Date   

Synchronome to Resurrect

Grant Griffiths
 

Dear All,

I have been donated a Synchronome which came in 2 plastic bags and a back plate - so hours of fun ahead.  Not too surprisingly the parts don't match: the pivots on the wheel, detent and latch are 1.5mm and the bushes are ~1.2mm.  the reverse is true on the contact arm pivots. The rest of it is pretty straightforward, clean, de-rust, rewire, new pads and set-up.

The parts include an NRA plate and lever but the plate is not tapped for it - I can donate those to a friend who does have a plate tapped for them.   There are also other left-over parts (left hand side of the photo).  My intention would be to re-bush the plates to fit the parts I have - not ideal, but better to resurrect it than continue as bags of bits.  Not a huge pool of parts here in Oz.  There is no serial number on the contact arm plate.

My questions are: can anyone provide background on the two pivot sizes - date, etc., and also dimensions of the suspension spring - I have a 0.1mm piece of the correct width, but I don't know the correct gap between the blocks?  I will be modifying a chrome-plated IBM master clock pendulum, that came with it, that should work.  It has a Invar rod, but the colour scheme is hardly an exact match.  When completed the clock will go in a grandmother case I inherited that had the Hipp toggle movement replaced with quartz about 30 years ago.  The dimensions are suitable.

I have the gap set-up sheet and wiring diagram.

Best regards,

Grant


Re: sticking reset

H Hal
 

Hold a square file (tapered) in a vice so it is pointing upwards, and slip the hand square onto the file snugly.

The collet is now secure, using both your hands hold the min hand around the collet seat and hand at the same time.

Gently turn the hand, the collet stays put but you should get some movement of the hand....and the collet stays pretty firm with no need to rivet/glue afterwards, unless the rivet has been loosened.


The main point is not to turn the hand via the hand where it may break at the root but turn by the collet surround


fingers crossed


hal

uk

On 06/08/2021 23:31, John Howell wrote:
Ian,
One thing that has puzzled me is having set up the impulsing correctly how do you get the minute hand to land accurately on the dial battons? The hand sits on a square on the minute arbor and is imovable unless it is re-riveted.

Regards,
John H.

On 4 Aug 2021, at 22:06, Ian Richardson via groups.io <irichar361@...> wrote:

Eric,

A further point to note is that with Synchronome slave movements, the armature should ideally not touch the magnet pole face as there is an adjustable back stop.  However, the adjustment of the back stop is best used to limit the pawl to gather only one tooth of the 120 tooth wheel.  If you're lucky, that also prevents the armature from touching the pole piece, but very often a piece of paper is glued to the armature face just in case!

Cheers,
Ian R



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Wed, 4 Aug 2021 16:32
Subject: Re: [synchronomeelectricclock] sticking reset

Thanks, Ian. You are right about the settings preventing contact — I had overlooked that. It was the slave moment that I was remembering...

On 2021 Aug 02, at 18:10 , Ian Richardson via groups.io <irichar361@...> wrote:

What you say is correct, but shouldn't be necessary as there is a buffer which limits the proximity of the armature to the pole pieces.  In my previous posting with a sketch of the settings, I mentioned as Stage 1 the setting of this as 0.01".  If this setting is correct, the armature should never make contact with the pole pieces, rendering the piece of paper unnecessary.

In the slave movements, it was common for a piece of paper to cover the face of the pole piece. In PO 3000 type relays, a brass stud was fitted to the pole face to achieve the same effect.

Best regards,

Ian R
Auvergne, France



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Mon, 2 Aug 2021 23:17
Subject: [synchronomeelectricclock] sticking reset

  The coil pole face should be covered with a piece of paper or electrical tape. This helps prevent the armature from sticking to the pole face due to residual magnetism.

  I’ve had good results with a circular piece of paper cut from the sticky part of a Post-It note, or from black electrical tape, using a paper hole punch as a replacement for what covered the pole face originally.

On 2021 Jul 30, at 08:22 , Andrew Nahum <andrew.nahum@...> wrote:

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments.


Re: sticking reset

klopschip
 

Hello John and Ian,

Usually the brass bushing in a minutes hand is riveted and can be rotated although this takes some force. I usually use a small square file in the vice and with trial and error get the tip on the battons. Actually, same goes to get the minutes hand of any clock to point at "12" when stricking the hour.

All the best
Bart

On Saturday, August 7, 2021, 1:25:13 AM GMT+2, Ian Richardson via groups.io <irichar361@...> wrote:


John,

Good point.  I haven't encountered that problem often, but seem to recall that the brass bush with the square hole can be moved slightly within the hand and then secured in place with a drop of Super Glue applied from behind (out of sight).  As it happens, the pilot dial on one of my Synchronomes does exhibit a slight misalignment, but I've sort of got used to it!

Others may have other ideas.

Best regards,
Ian



-----Original Message-----
From: John Howell <j@...>
To: synchronome1@groups.io
Sent: Sat, 7 Aug 2021 0:31
Subject: Re: [synchronomeelectricclock] sticking reset

Ian,
One thing that has puzzled me is having set up the impulsing correctly how do you get the minute hand to land accurately on the dial battons? The hand sits on a square on the minute arbor and is imovable unless it is re-riveted.

Regards,
John H.

On 4 Aug 2021, at 22:06, Ian Richardson via groups.io <irichar361@...> wrote:

Eric,

A further point to note is that with Synchronome slave movements, the armature should ideally not touch the magnet pole face as there is an adjustable back stop.  However, the adjustment of the back stop is best used to limit the pawl to gather only one tooth of the 120 tooth wheel.  If you're lucky, that also prevents the armature from touching the pole piece, but very often a piece of paper is glued to the armature face just in case!

Cheers,
Ian R



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Wed, 4 Aug 2021 16:32
Subject: Re: [synchronomeelectricclock] sticking reset

Thanks, Ian. You are right about the settings preventing contact — I had overlooked that. It was the slave moment that I was remembering...

On 2021 Aug 02, at 18:10 , Ian Richardson via groups.io <irichar361@...> wrote:

What you say is correct, but shouldn't be necessary as there is a buffer which limits the proximity of the armature to the pole pieces.  In my previous posting with a sketch of the settings, I mentioned as Stage 1 the setting of this as 0.01".  If this setting is correct, the armature should never make contact with the pole pieces, rendering the piece of paper unnecessary.

In the slave movements, it was common for a piece of paper to cover the face of the pole piece. In PO 3000 type relays, a brass stud was fitted to the pole face to achieve the same effect.

Best regards,

Ian R
Auvergne, France



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Mon, 2 Aug 2021 23:17
Subject: [synchronomeelectricclock] sticking reset

  The coil pole face should be covered with a piece of paper or electrical tape. This helps prevent the armature from sticking to the pole face due to residual magnetism.

  I’ve had good results with a circular piece of paper cut from the sticky part of a Post-It note, or from black electrical tape, using a paper hole punch as a replacement for what covered the pole face originally.

On 2021 Jul 30, at 08:22 , Andrew Nahum <andrew.nahum@...> wrote:

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments.


Re: sticking reset

Ian Richardson
 

John,

Good point.  I haven't encountered that problem often, but seem to recall that the brass bush with the square hole can be moved slightly within the hand and then secured in place with a drop of Super Glue applied from behind (out of sight).  As it happens, the pilot dial on one of my Synchronomes does exhibit a slight misalignment, but I've sort of got used to it!

Others may have other ideas.

Best regards,
Ian



-----Original Message-----
From: John Howell <j@...>
To: synchronome1@groups.io
Sent: Sat, 7 Aug 2021 0:31
Subject: Re: [synchronomeelectricclock] sticking reset

Ian,
One thing that has puzzled me is having set up the impulsing correctly how do you get the minute hand to land accurately on the dial battons? The hand sits on a square on the minute arbor and is imovable unless it is re-riveted.

Regards,
John H.

On 4 Aug 2021, at 22:06, Ian Richardson via groups.io <irichar361@...> wrote:

Eric,

A further point to note is that with Synchronome slave movements, the armature should ideally not touch the magnet pole face as there is an adjustable back stop.  However, the adjustment of the back stop is best used to limit the pawl to gather only one tooth of the 120 tooth wheel.  If you're lucky, that also prevents the armature from touching the pole piece, but very often a piece of paper is glued to the armature face just in case!

Cheers,
Ian R



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Wed, 4 Aug 2021 16:32
Subject: Re: [synchronomeelectricclock] sticking reset

Thanks, Ian. You are right about the settings preventing contact — I had overlooked that. It was the slave moment that I was remembering...

On 2021 Aug 02, at 18:10 , Ian Richardson via groups.io <irichar361@...> wrote:

What you say is correct, but shouldn't be necessary as there is a buffer which limits the proximity of the armature to the pole pieces.  In my previous posting with a sketch of the settings, I mentioned as Stage 1 the setting of this as 0.01".  If this setting is correct, the armature should never make contact with the pole pieces, rendering the piece of paper unnecessary.

In the slave movements, it was common for a piece of paper to cover the face of the pole piece. In PO 3000 type relays, a brass stud was fitted to the pole face to achieve the same effect.

Best regards,

Ian R
Auvergne, France



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Mon, 2 Aug 2021 23:17
Subject: [synchronomeelectricclock] sticking reset

  The coil pole face should be covered with a piece of paper or electrical tape. This helps prevent the armature from sticking to the pole face due to residual magnetism.

  I’ve had good results with a circular piece of paper cut from the sticky part of a Post-It note, or from black electrical tape, using a paper hole punch as a replacement for what covered the pole face originally.

On 2021 Jul 30, at 08:22 , Andrew Nahum <andrew.nahum@...> wrote:

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments.


Re: sticking reset

John Howell
 

Ian,
One thing that has puzzled me is having set up the impulsing correctly how do you get the minute hand to land accurately on the dial battons? The hand sits on a square on the minute arbor and is imovable unless it is re-riveted.

Regards,
John H.

On 4 Aug 2021, at 22:06, Ian Richardson via groups.io <irichar361@...> wrote:

Eric,

A further point to note is that with Synchronome slave movements, the armature should ideally not touch the magnet pole face as there is an adjustable back stop.  However, the adjustment of the back stop is best used to limit the pawl to gather only one tooth of the 120 tooth wheel.  If you're lucky, that also prevents the armature from touching the pole piece, but very often a piece of paper is glued to the armature face just in case!

Cheers,
Ian R



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Wed, 4 Aug 2021 16:32
Subject: Re: [synchronomeelectricclock] sticking reset

Thanks, Ian. You are right about the settings preventing contact — I had overlooked that. It was the slave moment that I was remembering...

On 2021 Aug 02, at 18:10 , Ian Richardson via groups.io <irichar361@...> wrote:

What you say is correct, but shouldn't be necessary as there is a buffer which limits the proximity of the armature to the pole pieces.  In my previous posting with a sketch of the settings, I mentioned as Stage 1 the setting of this as 0.01".  If this setting is correct, the armature should never make contact with the pole pieces, rendering the piece of paper unnecessary.

In the slave movements, it was common for a piece of paper to cover the face of the pole piece. In PO 3000 type relays, a brass stud was fitted to the pole face to achieve the same effect.

Best regards,

Ian R
Auvergne, France



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Mon, 2 Aug 2021 23:17
Subject: [synchronomeelectricclock] sticking reset

  The coil pole face should be covered with a piece of paper or electrical tape. This helps prevent the armature from sticking to the pole face due to residual magnetism.

  I’ve had good results with a circular piece of paper cut from the sticky part of a Post-It note, or from black electrical tape, using a paper hole punch as a replacement for what covered the pole face originally.

On 2021 Jul 30, at 08:22 , Andrew Nahum <andrew.nahum@...> wrote:

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments.


Re: sticking reset

Ian Richardson
 

Eric,

A further point to note is that with Synchronome slave movements, the armature should ideally not touch the magnet pole face as there is an adjustable back stop.  However, the adjustment of the back stop is best used to limit the pawl to gather only one tooth of the 120 tooth wheel.  If you're lucky, that also prevents the armature from touching the pole piece, but very often a piece of paper is glued to the armature face just in case!

Cheers,
Ian R



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Wed, 4 Aug 2021 16:32
Subject: Re: [synchronomeelectricclock] sticking reset

Thanks, Ian. You are right about the settings preventing contact — I had overlooked that. It was the slave moment that I was remembering...

On 2021 Aug 02, at 18:10 , Ian Richardson via groups.io <irichar361@...> wrote:

What you say is correct, but shouldn't be necessary as there is a buffer which limits the proximity of the armature to the pole pieces.  In my previous posting with a sketch of the settings, I mentioned as Stage 1 the setting of this as 0.01".  If this setting is correct, the armature should never make contact with the pole pieces, rendering the piece of paper unnecessary.

In the slave movements, it was common for a piece of paper to cover the face of the pole piece. In PO 3000 type relays, a brass stud was fitted to the pole face to achieve the same effect.

Best regards,

Ian R
Auvergne, France



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Mon, 2 Aug 2021 23:17
Subject: [synchronomeelectricclock] sticking reset

  The coil pole face should be covered with a piece of paper or electrical tape. This helps prevent the armature from sticking to the pole face due to residual magnetism.

  I’ve had good results with a circular piece of paper cut from the sticky part of a Post-It note, or from black electrical tape, using a paper hole punch as a replacement for what covered the pole face originally.

On 2021 Jul 30, at 08:22 , Andrew Nahum <andrew.nahum@...> wrote:

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments.


Re: sticking reset

Eric Scace
 

Thanks, Ian. You are right about the settings preventing contact — I had overlooked that. It was the slave moment that I was remembering...

On 2021 Aug 02, at 18:10 , Ian Richardson via groups.io <irichar361@...> wrote:

What you say is correct, but shouldn't be necessary as there is a buffer which limits the proximity of the armature to the pole pieces.  In my previous posting with a sketch of the settings, I mentioned as Stage 1 the setting of this as 0.01".  If this setting is correct, the armature should never make contact with the pole pieces, rendering the piece of paper unnecessary.

In the slave movements, it was common for a piece of paper to cover the face of the pole piece. In PO 3000 type relays, a brass stud was fitted to the pole face to achieve the same effect.

Best regards,

Ian R
Auvergne, France



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Mon, 2 Aug 2021 23:17
Subject: [synchronomeelectricclock] sticking reset

  The coil pole face should be covered with a piece of paper or electrical tape. This helps prevent the armature from sticking to the pole face due to residual magnetism.

  I’ve had good results with a circular piece of paper cut from the sticky part of a Post-It note, or from black electrical tape, using a paper hole punch as a replacement for what covered the pole face originally.

On 2021 Jul 30, at 08:22 , Andrew Nahum <andrew.nahum@...> wrote:

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments.


Re: sticking reset

Ian Richardson
 

What you say is correct, but shouldn't be necessary as there is a buffer which limits the proximity of the armature to the pole pieces.  In my previous posting with a sketch of the settings, I mentioned as Stage 1 the setting of this as 0.01".  If this setting is correct, the armature should never make contact with the pole pieces, rendering the piece of paper unnecessary.

In the slave movements, it was common for a piece of paper to cover the face of the pole piece. In PO 3000 type relays, a brass stud was fitted to the pole face to achieve the same effect.

Best regards,

Ian R
Auvergne, France



-----Original Message-----
From: Eric Scace <eric@...>
To: synchronome <synchronome1@groups.io>
Sent: Mon, 2 Aug 2021 23:17
Subject: [synchronomeelectricclock] sticking reset

  The coil pole face should be covered with a piece of paper or electrical tape. This helps prevent the armature from sticking to the pole face due to residual magnetism.

  I’ve had good results with a circular piece of paper cut from the sticky part of a Post-It note, or from black electrical tape, using a paper hole punch as a replacement for what covered the pole face originally.

On 2021 Jul 30, at 08:22 , Andrew Nahum <andrew.nahum@...> wrote:

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments.


Re: sticking reset

Andrew Nahum
 

Good tip - I think you’ve put your finger on it. In my case the sticking certainly felt magnetic. Suggested by the way the grip let go as soon as the gravity arm was pulled away by a quarter of a millimetre or so. When I’m being good I set all the gaps with automotive feeler gauges or measured drill shanks for the larger ones. 


On 2 Aug 2021, at 22:17, Eric Scace <eric@...> wrote:

  The coil pole face should be covered with a piece of paper or electrical tape. This helps prevent the armature from sticking to the pole face due to residual magnetism.

  I’ve had good results with a circular piece of paper cut from the sticky part of a Post-It note, or from black electrical tape, using a paper hole punch as a replacement for what covered the pole face originally.

On 2021 Jul 30, at 08:22 , Andrew Nahum <andrew.nahum@...> wrote:

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments.


sticking reset

Eric Scace
 

  The coil pole face should be covered with a piece of paper or electrical tape. This helps prevent the armature from sticking to the pole face due to residual magnetism.

  I’ve had good results with a circular piece of paper cut from the sticky part of a Post-It note, or from black electrical tape, using a paper hole punch as a replacement for what covered the pole face originally.

On 2021 Jul 30, at 08:22 , Andrew Nahum <andrew.nahum@...> wrote:

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments.


Nick Maag

James Nye
 

Dear Friends,

Please forgive the same post across a few groups. I know some of you will already have heard the very sad news, but for those who have not, I am sorry to say that we lost Nick Maag at the weekend. His very good friend Arturo Pedrini, a close neighbour in Switzerland, let some of us know that Nick suffered a brain haemorrhage at the end of last week, following which he was immediately hospitalized, but he died on Saturday. He is a very great loss to the horological community. An Anglophile who spent part of the 1960s working in the UK, he enjoyed travelling greatly, and was fluent across a wide variety of languages, making friends across Europe and the United States. Many of us probably saw him most regularly at annual gatherings in Mannheim, usually in the Spring. He was one of the old faithfuls of that meeting, there from the early days. He assisted the gathering together of a lot of material that has been digitised by our good friends in the DGC, and he was also a key figure in Chronometrophilia.

Many of us will have very fond memories of jovial meals and energetic conversation with Nick there in the midst of it all. Raise a glass when you can.

All the very best,

James

 


Re: Sticking reset

Brian Cracknell
 

Thank you all for your suggestions and advice over the past day. 

Based on the advice I have done the following actions:

1. Reset all the gaps to the specified settings. The clock would still not work correctly even after this. 

2. Removed and cleaned the platinum contacts. This also made no improvement. 

3. Bypassed an original, dodgy variable resistor in the cabinet which had previously been set to zero anyway and made good the connection. This did not improve things. 

4. Double-checked all connections inside the cabinet. Nothing loose was discovered. 

5. Examined an in-line fuse which I had installed a long time ago between the power source and the clock. One connection was loose. This was fixed and the clock started working correctly. 

Here is a link to the new Youtube video showing the far more satisfying clunk that now occurs. 

https://youtu.be/bOG0l323SjE
Following the expert analysis and suggestions on the Synchronome forum regarding the fault shown on the previous video, I made the following adjustments:1. R...
youtu.be

This clunk is the crispest for a long time and is mainly due to restoring the correct settings for the contact gaps, etc. From time to time I have restored these defaults but the temptation to fiddle has often proved too strong to resist and over time the settings have drifted somewhat. The main reason for this I now recall, has been to try to minimise pendulum shimmer at the moment of impulse by varying the amount of time the roller is on the pallet. Inevitably that takes you away from the precise specified settings.

So all the advice proved to be spot-on. Setting up as per instructions, searching for an electrical conductivity issue, etc.

Thanks again all!

Regards
Brian




From: synchronome1@groups.io <synchronome1@groups.io> on behalf of Brooke Clarke via groups.io <brooke@...>
Sent: 30 July 2021 16:23
To: synchronome1@groups.io <synchronome1@groups.io>
Subject: Re: [synchronomeelectricclock] Sticking reset
 
Hi Brian:

The sluggishness of the movement indicates that you are driving the clock with the minimum voltage needed to get the
correct current based on the coil resistance.  You will get much snappier performance, i.e. more solid operation if the
loop voltage is 5 to 10 times higher which requires the addition of a carbon resistor in order to maintain the correct
current.  Technically you are lowering the loop time constant since T = L/R.  For example see this test where a
capacitor is charged to a known voltage then applied to the coil through a resistor chosen so that the coil current is
the nominal value: https://youtu.be/wwFhpL7JEk4

--
Have Fun,

Brooke Clarke
https://www.PRC68.com
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.







Re: Sticking reset

Brooke Clarke
 

Hi Brian:

The sluggishness of the movement indicates that you are driving the clock with the minimum voltage needed to get the correct current based on the coil resistance.  You will get much snappier performance, i.e. more solid operation if the loop voltage is 5 to 10 times higher which requires the addition of a carbon resistor in order to maintain the correct current.  Technically you are lowering the loop time constant since T = L/R.  For example see this test where a capacitor is charged to a known voltage then applied to the coil through a resistor chosen so that the coil current is the nominal value: https://youtu.be/wwFhpL7JEk4

--
Have Fun,

Brooke Clarke
https://www.PRC68.com
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.


Re: Sticking reset

Andrew Nahum
 

I have had similar sticking on occasion. It seemed to be an electromagnetic phenomenon that developed because the ‘dwell’ of the closed contacts was too long. I have found over the years that  it’s always best to check or re-set all the gaps or clearances in the mechanism rather than use intuition to try and address a problem with particular adjustments. 


On 29 Jul 2021, at 22:23, John Hubert <jfphubert@...> wrote:

The correct adjustments are given here;



On 29 Jul 2021, at 22:09, Brian Cracknell <brcracknell@...> wrote:

Hello, I am having issues with my clock again. It runs fine for a while and then starts sticking as shown in this Youtube video (link below). The armature does not get grabbed by the coils properly when it should be impulsed leading to the ugly delay evident in the video which has adverse effects on timekeeping.

The current in the system is set to 330mA. Everything is clean; I have tried two separate power sources with the same result. I am currently using a mains plug-in transformer/rectifier running at 4.5 volts output with appropriate resistors. 

Previously I have fixed this issue by adjusting the backstop screw for the armature to being it closer to the coils and also adjusting the contact screw to move that the other way to keep the gap constant. That worked for a while but now the fault has reoccured. I always make sure that the screws are tightly locked in place after each adjustment so I do not think they are wobbling and reverting to a bad state.

Frustratingly, the "stickiness" may well disappear for a while the following day without any intervention and the gravity arm reverts to a healthy briskness in its reset. The improvement is generally short lived.

I would welcome any opinions.

https://youtu.be/cExBOStyNdU

Thanks 
Brian


Re: Sticking reset

H Hal
 

My first thought is one of poor electrical contact, are the contacts in good order..polished and clean, not cleaned with any abrasive wet/dry etc but clean, no oxidation.


I would then remove the pendulum and lower the gravity arm by hand very slowly to see if it makes contact and how well it makes contact...you can measure the current whilst doing this to see if it is reduced


is your current limited by a rheostat?  these also have contacts which may be in need of cleaning



hal

uk

On 29/07/2021 22:09, Brian Cracknell wrote:
Hello, I am having issues with my clock again. It runs fine for a while and then starts sticking as shown in this Youtube video (link below). The armature does not get grabbed by the coils properly when it should be impulsed leading to the ugly delay evident in the video which has adverse effects on timekeeping.

The current in the system is set to 330mA. Everything is clean; I have tried two separate power sources with the same result. I am currently using a mains plug-in transformer/rectifier running at 4.5 volts output with appropriate resistors. 

Previously I have fixed this issue by adjusting the backstop screw for the armature to being it closer to the coils and also adjusting the contact screw to move that the other way to keep the gap constant. That worked for a while but now the fault has reoccured. I always make sure that the screws are tightly locked in place after each adjustment so I do not think they are wobbling and reverting to a bad state.

Frustratingly, the "stickiness" may well disappear for a while the following day without any intervention and the gravity arm reverts to a healthy briskness in its reset. The improvement is generally short lived.

I would welcome any opinions.

https://youtu.be/cExBOStyNdU

Thanks 
Brian


Re: Sticking reset

Ian Richardson
 

Hi Brian,

There is an ancient proverb which says, "if all else fails, read the instructions".

Others may contribute, but for a start I attach a pdf file of a sketch I made years ago showing the settings for the buffers, air gaps etc.  As your current seems to be correct, maybe you could try adjusting these settings.

The only other thing is to try slackening the gravity arm return spring.  Finally, make sure that the rest buffer is clean and that the armature isn't sticking to it.  Other than that, I've noting more to offer.

Good luck,
Ian R
Auvergne, France


-----Original Message-----
From: Brian Cracknell <brcracknell@...>
To: synchronome1@groups.io
Sent: Thu, 29 Jul 2021 23:09
Subject: [synchronomeelectricclock] Sticking reset

Hello, I am having issues with my clock again. It runs fine for a while and then starts sticking as shown in this Youtube video (link below). The armature does not get grabbed by the coils properly when it should be impulsed leading to the ugly delay evident in the video which has adverse effects on timekeeping.

The current in the system is set to 330mA. Everything is clean; I have tried two separate power sources with the same result. I am currently using a mains plug-in transformer/rectifier running at 4.5 volts output with appropriate resistors. 

Previously I have fixed this issue by adjusting the backstop screw for the armature to being it closer to the coils and also adjusting the contact screw to move that the other way to keep the gap constant. That worked for a while but now the fault has reoccured. I always make sure that the screws are tightly locked in place after each adjustment so I do not think they are wobbling and reverting to a bad state.

Frustratingly, the "stickiness" may well disappear for a while the following day without any intervention and the gravity arm reverts to a healthy briskness in its reset. The improvement is generally short lived.

I would welcome any opinions.

https://youtu.be/cExBOStyNdU

Thanks 
Brian


Re: Sticking reset

John Hubert
 

On 29 Jul 2021, at 22:09, Brian Cracknell <brcracknell@...> wrote:

Hello, I am having issues with my clock again. It runs fine for a while and then starts sticking as shown in this Youtube video (link below). The armature does not get grabbed by the coils properly when it should be impulsed leading to the ugly delay evident in the video which has adverse effects on timekeeping.

The current in the system is set to 330mA. Everything is clean; I have tried two separate power sources with the same result. I am currently using a mains plug-in transformer/rectifier running at 4.5 volts output with appropriate resistors. 

Previously I have fixed this issue by adjusting the backstop screw for the armature to being it closer to the coils and also adjusting the contact screw to move that the other way to keep the gap constant. That worked for a while but now the fault has reoccured. I always make sure that the screws are tightly locked in place after each adjustment so I do not think they are wobbling and reverting to a bad state.

Frustratingly, the "stickiness" may well disappear for a while the following day without any intervention and the gravity arm reverts to a healthy briskness in its reset. The improvement is generally short lived.

I would welcome any opinions.

https://youtu.be/cExBOStyNdU

Thanks 
Brian


Sticking reset

Brian Cracknell
 

Hello, I am having issues with my clock again. It runs fine for a while and then starts sticking as shown in this Youtube video (link below). The armature does not get grabbed by the coils properly when it should be impulsed leading to the ugly delay evident in the video which has adverse effects on timekeeping.

The current in the system is set to 330mA. Everything is clean; I have tried two separate power sources with the same result. I am currently using a mains plug-in transformer/rectifier running at 4.5 volts output with appropriate resistors. 

Previously I have fixed this issue by adjusting the backstop screw for the armature to being it closer to the coils and also adjusting the contact screw to move that the other way to keep the gap constant. That worked for a while but now the fault has reoccured. I always make sure that the screws are tightly locked in place after each adjustment so I do not think they are wobbling and reverting to a bad state.

Frustratingly, the "stickiness" may well disappear for a while the following day without any intervention and the gravity arm reverts to a healthy briskness in its reset. The improvement is generally short lived.

I would welcome any opinions.

https://youtu.be/cExBOStyNdU

Thanks 
Brian


Re: M4 Turret movement resistor puzzle.

Peter Torry
 

When switching high current and or inductive loads it was usual to fit a mercury switch as then can cope with most "nasty" loads particularly when breaking high currents.  They were also fitted in order to stretch the impulse to  the turret movements to allow sufficient time for the slower movement to operate correctly.  If it is of help I can post an image of one - when I can find my camera !

Regards

Peter


On 26/07/2021 20:21, John Hubert wrote:
Two points here.  Firstly Robert (Bob) Miles book was compiled from the material he had available.  There are quite limited records for Synchronome.  It is possible he worked mainly from the hardware he had access to rather than detailed drawings and specifications.

Secondly, the ’norm’ (Synchronome) is to have resistor approximately 10 times the resistance of the coil in parallel for spark suppression.  Possibly that was fitted in your case.  Do you know the coil resistance?

I believe (and someone will no doubt correct me if I am wrong) that it was common in later days to have an “mercury delay” for big dial movements - and this may have removed the worry over sparks?

On 26 Jul 2021, at 19:53, Simon Allen <simon.sallen@...> wrote:

I am seeking to restore an M4 turret movement.  Robert Miles in his book says that it did not have a resistor connected in parallel with the coil.  My one does.  Across the two terminals connected in parallel to the coil is a 250 ohm resistor.  What was its purpose?


Re: M4 Turret movement resistor puzzle.

John Hubert
 

As a further thought, is it possible that the large movements - that would be installed very often large existing dials might have the resistor fitted by the installer when completing the installation, rather than fitted to the movement prior to delivery?

On 26 Jul 2021, at 20:21, John Hubert via groups.io <jfphubert@...> wrote:

Two points here.  Firstly Robert (Bob) Miles book was compiled from the material he had available.  There are quite limited records for Synchronome.  It is possible he worked mainly from the hardware he had access to rather than detailed drawings and specifications.

Secondly, the ’norm’ (Synchronome) is to have resistor approximately 10 times the resistance of the coil in parallel for spark suppression.  Possibly that was fitted in your case.  Do you know the coil resistance?

I believe (and someone will no doubt correct me if I am wrong) that it was common in later days to have an “mercury delay” for big dial movements - and this may have removed the worry over sparks?

On 26 Jul 2021, at 19:53, Simon Allen <simon.sallen@...> wrote:

I am seeking to restore an M4 turret movement.  Robert Miles in his book says that it did not have a resistor connected in parallel with the coil.  My one does.  Across the two terminals connected in parallel to the coil is a 250 ohm resistor.  What was its purpose?


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