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Restoration process of an Edison Class M phonograph


PedroFono

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Let me introduce myself. I'm Pedro Martinez, a Spanish IT engineer from Madrid. I started restoring gramophones, phonographs and organettes more than 20 years ago as a hobby – and it has since grown into a part-time profession (with the blessing of my wonderful wife and kids).

 

Since my early childhood, I have always had a screwdriver in my hand. I fixed toys, made all kinds of machines, built and restored my own cars – this was my way of expressing my creativity.

 

In the mid 90s, I found my first gramophone in the attic of a friend's house. The house was on the verge of collapsing, located in a small village in Spain, “Hiendelaencina.” Beside the machine was a pile of records, which is not unusual. But there were also some hand grenades and a Mauser rifle - my friend told me that nobody had touched any of this since the Spanish civil war. I still have that gramophone.

 

Since then, I have restored hundreds of machines, from humble suitcase portables to rare Bettinis - all of them restored with care and treated as unique pieces that have a story to tell us.

 

A few years ago, I started sharing on the various online forums and Facebook so other collectors could see my restorations. To my surprise, this attracted a lot of attention and now I am the proud owner of www.pedrofono.com

 

During this journey, I have met fantastic people and made very good friends who have stepped up to help me whenever I needed some support. 

 

And that brings me to the Edison Class M!

 

My good friend Eric Reiss, author of the book The Compleat Talking Machine, knew that I needed a challenging project to help me through a difficult personal situation. He found a wreck of an Edison Class M in Waco;TX (USA), bought it, and had it sent directly to me in Madrid for restoration. Imagine, Eric has never even seen the machine – yet!

 

Upon arrival, I carefully unboxed the machine, taking plenty of pictures to see if there was any damage caused during shipping. Fortunately, and thanks to the excellent packaging, everything arrived well. 

 

The machine came without case, dismantled and in a wood crating box. The box was old, which suggested that perhaps this very early machine was originally mounted in a desk, but moved to this box to preserve the machine when the desk became impractical.

 

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Upon inspection, my impression was that the machine had gone through many inexperienced hands that had tinkered and made lots of damage to it. I admit that this kind of situations are not bad news for me. I like the challenge of fixing the mistakes made by other restorers. Clearly, I was in for tons of hours of fun restoring it, so Eric had really found the perfect machine. Its serial number is 8822 so it is a pretty early machine, too.

 

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I took pictures of every piece, identified all of them, labeled, and classified them. After that, I made an in-depth assessment of all the works that needed to be done, missing pieces, and the estimation of time and cost. The list was two pages long.

 

Most importantly, I always take some time to think about and describe the vision I have for the restoration. It is an iterative process in which I study all the possibilities. During this exercise, the machine itself always starts to give hints about what is the correct thing to do. Here are some of the questions I ask myself:

 

  • What is the story behind this machine? 
  • What is its purpose in the future? 
  • Should I preserve its patina? 
  • How can I restore it and preserve its value yet also preserve its character and story? 
  • Is it fair to delete more than 120 years of story through repainting and replating?
  • What will another restorer in 100 years say about my work?
  • What is the opinion of the current owner? 

 

In this case, Eric and I were pretty much in agreement, so we only needed a short call before starting the restoration.

 

We opted to restore the machine while preserving its character. Very clean, all in perfect working order, showing its age but not its rust. As always, all the new pieces I will make will have my small "M" stamped in a discrete place. It is important for future owners to know if parts have been recently manufactured.

 

When starting such a big restoration, I prefer to begin with the most challenging things. In this case, it was the rotor of the motor. This Gramme Ring motor has four poles instead of the more common two poles. Moreover, the brushes are set at 90 degrees instead of 180. Finally, it works with only two to three DC volts – but somebody clearly tried to plug it to a much higher voltage and installed carbon brushes. The result was disastrous:  several internal wires melted and some of the coils were leaking electricity to the iron core. Happily, the old brushes were still in the bottom of the case, so I removed the carbon brushes and reassembled the arm with the old brushes – although I know that they are in such bad condition that they will eventually need to be replaced. At least the botched alterations were no longer hurting my eyes.

 

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I next removed the paraffin that covered all the interior of the rotor – and this was truly heartbreaking. There were melted wires everywhere and even burnt wood. This machine have been on the edge of starting a fire!. So, it was time to strip it down completely and start rewiring it. 40 coils, 40 internal bridges and 40 connections to the commutator. Even with my state of the art solder, it was a very challenging task.

 

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One of the most exciting things when working on this kind of restoration is finding documentation. You just cannot google "Wiring scheme Edison Class M phonograph" or "Gramme ring motor" and find it. On the other hand, it is now possible to reach in a matter of seconds people around the globe that can help you thanks to the many active collector groups on Facebook and beyond.

 

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Amazingly, my friend Wyatt Marcus (USA) had a scheme made by Mike Tucker and Graham Cavanagh-Downs (Australia) that answered some of my questions; others required a great deal more research in order to understand things.

When I was stumped, I asked my father (now retired but a former director of the IBM Scientific Center) to help me - he was instantly fully engaged in the project. Thanks to him, I was able to fully understand the physics behind these motors. He showed me how to apply a strict scientific approach to the problems in order to understand them. 

Eventually, we measured all the magnetic fields using a simple compass. We mapped them and finally understood what was not working.

 

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As I'm writing this lines, all the coils from the rotor and armature are working and I made new brushes. It's running but you will have to wait some days to see it. After fully testing it I will pour new paraffin inside the rotor.

 

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In the next installments of this article, I will describe the restoration of all the electric and mechanical parts, how I sourced mahogany wood to make a replica case, and other topics.

 

I look forward to sharing my thoughts and work with you and welcome any of your questions or comments on the restoration of this wonderful machine.

 

Regards,

 

Pedro Martínez

 

Edited by PedroFono
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About the Gramme ring motor

 

 

Zénobe Gramme (Belgian, 1826 - 1901) and his colleague Hippolyte Fontaine (French, 1833 - 1910), opened a factory to develop dynamos in 1871. The business, called Société des Machines Magnéto-Électriques Gramme, manufactured the Gramme dynamo, Gramme ring, Gramme armature, and other devices. 

 

In 1873 a Gramme dynamo was exhibited at the Vienna exhibition. Gramme accidentally discovered that this device, if supplied with a constant-voltage power supply, acted as an electric motor when Hippolyte Fontaine accidentally connected the terminals of a Gramme machine to another dynamo, which was producing electricity. To Gramme’s surprise, the shaft began to spin.

 

The Gramme machine was the first useful electric motor that was powerful enough to be successful in industry. In fact, it became the basis for all direct-current electric motors - and made it possible for Thomas Edison and Nikola Tesla to create their subsequent inventions.

 

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Edited by PedroFono
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RodPickett

Pedro

 

Welcome to the Forum.

 

This is an excellent start and we look forward to your contributions.

 

rod

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Pedro,  Very very interesting article.  I look forward to subsequent additions and of course to see the final result.

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Very well put together article. Nice work and great images.

Edited by melvind
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Auxetophone

Pedro, having seen some of your other highly detailed restorations, I am very much looking forward to seeing the finished product on this Class M! 

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Pedro, welcome to the APS Forum!

 

I have read your posts elsewhere, and marveled at your results.  In this particular post, you have made plain what experienced collectors/restorers have learned over the years.  It takes patience, thoughtfulness, collaboration when necessary, and respect for the artifact (in addition to skill) to perform even a simple restoration.  Those of us with limitations must recognize them and enlist the help of others when necessary.  You are the "poster boy" for how antique phonograph restorations should be approached.  It's a pleasure to have you here!

 

By the way, I especially like your question: "What will another restorer in 100 years say about my work?"

 

You and my friend Eric are to be commended for saving this Class M.?

 

George P.

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Welcome Pedro, and thank you for your most interesting inaugural post. A class M is only a dream for me, but nonetheless I'm captivated by them, so seeing the details of the motor that you've included here are especially interesting!

 

Cheers,

Fran

 

 

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Pedro-

 

Great post on your Class M.  I can relate to what you are going thru.  A couple of years ago, I acquired a Class M that needed quite a bit of restoration, but I didn't have to rewind the armature as you are.  Wow, what a task that must be.

 

Here's before and after photos of my Class M's bedplate and motor.  Keep me posted as to your progress.  I'd like to hear how it runs after you are done because mine runs just a tad slow.  Haven't had time to figure out why, but I will.

 

Mark

Class M Existing - 01.jpg

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Class M Mechanism-07a.jpg

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On 6/8/2020 at 7:12 PM, Phonomark said:

 

Here's before and after photos of my Class M's bedplate and motor.  

 

That is absolutely Gorgeous, you did a fantastic job on that. 

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  • 3 weeks later...
  • 4 years later...

hi,

 

Could you give me your contact information.  I have a Class M in trouble.

 

Ken Danckaert

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PedroFono

Hi Ken. Drop me a line to info.pedrofono@gmail.com or WhatsApp +34 639 19 72 08

 

Regards

 

Pedro Martínez 

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