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How To Repair A Clock

Written By Thursday, June 16, 2022 Add Comment Edit

Eugene is a qualified command/instrumentation engineer Bsc (Eng) and has worked equally a programmer of electronics & software for SCADA systems.

Typical battery quartz electronic wall clock.

Typical bombardment quartz electronic wall clock.

Cleaning Battery Clocks

Once upon a time about of our clocks were wind-up devices, then we transitioned to electric clocks that plugged into a mains outlet. Present, many clocks are battery-powered by a single AA prison cell. The enemy of all clocks though is dust and grime that can easily seize up the cogs and stop the mechanism from working. In this guide, I show you which parts y'all can endeavour cleaning to get your clock working again.

Analog and Digital Clocks

The clock I'm fixing here has an analog brandish. However the electronics that drives the brandish is digital and uses an oscillator and counter scrap for frequency sectionalisation. To sympathise the somewhat confusing difference betwixt analog and digital which are words that tin can hateful dissimilar things depending on context, see my article "Analog vs Digital Signals and Displays — What'south the Difference".

How Does a Quartz Clock Work?

The mechanism (also called the movement) or working parts in a quartz battery clock is a bit simpler than in a traditional wind-up clock.

At the middle of the clock is a quartz oscillator, which generates a pulse every 2nd. An oscillator is a device that does something regularly, like a pendulum that swings dorsum and along, a tuning fork vibrating, a string on a guitar or the air in an organ pipe. All these are mechanical oscillators, only at that place are also electronic oscillators.

An electronic oscillator generates a voltage signal that repeats itself at a set frequency. In the instance of the oscillator in a clock, this runs at several m hertz or cycles per 2nd. An electronic component called a quartz crystal sets the frequency of the oscillator to well-nigh 32768 Hz with a high degree of accuracy. The frequency is divided downwardly and reduced so that information technology eventually becomes 1Hz or 1 cycle per second. The output of the oscillator drives an electromagnet that acts on a tiny magnetic rotor, flipping it one-half a turn every second. The rotor has gear teeth that mesh with a train of other gear wheels and this eventually turns the hands of the clock.

The proficient matter about electronic quartz oscillators is that their frequency is very stable and unlike mechanical clockwork, doesn't change much with temperature, humidity or other ambience weather condition. This means that bombardment clocks keep good fourth dimension and don't gain or lose minutes like a wind-up clock as the leap unwinds or temperature changes.

Why Practise Clocks Stop?

  • Loose or dirty battery connections
  • Low battery
  • Battery pips not long enough
  • Grime accumulating in the mechanism causing excessive friction

Commencement Steps: What to Try if a Clock Doesn't Work

  • Change the battery. It may simply be apartment. You can check battery condition with a universal battery tester like this ane suitable for 1.v volt AA, AAA, C and D cells and also pocket-size, square 9 volt "PP3" (MN1604) mode batteries
  • Clean the connections and battery terminals with rubbing booze (which is either isopropyl booze (IPA) or ethanol) on a cotton bud. The springy electrical strips can also become oxidised as tin the ends of the batteries. This oxidisation sometimes appears as a greyness or green coating. You lot tin can employ fine wire wool to remove information technology. If the battery has leaked and left a white deposit (potassium hydroxide from alkaline batteries), you lot can neutralise this first past rubbing with vinegar.
  • Check the bombardment terminals: Sometimes the terminal pips on batteries can be a little short. Endeavour slightly angle the positive terminal strip in the clock slightly. Caution! These tin can snap if you lot curve too much.
  • Check the hands: Make the sure the clock hands aren't rubbing against the clear cover over the face of the clock.
Universal battery checker suitable for AA, AAA, C, D and MN1604 (PP3) batteries.

Universal battery checker suitable for AA, AAA, C, D and MN1604 (PP3) batteries.

Battery connections can be cleaned with isopropyl alcohol (IPA), also called rubbing alcohol.

Battery connections can be cleaned with isopropyl alcohol (IPA), as well called rubbing booze.

Clean contacts with IPA.

Clean contacts with IPA.

Sometimes batteries can have short positive terminal pips.

Sometimes batteries can accept short positive terminal pips.

Try slightly bending the springy terminals if they don't make contact. Don't overbend.

Try slightly bending the springy terminals if they don't make contact. Don't overbend.

Next Steps: If the Clock Still Won't Run

If the clock yet won't run, the cogs inside may have crud on the teeth or axles. Even though there'south a cover on the mechanism compartment, in humid, dirty weather (e.chiliad., in a bathroom) grit and mildew can manage to make it. So you demand to do some cleaning. The solenoid in the clock only produces a tiny corporeality of torque or twisting forcefulness to turn the fiddling rotor. Any grime on the pins of this rotor can produce enough friction to stop it from turning.

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How to Clean the Clock Mechanism

  1. Remove the comprehend over the machinery. This differs from clock to clock. There may be lugs on the machinery compartment that appoint with the comprehend. If this is the example, push them gently aside with the blade of a screwdriver. Alternatively there may be pins that push into the cover similar in the photograph below. I was able to push into the hairline gap between the compartment and comprehend with a pocket-size screwdriver and prise upwardly the comprehend.
  2. Remove the rotor from between the jaws of the solenoid and the starting time couple of gears. These should but lift out without whatsoever difficulty. Friction affecting these gears is most likely to terminate a clock because further down the gear train, there'll be more torque to overcome information technology. Take a photo before disassembling so you tin put everything back together.
  3. I have found that article of furniture polish helps to make clean and lubricate the tips of the shafts of the nylon gears where they sit into the example and cover. Spray some polish on a tissue or cotton wool bud and dab it onto shaft ends and teeth and wipe off the excess.
  4. Remove any obvious dust or fluff in the movement.
  5. If you remove some of the gears, the hands of the clock may autumn off, and so you may demand to remove the clear faceplate to replace them.
To get at the mechanism, you need to remove the cover on the compartment that holds the gears and electronics.

To get at the machinery, you need to remove the cover on the compartment that holds the gears and electronics.

Inside the clock, an electromagnet moves the little blue magnetic rotor half a turn every second. This turns the other gears.

Inside the clock, an electromagnet moves the petty blue magnetic rotor half a turn every 2d. This turns the other gears.

This tiny rotor magnet is about 3/8" or 10mm long. Clean the two ends of shaft pins to reduce friction.

This tiny rotor magnet is near 3/8" or 10mm long. Make clean the ii ends of shaft pins to reduce friction.

You can clean and lubricate the tiny shafts of the gears with furniture polish.

You lot can clean and lubricate the tiny shafts of the gears with piece of furniture polish.

You can detach the lugs of the front cover of some clocks by pushing down with your fingers and pulling out at the same time.

You can detach the lugs of the front cover of some clocks by pushing downwards with your fingers and pulling out at the aforementioned fourth dimension.

.....alternatively push sideways on the lugs and then push down to remove the faceplate of the clock if you need to replace the mechanism or hands.

.....alternatively button sideways on the lugs so push down to remove the faceplate of the clock if y'all need to replace the mechanism or hands.

More Possible Fixes

  • Check the voltage on the electromagnet: This should change polarity every 2nd.
  • Reflow the solder: If y'all have a soldering iron, you can reflow the solder on the joints on the PCB. Sometimes a dry solder joint can forestall the excursion from working or make it stop working intermittently.
  • Cheque the metal strips: On some clocks, the excursion lath presses against strips of metal that supply power from the battery. These strips are springy and press on tinned pads on the PCB. In a bath, steam can cause corrosion at these points of contact. Remove the PCB and make clean the pads and bound contacts with IPA and fine wire wool.
  • Bank check the magnetic rotor axle: The beam of the magnetic rotor can tarnish if information technology's made of brass, making it rough and increasing friction, causing information technology to stick. More expensive clocks and watches have jewelled bearings (e.yard., rubies) in which the tiny axles of the cogs rotate, however inexpensive quartz clock movements just accept a nylon plate into which all the axles of the cogs fit. Yous can try adding a tiny driblet of oil, (less than the size of the head of a pin) using the tip of a pin or a pointed awl to the indicate where the rotor axle fits into this plate.
Reflow solder on the joints.

Reflow solder on the joints.

Use the tip of an awl or pin to apply a tiny drop of oil to the bearing.

Utilize the tip of an awl or pin to apply a tiny drop of oil to the bearing.

If the Clock Still Won't Start, Supersede the Mechanism

It turned out that the electronics of my clock in the photos above was faulty. You tin buy a replacement move like this one on Amazon. This production has bones plain hands.
Mechanisms are somewhat not-standard, and so you'll need to check that the hands are the correct size and will suit the style of your clock. Alternatively, if they are patently rectangular types, you demand to check that they can exist cutting and shortened. The threaded slice that fits into the hole in the face of the clock sometimes differ in diameter and length. This should be long enough that any rubber washers to terminate the mechanism turning and bracket hooks for fixing to a wall can exist replaced with the piece projecting sufficiently to fix it in place with the retaining ring. Diameter isn't every bit critical, merely it should exist small plenty so it fits through the hole. If information technology's too small-scale, it'southward a piddling more tricky to keep the mechanism centered properly.

You can buy replacement mechanisms for a few dollars.

Y'all can buy replacement mechanisms for a few dollars.

how-to-fix-a-quartz-digital-clock-that-wont-work
Attach the retaining ring for the clock movement. Don't excessively tighten it as it can deform the insides of the movement.

Adhere the retaining ring for the clock motility. Don't excessively tighten information technology as it can deform the insides of the movement.

You may need to shorten hands. You can probably use a sharp scissors.

You may demand to shorten hands. You can probably use a sharp scissors.

Replace both the hour, minute and second hand (if supplied) and point them all to 12 o'clock. Then set the time after replacing the battery.

Replace both the 60 minutes, minute and second paw (if supplied) and betoken them all to 12 o'clock. Then prepare the time afterward replacing the bombardment.

Using Apartment AA Batteries

When a gadget indicates that the batteries are apartment, this is oftentimes because electronics or software detects that the voltage is below a threshold level sufficient to run the device. This happens with high-ability devices that need a minimum voltage to operate. Notwithstanding the free energy remaining is often acceptable to run bombardment clocks for up to half dozen months.

References

Wikipedia: Quartz Clock

This content is authentic and truthful to the best of the author'southward cognition and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2022 Eugene Brennan

Source: https://dengarden.com/misc/How-to-Fix-a-Quartz-Digital-Clock-That-Wont-Work

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