• 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.

Need a little help with Kundo

Tony10Clocks

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Aug 10, 2010
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Hello. I got this Kundo Electronic today, hoping to restore it. and need a little help.......

1, What size suspension spring would i need.
2, Looking at the photo's could you tell me what could be missing
3, Where could i get a dome for it from

I think it still has the original battery in it. And it looks like there something missing underneath next to the battery.
Cheers
Tony
-> posts merged by system <-
Forgot the pics
-> posts merged by system <-
Try again :D
 

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eskmill

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The suspension spring assembly required is Meadows & Passmore number 0672 000115. It is specially made for the KundO and ATO battery pendulum clocks.

You should be aware that the simple electronics in these clocks is likely more than 30 to 40 years aged and may have exhausted its life owing to natural causes.

Except for the suspension spring, maintenance parts for these clocks are no longer available. 'Doubt you'll locate a replacement glass dome.

The battery power is 1.5 volts. Some have been able to fit a flashlight (torch) dry cell in place of the rectangular dry cell package.
 

Tony10Clocks

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Thanks for the info Eckmill, but i think the electronics is missing, can't see anything that resembles an electronic circuit, is there any one that makes them or has a schematic drawing for them
Tony
 

ivancooke

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Tony, I have a clock the exact match of this, and any electronics are inside the coil.
If you fit a susp. spring and sort out connection to a 1.5 c cell battery, there's a good chance it will work.
If you want to see photos of the clock I have, let me know.
In fact if you hit this link, it should take you to a thread relating to my clock, and showing photos.

https://mb.nawcc.org/showthread.php?t=72932


Ivan.
 
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Tony10Clocks

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Thanks Ivan, I diid see your thread hope you got it fixed, i still have the original battery in it , and just checked the voltage and it was reading 1.48V
Cheers
Tony
 

Tinker Dwight

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Hi
There is a schematic on a pdf. It was posted as part of
a reply to:

"Kundo electro-mechanical clock help needed"

It shows a pnp germanium transistor. As was mentioned,
these do age and will eventually fail.
These can not be directly replaced with a silicon transistor
because the threshold voltage is higher on the silicon transistor.
Still, there are a couple options:

1. Add a small pulse transformer with a 1:1.5 to 1:2 ratio at the base
of the transistor.
2. Add turns to the sense coil to increase the voltage to the
transistors base. One would need to add about 50% more turns.

Number 2 above would require determining how many turns
are in the sense coil. This could be easily determined, experimentally
with an oscilloscope and a pulse generator. Still, there would
need to be enough space for the additional wire.
Number 1 could be done by mounting such a transformer on
the bottom or back of the unit. Such a transformer could be
a small audio transformer as the frequency is quite low.

In the schematic, I see something called a:
Dampfungswiderstand
It took me a little time to figure that it was a dampening
resistor. No value seems to be shown. I suspect it is not
critical and anything from about 500 to 5K might work fine.
In an earlier post, someone mentioned that there was
a capacitor in this design. There is no capacitor in this
schematic.
Tinker Dwight
 

Tony10Clocks

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Thanks Tinker, I'll have a look at it ( if i can find it ) see if i can make head or tail out of it. I'll let everyone know how i get on, Maybe in about 2 months time. I normally spend a fair while on a clock, as i only do it at weekends
Cheers
Tony
 

Tinker Dwight

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Hi
I know what you mean. As my signature suggest,
I'm a weekend tinker myself.
The pdf also shows various parts of the movement and
what look like part numbers.
Good luck
Tinker Dwight
 

Tony10Clocks

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Hello, I got my spring today, set it up but no go, Tried other batteries, still no go, put my multi tester on it and got a reading of 3k ohms, Is that good, Also when the battery is connected should there be a magnetic field, if so is it a strong field or a weakish one. Is the circuit in the coil itself or should it outside the coil.
Thanks in advance
Tony
 

Tinker Dwight

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Hi
With the ohm meter, you should see a high resistance
with the leads swapped in one direction and a lower
resistance in the other.
You should see no magnetic field with the battery connected
and the pendulum not moving.
To my knowledge, all the circuit is inside the case for the
coil.
The way it works is that in one direction of the pendulum swing,
the magnet on the pendulum induces a current in the tickler
coil.
This forward biases the transistor that causes current in
the drive coil.
The pendulum is then pulled a little faster.
As the other end of the magnet goes through the tickler coil, there is no
longer and induced current in the tickler. This causes the transistor
to turn off.
The drive coil bleeds its excess current through the resistor, keeping
the flyback voltage from damaging the transistor.
Things wait for another cycle of the pendulum.
Tinker Dwight
 

Tony10Clocks

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Thanks Tinker, That makes a bit more sense. I'll give it a check later today and let you know what i find.
Tony
 

Tony10Clocks

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Hello, I did some tests today. I connected the battery whilst the pendulum was in a still postion and there was a slight movement in the pendulum. So i swung the pendulum a little and on the up swing to the left i connected the battery, then on the return swing i disconnected the battery. And that seemed to keep the pendulum to keep swinging. But with the battery connected permanantly the pendulum comes to a stop.
Could it be a transistor or resistor Kaput
Tony
 

Tinker Dwight

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Hi Tony
It is most likely the transistor. Resistors typically fail
open or for the older carbon comp type, drift off
value by some percentage.
An open resistor could cause the transistor to fail
but as a minimum, the transistor is shorted, collector
to emitter.
Like I said before, I think one could get a silicon
transistor to work.
I'd be interested to see what is inside the coil case.
( Picture? )
Tinker Dwight
 

Mike Phelan

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I've not read all the posts in depth, but germanium transistors do sometimes tend to leak from C to E.

With the device disconnected and using a typical analogue meter with a 1.5v internal battery for the ohms range, and using the prods both ways round you will get something like:
B to E 1k
E to B more than 20k
C to E more than 10k
E to C more than 10K
C to B more than 20k
B to C 1k

None of these are critical.
They are still available - look for old scrap transistor radios with OC44, OC45, OC71's in them. Not AF11* as NASA foind to their cost when they used them in space probes.

However, think about the fine wire in the coils and the fact that the clock might have been lying around in a damp shed for years. It only veeds a few shorted turns from 10,000 or so to stop it working, and no resistance reading on a meter will tell you that. :eek:
 

Tony10Clocks

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Thanks for the info. I think i'll bite the bullet and delv into coil taking pics on the way and see what i find.............
Tony
 

Tony10Clocks

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Hello. I decided to look inside the coil today, It took about 20minutes to unwind it, and when fully unwound there was no circuit there. So i asume that the circuit was under the base originally. Anyway took some photo's as requested hope there helpful to anyone..
 

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eskmill

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For what it is worth. I have disassembled an otherwise "dead" KundO transistor switched battery clock solenoid. The photos below reveal the old-style semiconductor and its location in the bobbin of the solenoid. It is unclear when the manufacturer revised the design and eliminated the imbedded transistor switch.

Later designs used a simpler single coil with two leads terminated at a two transistor printed circuit usually located in the base of the clock.
 

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Tinker Dwight

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Hi
I guess next is a look inside that black box.
When req=winding the coil, make sure to get
the turns direction correct.
I see that the transisor one looks to have enough
space for additional turns to make the tickler
coil for a silicon transistor. It shouldn't be to
had to repair.
Tinker Dwight
 

Tinker Dwight

Registered User
Oct 11, 2010
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Hi
I guess next is a look inside that black box.
When req=winding the coil, make sure to get
the turns direction correct.
I see that the transisor one looks to have enough
space for additional turns to make the tickler
coil for a silicon transistor. It shouldn't be to
had to repair.
Tinker Dwight
Hi
I see that the black box is the battery. No place to
hide transistors there.
I wonder where the circuit is hiding??
Tinker Dwight
 

Tony10Clocks

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I think the circuit may have been a seperate part on the base, on the left of the battery where there is a mark where something had beeh stuck on.
Tony
 

Tinker Dwight

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Hi
I wonder if the other one, that was found in the box
that was just posted, has the same coil?
If so, there should be a module near it.
If yours is just the wires to the coil and nothing
else there, I'd think something could be made
to work.
Of course an original coil, with transistor, would
be easiest.
Tinker Dwight
 

Tony10Clocks

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Hello, Iv'e found 2 schematics one with 1 transistor and the other one with 2 transistors. If i just have the single coil would i need the one with 2 transistors or 1 transistor.
2 Tansistor
1 Transistor
Cheers
Tony
 
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Tinker Dwight

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Hi
Great find. The two transistor one it the one you want,
unless you want to wind the tickler winds.
If you can't find an easy source for the transistors,
a couple of easy to get transistors here in the US would
be:
NPN 2N3904 instead of BC168B
PNP 2N3906 instead of BC258B

The 2N3904 might be a little weak on gain but lowering
the value of the 39K a little should make up for it.
Places like JAMECO have these ( www.jameco.com ).
You still may need to play with some of the values to
set the pulse width for the best swing( note the changed
values in parenthesis ).
Dwight
 

Mike Phelan

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Dec 17, 2003
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TB
Germanium transistors are still available; if you are stuck I can post you one as you're in England. Or likewise if you go down the silicon route.
I can find the other passive components for you as well.

I think posting a single transistor costing 10p from USA would not be feasible!

Or find a scrap transistor radio pre-1970 from a car boot sale, but avoid any metal 4-lead transistors like AF117.
 
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Tinker Dwight

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Oct 11, 2010
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TB
Germanium transistors are still available; if you are stuck I can post you one as you're in England. Or likewise if you go down the silicon route.
I can find the other passive components for you as well.

I think posting a single transistor costing 10p from USA would not be feasible!

Or find a scrap transistor radio pre-1970 from a car boot sale, but avoid any metal 4-lead transistors like AF117.
Hi
The two BCxxx transistors shown in the schematic
he found are silicon and not germanium. I'd suspect
he might find these exact size but both of the ones
I mentioned could be bought for about $1USD.
The one transistor version would require a change in the
tickler coil to use a silicon one in place of a germanium.
Looking at the picture of the single transistor version,
the bobbin looks to have enough room for more turns
to be added.
It would seem to me that rather than replacing the
transistor with one that is known to fail in a short time,
replacing it with one that will last 100 or more years
is a better option( I don't think anyone knows yet how
long a silicon transistor can last but I suspect it is a long time ).
Tinker Dwight
 

Mike Phelan

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Hi Dwight

I hadn't spotted the fact that there were further posts and the OP is almost sorted now after finding a circuit diagram.
Hi
The two BCxxx transistors shown in the schematic
he found are silicon and not germanium.
Yes - all BC transistors are silicon, A* and O* germanium.
It would seem to me that rather than replacing the
transistor with one that is known to fail in a short time,
replacing it with one that will last 100 or more years
is a better option( I don't think anyone knows yet how
long a silicon transistor can last but I suspect it is a long time ).
Tinker Dwight
Generally, failure of germanium transistors is due to several things; the infamous tin whiskers in those with metal cans, as NASA found to their cost here, static damage due to lightning and such, and the fact that they don't like excessive heat.
Not sure about the short time, but I've quite a few radios from the 1960s using Ge devices, and an even earlier ATO clock with one. All these are glass encapsulated, though, not metal, and have never been replaced.
 

Tinker Dwight

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Hi Mike
I suspect that the two transistor circuit could be
used on a unit with the single transistor. One could
just remove the wires from the transistor and run
the two coil wires to the base where the two transistor
circuit sits.
As you said, the germanium transistors can be found
but are quite expensive. Removing one from an old
transistor radio is an option as well. I'd suspect the
output transistor would be the best.
Heat does the germaniums in quickly. The resistance
of the base to emitter goes up and reduces the gain.
I never looked into the root cause. It could be the
contact on the emitter bead.
Tinker Dwight
 
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