is. Greg - Original Message - From: Barry Kasindorf ba...@barrykasindorf.com To: Antique Phonograph List phono-l@oldcrank.org Sent: Friday, February 17, 2012 9:09 AM Subject: Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_? Not true Greg. You would have to touch 2 different places with potential to get a shock and the case can't have that. Unless the isolation transformer is bad it makers it safe. That is how you can use those AC/DC sets with the case hot safely. The isolation transformer isolates it from ground completely. On 2/16/2012 10:10 PM, Greg Bogantz wrote: 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 philip_ca...@pittsford.monroe.edu To: Antique Phonograph List phono-l@oldcrank.org Sent: Thursday, February 16, 2012 8:45 PM Subject: Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_? 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 This email message and any attachments may contain confidential information. If you are not the intended recipient, you are prohibited from using the information in any way, including but not limited to disclosure of, copying, forwarding or acting in reliance on the contents. If you have received this email by error, please immediately notify me by return email and delete it from your email system. Thank you. ___ Phono-L mailing list http://phono-l.org ___ Phono-L mailing list http://phono-l.org This email message and any attachments may contain confidential information. If you are not the intended recipient, you are prohibited
Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_?
Very true. The question was SAFETY. I hate having 3 wire plugs on antique electronics. You can easily put a polarized plug on a piece of zipcord and get the ends right and be safe as well. I like the idea of making something SAFE without changing the item at all. -Barry On 2/17/2012 12:25 PM, Bruce wrote: Barry, the shock hazard model during HiPot testing development assumes all external metallic surfaces on a product are always at the same potential. That is why we are only required to test against the product ground through an alligator clamp to the chassis or through the ground terminal of the 3 wire AC input. The shock hazard model we care about is a ground path through the body past the heart. You could be standing on a concrete floor barefoot or touching a cold water pipe with your other arm. I submit to you that I could connect any ungrounded electrical device through my isolation transformer, float it up to 1500VAC (the isolation voltage of my isolation transformer) and invite you to touch it and depending on your resistance to ground, you will definitely feel it. It will not be much current, and it may not kill you but it will wake you up faster than a few cups of coffee. Bruce Peterson Accolade Engineering www.accoladeeng.com -Original Message- From: phono-l-boun...@oldcrank.org [mailto:phono-l-boun...@oldcrank.org] On Behalf Of Barry Kasindorf Sent: Friday, February 17, 2012 8:28 AM To: Antique Phonograph List Subject: Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_? All this assumes the entire case is at the same potential. Then a shock occurs if you touch the case and something else that has a non infinite resistance to the other side of the line at the same time. An isolation transformer (not a variac or such) that completely isolates the item from the ground will remove the shock hazard caused by touching the case of the Motrola and ground. Nothing, including connecting the case to the green wire of the 3 wire plug will prevent a shock if all the metal is not at the same potential. If the case halves don't connect well, which can happen if it is cruddy potmetal you will still get a shock if you touch ground and the part that is not connected well to the part of the case you grounded. An isolation transformer will 100% prevent a shock unless you touch BOTH parts of a faulty case at the same time, and you will still get a shock if you grounded one part of the case in this case. The good thing about the isolation transformer is you don't have to make any changes to the Motrola and it can be used for other electronics when not using the phonograph. -Barry On 2/17/2012 10:51 AM, Bruce wrote: The isolation transformer does NOT make it safe. We use isolation transformers when working on TVs/Radios with a hot ground so that when we connect the ground lead of our instrumentation, we don't see fireworks. The isolation transformer allows the isolated circuit to float to whatever potential the leakage or forced paths take it. It is true that the only way to experience a shock is to come in contact with two significantly difference potentials. I think this discussion of shock hazards already had the premise that a potential near ground was available for accidental contact along with a faulty motrola. Bruce -Original Message- From: phono-l-boun...@oldcrank.org [mailto:phono-l-boun...@oldcrank.org] On Behalf Of Barry Kasindorf Sent: Friday, February 17, 2012 6:10 AM To: Antique Phonograph List Subject: Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_? Not true Greg. You would have to touch 2 different places with potential to get a shock and the case can't have that. Unless the isolation transformer is bad it makers it safe. That is how you can use those AC/DC sets with the case hot safely. The isolation transformer isolates it from ground completely. On 2/16/2012 10:10 PM, Greg Bogantz wrote: 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 philip_ca...@pittsford.monroe.edu To: Antique Phonograph Listphono-l@oldcrank.org Sent: Thursday, February 16, 2012 8:45 PM Subject: Re: [Phono-L] Does anyone know how to make a Jones Motrola _safe_? 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
Re: [Phono-L] Victor reproducer question
Steve: I sure would like 2 of the 1-56. In the event you have them for the other Victor reproducers,( if different than 1-56, 2 of each as well. . Please let me know Bob -Original Message- From: phono-l-boun...@oldcrank.org [mailto:phono-l-boun...@oldcrank.org] On Behalf Of Steven Medved Sent: Friday, February 17, 2012 6:17 AM To: phono-l@oldcrank.org Subject: Re: [Phono-L] Victor reproducer question 1-56 for the Exhibition. I am almost positive 1-72 on the 2, 4 and 5 Victor reproducers, I will double check unless someone else confirms. Do you need a 1-56 tap? I have some NOS ones. If a number of people want them I can put an order together as the cost will be under $2.50 for each one if they are still available. I like two, one I keep the point on and one I grind flat. I believe they are from the 1950's as they are deeply stamped. Steve From: maff...@bresnan.net To: phono-l@oldcrank.org Date: Thu, 16 Feb 2012 20:36:35 -0700 Subject: [Phono-L] Victor reproducer question Phono listers: What are the thread sizes for the thumb screw on: Victor: exhibition, n. 2, and 4a reproducers? again thanks Bob ___ Phono-L mailing list http://phono-l.org ___ Phono-L mailing list http://phono-l.org ___ Phono-L mailing list http://phono-l.org
Re: [Phono-L] Victor reproducer question
Steve, I would like 2 of the 1-56 taps. What size drill should be used in case you have to drill out a broken screw? Harvey Kravitz From: Bob Maffit maff...@bresnan.net To: 'Antique Phonograph List' phono-l@oldcrank.org Sent: Friday, February 17, 2012 2:25 PM Subject: Re: [Phono-L] Victor reproducer question Steve: I sure would like 2 of the 1-56. In the event you have them for the other Victor reproducers,( if different than 1-56, 2 of each as well. . Please let me know Bob -Original Message- From: phono-l-boun...@oldcrank.org [mailto:phono-l-boun...@oldcrank.org] On Behalf Of Steven Medved Sent: Friday, February 17, 2012 6:17 AM To: phono-l@oldcrank.org Subject: Re: [Phono-L] Victor reproducer question 1-56 for the Exhibition. I am almost positive 1-72 on the 2, 4 and 5 Victor reproducers, I will double check unless someone else confirms. Do you need a 1-56 tap? I have some NOS ones. If a number of people want them I can put an order together as the cost will be under $2.50 for each one if they are still available. I like two, one I keep the point on and one I grind flat. I believe they are from the 1950's as they are deeply stamped. Steve From: maff...@bresnan.net To: phono-l@oldcrank.org Date: Thu, 16 Feb 2012 20:36:35 -0700 Subject: [Phono-L] Victor reproducer question Phono listers: What are the thread sizes for the thumb screw on: Victor: exhibition, n. 2, and 4a reproducers? again thanks Bob ___ Phono-L mailing list http://phono-l.org ___ Phono-L mailing list http://phono-l.org ___ Phono-L mailing list http://phono-l.org ___ Phono-L mailing list http://phono-l.org
[Phono-L] Late Edison DD speed control
I recently saw a later Diamond Disc motor with a more complicated governor design than I usually see. The governor has what I guess is an anti-shock mechanism, three fingers with holes and pins in them which I am assuming work similarly to the spring wire on a Fireside governor. I could not figure out how one would change the speed of the motor. Can anyone enlighten me? Thanks, Ron L ___ Phono-L mailing list http://phono-l.org
Re: [Phono-L] Late Edison DD speed control
Hi Ron ~ The fingers are free to engage more deeply into the holes of the anti-shock collar as the weights expand and the flywheel is drawn inward. The collar limits undesirable rotation but does not limit compression of the distance between the flywheel and the opposite end of the governor shaft. Andrew Baron On Feb 17, 2012, at 7:36 PM, Ron L'Herault wrote: I recently saw a later Diamond Disc motor with a more complicated governor design than I usually see. The governor has what I guess is an anti-shock mechanism, three fingers with holes and pins in them which I am assuming work similarly to the spring wire on a Fireside governor. I could not figure out how one would change the speed of the motor. Can anyone enlighten me? Thanks, Ron L ___ Phono-L mailing list http://phono-l.org ___ Phono-L mailing list http://phono-l.org
