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.
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...

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!


From: <> on behalf of Brooke Clarke via <brooke@...>
Sent: 30 July 2021 16:23
To: <>
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:

Have Fun,

Brooke Clarke
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.

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