• Important Executive Director Announcement from the NAWCC

    The NAWCC Board of Directors is pleased to announce that Mr. Rory McEvoy has been named Executive Director of the NAWCC. Rory is an internationally renowned horological scholar and comes to the NAWCC with strong credentials that solidly align with our education, fundraising, and membership growth objectives. He has a postgraduate degree in the conservation and restoration of antique clocks from West Dean College, and throughout his career, he has had the opportunity to handle some of the world’s most important horological artifacts, including longitude timekeepers by Harrison, Kendall, and Mudge.

    Rory formerly worked as Curator of Horology at the Royal Observatory, Greenwich, where his role included day-to-day management of research and digitization projects, writing, public speaking, conservation, convening conferences, exhibition work, and development of acquisition/disposal and collection care policies. In addition, he has worked as a horological specialist at Bonhams in London, where he cataloged and handled many rare timepieces and built important relationships with collectors, buyers, and sellers. Most recently, Rory has used his talents to share his love of horology at the university level by teaching horological theory, history, and the practical repair and making of clocks and watches at Birmingham City University.

    Rory is a British citizen and currently resides in the UK. Pre-COVID-19, Rory and his wife, Kaai, visited HQ in Columbia, Pennsylvania, where they met with staff, spent time in the Museum and Library & Research Center, and toured the area. Rory and Kaai will be relocating to the area as soon as the immigration challenges and travel restrictions due to COVID-19 permit.

    Some of you may already be familiar with Rory as he is also a well-known author and lecturer. His recent publications include the book Harrison Decoded: Towards a Perfect Pendulum Clock, which he edited with Jonathan Betts, and the article “George Graham and the Orrery” in the journal Nuncius.

    Until Rory’s relocation to the United States is complete, he will be working closely with an on-boarding team assembled by the NAWCC Board of Directors to introduce him to the opportunities and challenges before us and to ensure a smooth transition. Rory will be participating in strategic and financial planning immediately, which will allow him to hit the ground running when he arrives in Columbia

    You can read more about Rory McEvoy and this exciting announcement in the upcoming March/April issue of the Watch & Clock Bulletin.

    Please join the entire Board and staff in welcoming Rory to the NAWCC community.

IBM IBM problem with slave clock stopping

berntd

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Jun 21, 2009
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Hello

I have ongoing issues with my master/ 1 slave IBM setup.

After trouble free operation for years, the slave clock has started misbehaving.

I find it stopped at 3 minutes past the hour whenever I look at it.

Next time I look, it will sit 3min past another hour and so on.

When I try to trouble shoot it with a multimeter, it works again and I am none the wiser.

What can this be?
The master clock 1min solenoid works correctly and it also follows the syncing pulses at the minute 59.

Best regards
Bernt
 

fdew

Registered User
Jul 12, 2007
235
4
18
Tell us more about the slave, or a picture of the movement.

Authentic is nice, but when I worked for Simplex I found that most issues were caused by correction, either in the master or in the slave. I have. A master in my home and 4 slaves. I run straight minute impulse t9 all of them.

BTW. I think correction was more of a sales tool then a feature for impulse clocks. They are ultra reliable until you add switch contacts, and extra pulses.
 

berntd

Registered User
Jun 21, 2009
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Where is Harold on this one?

Anyway, bottom line is that I do not hear the slave solenoid doing anything when it should.

The setup is such that all pulses are issued through a transistor controlled relay. I did that years ago to prevent the contacts in the master from wearing/migrating.
This still works fine as the master and accumulator solenoids operate correctly and I measure 24V pulses.

I am not sure about the B pulses as I write this.

Now the slave clock is the earlier style with the bigger brass movement and the solenoid with the seesaw lever.
When I try and measure at it, I do not find any faults. But then the whole thing just works again for some time.
Just long enough to pack away the equipment. And then BAM. I find it stopped again.

I have also seen it sit at minute 59.
But that might be normal because it is waiting for a B pulse to switch back to the A line.

I suspect a problem in the slave clock switchover contacts but the measure ok when I put the ohmmeter onto them.

Looks like I will have to add some indicator leds with zeners so they will indicate near 24V pulses.
It is a persistent problem.

1558830426211-375634343.jpg 1558830463305-880456770.jpg
 

Kevin W.

NAWCC Member
Apr 11, 2002
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Nepean, Ontario, Canada
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Harold Bain passed away last year.
 

berntd

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Jun 21, 2009
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Inspired by your reply, I just measured it all again.
The problem is the slave clock switch channel B. It has a bad contact in that only 15V get to the solenoid while on B pulses.

I just disassembled it and had a look. The contacts look ok as I cleaned them not long ago.

However, there might be too little preload spring tension on the contacts to work reliably.

The actuator lever has a bit of wear where it runs on the cams. Do I need to fix that or is it not relevant?

1558832431473-1918075260.jpg 15588324695711196521159.jpg 1558832505655116736365.jpg
 

berntd

Registered User
Jun 21, 2009
1,029
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Update:

It is the contact in the slave.
I jus disassembled and serviced it but I cannot fix it.
The contacts are suoer clean but if I switch them with the cams, they produce 25 to 200Ohm resistance on the B.
A is 0.7:^k.

How can I fix this? They neen more pressure but there is nothing there that can provide it.

15588369908592141912239.jpg 1558837053794-1193556202.jpg 1558837111590-1764351783.jpg
 

berntd

Registered User
Jun 21, 2009
1,029
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38
Sydney
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I have seen this fault before
The contact rivet on the switch can become oxidized
solution is to solder the back of the rivet to the spring part of the switch

Cheers
Edd
Hi Edd, that makes a lot of sense. I 'll do that as I cannot find any other explanation.

Regards
Bernt
 

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