quartz watch repair

Quartz watch repair

I started with the repair of old analog mechanical watches and I really like them however analog mechanical watches are always less accurate than quartz watches because the frequency with which a mechanical balance oscillates depends to some degree on the amplitude and the position. All kinds of efforts have been made to compensate an analog mechanical movement for those effects but it does never really work. Quartz oscillators have no position dependency and their temperature drift is as well rather small. The only problem with Quartz watches is that they need a battery and one has to replace that battery once in a while.

Quartz watches are generally much easier to fix than analog mechanical watches. The main reason is that they behave "digital". They do either run and keep time or they have a problem. The "working but not keeping time at all" state that mechanical watches can end up in does not exist here.

A lot of watch makers just replace the entire movement when it is not working anymore. This might not be possible for old watches and there they just fit a new and different movement into an old watch. I think that this is really the wrong strategy. Quartz movements can be repaired in many cases. In those case where you need spare parts you can often use parts from a similar movement from the same manufacturer and just swap the defect part.

How to repair a quartz movement?

Good swiss quartz movements can be repaired. Cheap chinese or japanese movements can only be replaced as a whole.

Quartz watches have in general 5 areas where they can fail:

Mechanical problems due to "dirt" in the movement. This is by far the most common cause for a defect quartz movement. Just clean the movement as described below. Broken or worn out cog wheels are rather rare.
Salts and oxidation around the battery compartment. Just take the involved parts apart and clean them. Corroded metal contacts can be polished with a bit of polishing paste. Those tiny parts are best polished with a small piece of leather (2mm x 3mm). Grab the leather with watchmaker tweezers, dip it in metal polishing paste and then rub it gently along the little contact pin or whatever you need to polish.
A defect coil. The coil that powers the step motor is made of a wire thiner than a human hair. It is easily damaged by somebody who does not know how to change a battery. A screw driver or just finger nails hitting accidently the coil can break the wire. It's almost impossible to repair. It's better to replace it.
A defect tuning fork quartz crystal. This is a very rare defect but extrem temperature changes or mechanical shock can break it. You can replace them. Those are 32.768KHz tuning quartz crystals and they cost only a few cents. The watch might be off by a few minutes per month after replacing the quartz. Some older watches can be adjusted but that is a bit of trial and error without the right equipment.
Defect electronics. It's mostly impossible to repair them unless it is due to a corroded wire track on the circuit board. Replace the whole circuit board.

Quartz watch quick diagnosis: Mechanical problem or electrical problem?

A quartz watch may not be ticking because of a mechanical problem (the motor is mechanically stuck) or because of an electrical problem. It is easy to check the electrical signal that the motor is receiving. For this you will need an old fashioned analog multimeter and you set it to the lowest possible DC voltage setting (e.g 2.5V DC). Check with the probes the voltage on the coil contacts. Be sure to not damage the fine coil wire soldered to those contacts. You should see the needle in the analog multimeter twitching every second. The voltage should alternate and you should see the needle move just slightly below zero and then slightly above zero. Those are very short pulses that the electronics in a quartz watch sends to the coil. A digital voltmeter will not register those.

Analog multimeter to diagnose the electronics in a quartz watch.

Cleaning the a watch movement

Watches accumulate over time dust and small metal debris inside the movement. All watches have a friction fit to allow you to change the time while the movement is running. If there is oil on that friction fit then the movement will not be able to drive the watch hands any more properly. The friction fit will slip and the time will be off. A quartz watch that is off by several minutes per week has usually mechanical problems, not eclectic problems.

Quartz movements are more simple in their mechanical design. They have very few cog wheels and it's easy to get to them. This open design does often allow you to wash the movement in lighter fluid without taking it apart.

Lighter fluid to clean watch movments.

To clean a quartz watch you just take the movement out of the case, dip it in a small bowl with lighter fluid and move it a bit left and right to allow for the flow of lighter fluid through the movement. This will wash old oil, debris and dust out of the movement and you will find small particles at the bottom of the bowl.

I have installed a new battery just a few month ago and now the watch needs again a new one

If you are sure that the battery is was of good quality then this is probably a sign of oil in the movement getting old and sticky. The friction in the movement has increased.

An easy way to fix this is to first apply a bit of very thin Moebius quartz oil. After that you wait a few days (watch running) until the oil got into all the pivot holes where it dissolved the old and sticky oil. Finally you wash the excess oil away with lighter fluid. Just wash the entire movement in lighter fluid. Traces of oil will remain in the movement and that is enough. You don't need to take the movement apart for this procedure.

Replacing watch crystals

This is not specific to quartz watches but I don't have a generic "watch" page therefore I am putting it here.

Old pocket watches have often damaged or scratched crystals and replacing cracked or chipped crystals or polishing scratched ones can make a big diffrence. The watch looks much better when the crystal is clear and free of cracks.

Plastic crystals need only to be replaced if they have a crack. Scratches can polished out with a bit of 1μm diamond polishing paste (or any univeral metal polishing paste). Just put a tiny amount on a dry cloth and ploish the crystal by hand using circular movements. Most scratches will be gone in about 3 minutes. Do not use motorized ploishing wheels. They do often rotate too fast and get very hot. Heat will damage the plastic.

Plastic or glass watch crystal?

A chipped or cracked crystal needs to be replaced. I would always try to find out what the original crystal looked like. Just because the watch is old does not mean it has to be a glass crystal. Molnija watches from the 1940's had already "un-breakable" plastic crystals. With old watches you are often not the first owner and previous owners may have replaced the crystal already. To just copy the style of the previous one might not be correct either. Look at photos and descriptions of similar models. Real railroad watches had glass crystals.

Replacing a plastic crystal

There are special crystal replacement tools but you don't need them. Just remove the movement from the watch and then try to press the plastic crystal into the corresponding groove on the bezel. It should just pop-in. There is no glue neede. The plastic crystal is held in place with a compression fitting. Sometimes you will have to bend the crystal a bit with your fingers (center of the dome up, outer perimiter down).

Replacing a glass crystal

Most pocket watches did originally not have any glued crystals and if you have the right size then you will not need any glue either. If possible measure the size of the old crystal with calipers and then buy a few crystals around that size. Look for somebody who is selling them in 0.1mm steps. Old crystals might not have been measured in millimeters and conversion tables are available. The procedure to deterimine the right size is as follows. Find the crystal size that you can still press-in with your hands and then take next bigger one. Example: 38.0mm can be pressed into the metal ring holding the crystal (bezel) with a slight poping sound. That means you use the 38.1mm crystal. Place the metal bezel onto a 40W light bulb for 15min. This will heat the bezel. Please the crystal that was just too big into the fridge. Don't put it into the freezer. Too big temperature differences cause chips on the crystal when you bring bezel and crystal together. The heat of the light bulb causes the bezel to expand and the crystal will shrink a bit in the fridge. Put a cloth onto your table (thermal insulation), get the crystal and the bezel and you will notice that the crystal fits easily. Wait a few minutes until everything comes back to room temperature. The crystal is now held thight, no glue needed.

Some people just glue-in a smaller crystal but that is not "authentic" for most pocket watches. The correct method of fitting a sligthly too big crystal is more expensive and requires ususally that you buy a few (e.g 37.9mm, 38mm, 38.1mm, 38.2mm) and then test to see which one is the right one. If you absolutely need to glue the crystal then stay away from superglue. Superglue can produce some fumes which cause white deposits. Use a glue called "G-S Hypo Cement".

ESA 944.111 movement

This is a movement made by the swiss movement manufacturer ETA. It has 7 jewels but unfortunately as well a lot of plastic. I had a beautiful watch with a movement that had an electrical defect and I found an old and ugly but working watch on ebay with the same movement.

The task was therefore to swap the movements between the two watches. To do this one has to take out the dial.

The pitfall with this movement is that it has no cannon pinion (like most quartz movements). The dial is not mounted with posts that are clamped by screws. The posts are just kept in place by friction.

This makes it very likely that you pull a bit on the gear-wheel that holds the minutes hand when you take out the dial.

My problem was: how to get it back in?

The movement has a razor blade thin gear-wheel that snaps onto the bottom of the wheel holding the minutes hand. Two tiny metal bridges going across that gear snap into grooves on the axis of the gear-wheel holding the minutes hand.

Friction fitting on a 644.111 quartz movement

The friction fitting allows you to set the watch hands. This bit of friction allows you to manually turn the minutes hand while it is otherwise attached to the "gear-box" and the motor.

The problem is you can't just press the cog wheel for the minutes hand back in. The razor blade thin cog wheel will not snap onto it.

The way to fix it is to take it all out and place the razor blade thin cog wheel onto a piece of leather. It should be a firm leather patch. Take now the cog wheel for the minutes hand and press it between the bridges that go across that razor blade thin wheel. The leather is a bit elastic and it will push it onto the cog wheel for the minutes hand.

Now put everything back in.

The dial side of a 644.111 movement. You see the cog wheel for the minutes hand in the middle.

Charles Hubert stainless steel quartz pocket watch

I bought recently (Oct 2013) from pocketwatchsite.com one of those Charles Hubert open face stainless steel quartz pocket watches. It was dead on arrival. I contacted therefore the seller to see how this can be resolved. He offered me an RMA but it turns out that as per his policy I would need to assume the cost of the return postage and any transaction fees. Plus it turns out that this was his last watch. In other words I would have had at the end of all this just trouble and fees but no working watch. So be very careful with www.pocketwatchsite.com. I told him that I would not agree to his RMA and then he decided that the item was damaged in transit and the shipping company should assume the cost.

In any case I had the feeling that it is likely a minor problem and decided to open the watch and investigate myself what was wrong with it. I was suspecting an empty or loose battery.

The battery was however not the problem. Some metal dust had made it into the movement. It says on the movement "swiss parts, china assembling".

At first I was not sure where that metal dust was coming from but then I took a lint free tissue, put a drop of fine oil on it and went along the inside of the case. The paper came back completely gray, almost black!

It looks like the cases are not properly cleaned after production and there are small metal particles everywhere inside the watch. It's really Charles Hubert's fault. They should have recalled all those watches.

I spent a couple of hours cleaning the whole watch and the movement. After that the watch was running again.

It's actually not a bad watch. Sloppy assembly but the materials and the design is very good. It has rubber seals on the stem and on the back cover. I would not trust it to be really water tight but it's still very good to have and it protects the watch against dust and lint from your pocket. The crystal is a mineral glass not just plastic and the movement is good too.

The movement is a swiss Ronda 513 movement with one jewel. The expected battery life of the v371 battery is 45month. (Ronda 513 datasheet, 1.8Mb, from http://www.ronda.ch).

The only "design flaw" that I noticed was related to the seconds hand. If you just take a quick glance at the watch then you will easily read the wrong time because the seconds hand is black just as the other hands and they are all the same width. I solved that problem by painting the seconds hand white.

It's a good watch but you need some watchmaker skills to get it to work.