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  1. #1

    Default Repairing a school's Simplex Clocks (Frequency Synced)

    Hello, I'm new to this forum.

    I'm a high school student and I've made it my project to repair the Simplex electric clocks at my school. They are actually rectangular and located inside a wall panel with a speaker, thermostat and phone, which I have yet to see anywhere else. They use frequency synchronization, running at 4,680hz.

    The school was built in 1976 and the original frequency generator is still in use and we have a slightly newer 2350 master clock. I'm happy to say that many of them continue to work as designed, but many have failed in a few different ways and I was wondering if someone could give me some help....

    Many of the clocks no longer synchronize. They will do the hourly and 12 hour correction if I manually close the solenoid. The ones that don't sync up still have the vacuum tubes inside. What's the best way to fix this issue? I've purchased a circuit board replacement from American Time and Signal which was successful, but for $50 each, it's out of our price range.

    The remainder of the broken clocks don't move at all. I have gotten some to start back up by spraying WD-40 into the movements and either just unplugging them and plugging them back in and/or giving one of the gears (located in the circle above the motor) a gentle push. The ones that won't exhibit a weird problem: they'll work for a while but then they will somehow jam(?). The second hand will literally be impossible to move forward with the motor or with your hand. If i turn the second hand backwards and let it go, it will work but then stop at the same place again. What causes this?

    Thanks for your help.

    I attached a picture of the wall panel and a picture of the inside of one of the regular glass clocks we have (identical mechanism). (I am aware that in the photo there is a torn wire...I found out the hard way).
    Attached Thumbnails Attached Thumbnails IMG_0918.jpg   IMG_0919.jpg   IMG_0924-1.jpg  

  2. #2
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    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: alanwh)

    Hi
    Firstly, WD40 is not a good long term solution.
    Proper clock oil is needed. The problem now is that
    the WD40 will need to be cleaned out first.
    I'm curious about the tubes. I'd think these are
    to detect the sync tone and operate the solenoid.
    You'll need to find an old tube tester someplace.
    I can't make out the numbers but many of these
    old tubes can still be found.
    Most likely, many of the motors have failed. Replacing
    them is one option. Rebuilding them is another.
    It all depends on the amount of damage.
    I'd be curious to see a schematic of the circuit for the
    clocks.
    Where in the world are you located?
    Tinker Dwight

  3. #3
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    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: Tinker Dwight)

    Hi, kwhite, welcome to the message board. You have a monumental task with this clock system. It sounds like the transmitters are not putting out enough signal to activate the correction. The newer receivers will work with less signal than the older ones. Fixing this may be as simple as replacing the tubes in the transmitters (many of these systems had more than one transmitter). The tubes in the clocks just about never fail.
    It also sounds like many of the wall clock movements have failed due to wear. Spraying with WD40 won't compensate for wear, and will only be a temporary solution, as it will harden and make things worse.
    You can buy new movements much cheaper than new clocks (ATS).
    harold bain, Member ch 33
    "If it won't "tick",
    let me "tock" to it"

  4. #4

    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: Tinker Dwight)

    The tube is part of a 4 component receiver in each of the clocks. Normally they would use a third red wire for the signal to close the , but these pick up a signal/pulse over the buildings wiring (so they can be plugged in anywhere w/o any special wiring.)

    They use a type 5823 thyratron tube as an electrical switch to close the solenoid. I did find replacement tubes but they didn't fix the problem. I think it's because some don't close "enough" to put the correction arm in enough to move up.

    I used the wd40 to clean out the dust, concrete and metal shavings that built up in the movements over the years which seemed to work perfectly (it's been weeks and they still turn).

    I'd be really surprised if the motors have burnt out as the synchron motors they use are designed not to fail even if they are jammed, are still warm to the the touch. I'm almost positive there's something wrong in the movements.

    Thanks for your help. I'm located in Massachusettes.
    -> posts merged by system <-
    What should I use instead of wd40? I agree that the tubes don't burn out as they still illuminate but I'd be surprised if the signal is too weak as I can actually hear the signal generator (the generator is located in a central location in a relatively small building.

  5. #5

    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: alanwh)

    Where in Massachusetts? I DON'T ADVISE A HIGH SCHOOL STUDENT TO GO NEAR A TRANSMITTER OR GENERATOR THESE UNITS ARE CONNECTED TO HIGH VOLTAGE AND THE CAPICITORS WILL HOLD A CHARGE THAT WILL MELT A SCREWDRIVER IF IT TOUCHES THE WIRES WITH THE POWER SHUT OFF.

  6. #6

    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: caperace)

    I was not planning on touching the generator myself (it is in fact connected to the main 480v line. That's what the building electricians are for.

  7. #7
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    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: alanwh)

    To properly clean the movements, they need to be removed from the clock, and cleaned out with paint thinner or something similar. If you are going to spray it with anything, get some Slick 50 "One Lube", which will be much less damaging than WD40.
    What usually wears out is the correction ratchet. Where it's arbor goes through the movement plate will have an elongated hole. This will eventually jam the movement and likely chew some teeth off the intermediate gear that is connected to the back plate. These motors do fail (nothing lasts forever).
    Since you have a motor generator instead of a transmitter, the correction signal is probably as good as it ever was.
    I hope you are getting some supervision from a shop teacher, or someone who knows his way around electricity.
    harold bain, Member ch 33
    "If it won't "tick",
    let me "tock" to it"

  8. #8

    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: caperace)

    Quote Originally Posted by caperace View Post
    Where in Massachusetts? I DON'T ADVISE A HIGH SCHOOL STUDENT TO GO NEAR A TRANSMITTER OR GENERATOR THESE UNITS ARE CONNECTED TO HIGH VOLTAGE AND THE CAPICITORS WILL HOLD A CHARGE THAT WILL MELT A SCREWDRIVER IF IT TOUCHES THE WIRES WITH THE POWER SHUT OFF.
    I live in Mass, where are you, my e mail is lanejim@verizon.net, I may be able to help you.

    Jim

  9. #9

    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: caperace)

    Just in case anyone was wondering (many expressed concerns over me doing this)... I did not start doing this clock project blindly. I do in fact have knowledge about electricity and electrical safety and someone gave me detailed instructions about testing them before I started (though the wd-40 was my idea; apparently very incorrect). The school calls me "Mr. Fix It" as I do similar repairs with the lighting system in the theatre, the computers and the phone system. Unfortunately, there's no shop teacher or electricians that have to time to do "low priority" stuff like the clocks and the school is basically out of money. That's why I posted here, as I'm stuck past being able to replace the receivers or attempting to grease/free the movementS.

    Does it make any sense for the solenoids in the clocks not being strong enough to move the arm far enough? The solenoid closes when its supposed to, but it won''t actually do anything in terms of moving the correction arm up with the gears unless I'm the one closing it or pushing up slightly more with a pen.

    Thanks for everyones help!

  10. #10
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    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: alanwh)

    The solenoid probably needs to be adjusted so there is a very small gap at the bottom when it pulls in. Also the segment that rides up the ratchet gear may be worn, so it won't ride up to unlock the correction.
    Unfortunately many school boards are caught in a situation where there is no money for frivolous things like clocks.
    harold bain, Member ch 33
    "If it won't "tick",
    let me "tock" to it"

  11. #11

    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: harold bain)

    Bravo! This is a wonderful project and I'm glad you are undertaking it in a safe way.

    As noted, we have members in Massachusetts who should be willing to help.

    I know little of these particular clocks but believe there are both tube and solid state receivers. Also I think these clocks often come up as surplus on eBay and the like, often for low prices. I will look and see if I have any clocks or parts around. One question someone could answer is, are the Simplex wire-controlled clocks, or some of them, the same as these except for the receivers, so that you could substitute ones with good movements.

    Also - if you did not already mention it, tell us all about the system. How many of these slave clocks are in the system,and are they all corrected this way or are some wired? What are the two master clocks doing?

  12. #12
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    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: skruft)

    Skruft, the only difference between the wired sync clocks and these electronic clocks is the soleniod, and the receiver. The movements are identical. I didn't notice any mention of two master clocks.
    harold bain, Member ch 33
    "If it won't "tick",
    let me "tock" to it"

  13. #13

    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: harold bain)

    We have one 2350 Master Clock (not original, digital, circa 1980s), that controls the clocks (and the bells that go through the PA system).

    Harold bain is correct in that our clocks are identical to any other simplex clock (even though they are rectangular and made of steel to go inside a panel, they are identical to the regular glass circular ones that we also have), the only difference being that they have a tube or PC board receiver in them.

    Bit more of an explanation on how the system works: Most Simplex/IBM clocks would use a 3rd red wire thats connected to the master clock to trigger the solenoid to run the correction cycle. At my school there is instead a special signal generator located in the electrical room between the main power lines from the outside and the building transformer and distribution panels that provide power to the whole building. The generator injects a 4680hz pulse into the regular 60hz 120 volt electrical wires in the building when triggered to do so by the master clock, which the clocks receive and closer the solenoid. The benefit of this system is that you can plug any of these simplex clocks into any outlet in the building and they will work and set themselves.

    The school has ~ 60 slave clocks (~55 of them being located in the panels, ~5 of the regular circular, glass ones that you usually see). ~20 of them work correctly, another 20 work but donít sync, and the remainder donít work at all.

    Simplex no longer makes these frequency synchronized clocks and recommended that the school switch to their newer model clocks in the late 90s, but that would have required a total overhaul of the wiring in each of the classrooms and all new clocks, something that was way out of budget.

    American Time & Signal still makes the receivers (in circuit board form) and even the signal generators (now silicon/solid state).

  14. #14
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    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: alanwh)

    Seems strange that the master clock supplied in 1976 needed replacing in the 1980's. It was probably a model 943. These were pretty trouble free, except for the bell programmer, which would have been a tough fix for any but an experienced repairman.
    At 35 years old, the slave clocks are reaching the end of their useful life, considering no one ever does any preventive maintenance on these. They would last a lot longer with occasional lubrication (keep in mind that WD40 is not a lubricant, it's a water dispersant).
    harold bain, Member ch 33
    "If it won't "tick",
    let me "tock" to it"

  15. #15

    Default Re: Repairing a school's Simplex Clocks (Frequency Synced) (By: harold bain)

    Harold bain your response reminded me: all of the clocks were serviced in both 1988 and 1995 by simplex. Most, if not all, do not have movements from 1976.

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