DIY coffee grinder repair

In detail: do-it-yourself coffee grinder repair from a real master for the site my.housecope.com.

Not so long ago, coffee beans were ground mainly with hand mills, and only with the advent of coffee grinders with electric motors, this process was mechanized. Electric coffee grinders are of shock and millstone action. Table 1 shows the main parameters of different types of electric coffee grinders.

In the electric coffee grinder ECMU-50 of impact action, coffee beans are broken by a two-blade knife rotating at high speed (Fig. 1). An electric motor with a noise suppression device is installed in the plastic casing of the coffee grinder. The engine is mounted on rubber shock absorbers to reduce engine noise when grinding coffee beans. The grinder is equipped with a locking device that shuts off the engine when the lid is opened. During the operation of the device, the motor may turn off due to weakening of the contacts in the blocking device or the switch button.

Electric coffee grinder device ECMU-50

Dismantling the coffee grinder begins by unscrewing the anchor of the two-blade knife motor. For this purpose, a screwdriver is inserted into the hole in the bottom of the housing, where there is a slot on the lower end of the engine armature. Holding the shaft with a screwdriver, turn the two-blade knife in the direction of its rotation during the operation of the coffee grinder and unscrew it. There is a hexagonal plastic gland head under the knife in the bean cup, which protects the grinder from ground coffee getting into it. Take a socket wrench of the required size and unscrew the head counterclockwise. Remove the press-veneer gasket under the bowl and gain access to the engine mount. Press on the bracket, which presses the engine through rubber shock absorbers towards the bottom of the coffee grinder housing, and by slightly turning this bracket to either side, the engine is released. The motor is removed from the housing together with the locking device.
In the event of a malfunction of the collector motor (for example, strong sparking of the brushes), then in detail diagnostics and troubleshooting are described in the article repairing a vacuum cleaner.

Video (click to play).

The collector motors of the electric coffee grinder and the vacuum cleaner differ only in power, respectively, and in size. All structural units are the same.
The assembly of the coffee grinder is carried out in the reverse order.

Electric coffee grinder EKMZH-125

The EKMZh-125 electric coffee grinder belongs to the burr-action devices (Fig. 2). Coffee beans are ground between two millstones: mobile and non-mobile. The movable millstone is driven by an electric motor. The coffee grinder is switched on by pressing the button and the switch. The grinding degree of the beans is adjusted by turning the knob located under the grinder housing.

Rice. 2 General view of the EKMZh-125 electric coffee grinder

Cord storage device;
Lid;
Immobile millstone;
Grain bunker;
Movable millstone;
Bunker for ground coffee;
Electric motor;
Regulator;
Interference suppression device

Rice. 3 Schematic diagram of the EKMZh-125 electric coffee grinder
C1 - capacitor 0.25 μF;
C2 - capacitor 0.01 μF;
C3 - capacitor 0.01 μF;
M - electric motor DK 65-60-10;
L1, L2 - chokes;
S1 - blocking device;
S2 - microswitch;

Buying already ground solid products (coffee, nuts, cereals) is quick and convenient, but no one can guarantee that the product is 100% natural. To be sure of the quality of the ground products, you can buy a coffee grinder and grind coffee beans, spices, etc. with your own hands.

The most ridiculous and unpleasant situations can be a reason for disassembling a coffee grinder.

On multiple thematic forums, consumers indicate such problems with the device:

Broken part (for example, a switch, a loose cord, reduced speed and a complete stop of the electric motor).
The knife is dull and needs to be replaced.
Contact of the grinded product with electrical components.
Curiosity, a desire to know what parts a coffee grinder consists of.

Each device model is disassembled differently. In order not to break the grinder, you need to follow the instructions from the manufacturer or the advice on the seller's website.

German Bosch technology is known for high quality products, durability and versatility of devices. In the assortment of coffee grinders, manufacturers often choose two photo models - Bosch mkm-6003 and Bosch MKM-6000. Both partings are characterized by high power, but the disassembly of each model is different.

To disassemble the Bosch mkm-6003 coffee grinder, you must first remove the impeller - in a clockwise direction. Then loosen the wire and pull the motor towards you. If there is debris on it, you can clean it off with a soft brush. It is better not to touch the motor of the Bosch mkm-6003 coffee grinder itself, and in case of a malfunction, contact the master. The detailed performance of each disassembly operation can be viewed on the video on the Internet.

Bosch coffee grinder

Disassembling the second model is much more difficult, you cannot do it with your hands alone. The best assistant for opening the Bosch MKM-6000 coffee grinder will be two flat-slot screwdrivers (no more than 1.5 mm thick, the distance from the slot is 8 mm, the width is 4-6 mm).

Dismantling the Bosch Coffee Grinder

Work process (designed for two people):

Take the grinder with one pair of hands, set it horizontally and hold it firmly.
With the second pair of hands, take a screwdriver and, at a distance of about 8 mm from the hole for the electric cable, drive it into the gap between the lateral cylindrical part and the bottom to a depth of 8 mm.
The first screwdriver must be inserted at an acute angle, heading up from the bottom of the device, with the second screwdriver, help the first to make a gap.
Floor increase in the pressure angle of a screwdriver inserted into the gap; the coffee grinder has been opened.

Before you disassemble the Bosch coffee grinder, you should get a camera to create a photo of step-by-step work. This will help to quickly and correctly assemble the device.

Soviet manufacturers of household appliances for the kitchen tried to make it as functional and convenient as possible. Even after many years of operation, the ZMM coffee grinder performs its functions perfectly, but if problems arise, the device can be disassembled. This must be done in the following sequence:

Remove the knife with a screwdriver - insert it into the slot on the bottom of the device and unscrew the part with a smooth counterclockwise motion.
Unscrew the plastic nut by turning the pliers counterclockwise 90 degrees.
Remove the plastic glass and cup holder.
With a gentle movement, the metal washer is removed from the axis holding it.
By simultaneously pressing the fixing plate and the blocker, turn the parts also counterclockwise and remove the plate (after it comes out of the grooves).
Next, you need to remove the power button after the fixing spring is bent.
Remove the dirt protection washer from the axle.
- Release the wire after carrying out such manipulations: bend the ring in the lower part of the ZMM coffee grinder, unscrew the two screws securing the electric wire.
Remove the appliance motor.

Read also: DIY Mitsubishi Sigma repair

Saeco Grinder Detail Example

To repair the engine or determine its performance, a multimeter and knowledge of where to measure the resistance of the windings are needed. Therefore, we will only touch on the relative minor problemsthat can be eliminated even with minimal tool handling skills.

A broken power cable is visible to the naked eye. But if the bend is close to the case, you can detect a breakdown by simply moving the wire. If the device begins to show signs of life, it means that you will have to change the cable.

Lock failure occurs due to clogged pressure mechanism (is in line with the cover groove) or the inner plate is not pressed. Checking the blockage is simple - press on the protruding plastic element with a thin screwdriver. If, at a certain position, the coffee grinder comes to life, you need to disassemble it and remove the dirt.

There may be several reasons: from a cable break inside (to eliminate such a problem, you will need skills in working with a soldering iron) to engine failure. In this case, verification will require special knowledge. In this case, repairs are economically ineffective, rewinding or buying a new engine is required, it is often easier and cheaper to buy a new grinder.

One of the reasons is partial failure of the motor, burnout of one of the windings. Repairs can be a problem. Diagnostics, rewinding or expensive replacement will be required.

The most common cause is contamination and oxidation of bearings or sleeve bushings. This problem is very often observed in the Bosch 6000 series coffee grinders. To eliminate contamination, you need to carefully disassemble the device, check the ease of sliding of all blocks, lubricate the bearings. The Bosch 6000 models do the following:

the sliding sleeve is removed from the shaft (upper part);
the shaft is treated with alcohol;
if there are obvious signs of corrosion, it is removed using special tools or WD 40.

The shaft can be machined sandpaper-zero, you need to act carefully. The procedure shown in the following video is not a commonly used one. With diligence and constant repetition of this kind of maintenance, it is possible to change the gap in the sliding sleeve, resulting in all kinds of problems.

The coffee grinder can be repaired periodically. Maintenance procedures include lubrication and decontamination. To avoid accidents, do not operate the grinder in modes not recommended by the manufacturer. For example, grind sugar into powder, grind herbal spices, process large masses of grinding. Each technique has its own operating rules and if you do not violate them, the device will work for a long time and trouble-free.Modern household appliances are not durable. And if you still use the device not for its intended purpose, then the rate of its failure increases significantly. This can happen with a coffee grinder if sugar and other harder foods are ground instead of coffee beans. But, regardless of whether the device broke down due to improper operation or for other objective reasons, you should not rush to contact the service center. Most likely, it is quite possible to repair the coffee grinder with your own hands.Today's electric coffee grinders are available in two types: millstones and percussion grinders. The lion's share space in the case the device is occupied by an electric motor - up to 80%. The rest of the area is dedicated to coffee beans. For instance, at millstones the grinder is divided into three sections. The first is filled with a portion of raw materials for processing. In the second, grinding takes place directly. And in the third, finished products are assembled. Image - DIY coffee grinder repair

V impact type designs installed knives. It is they who grind the grains into powder at a high rotation speed. Sometimes this mechanism is called rotary. And it only has one hopper that holds roasted coffee beans. Processing takes place in it. And the ground raw materials are simply poured into another container. In terms of its structure, such a coffee grinder is very similar to a blender.

Important! All devices are equipped with a motor lock when the lid is open and overheating protection. In many models, an additional pulse mode has been added, which with short engine stops helps when crushing harder products. For example, when you need to make powder from sugar.

Rotary coffee grinders often set a timer... It is needed to regulate the degree of grinding. The longer the process, the smaller the product yield. In millstone structures, this role is played by grinding depth adjuster... To do this, increase or decrease the gap between the millstones. Unequal grinding fractions are needed to prepare a drink according to different recipes.

Advice! To brew coffee in cezve, you need to grind the beans into dust. And for brewing espresso, a coarser grind is needed.

It is not difficult to disassemble the device if you know the diagram of the device. The design of all grinders is almost the same, but the assembly is different for different brands. And the famous Bosch company has two models with different disassembly methods.

It is easy to find people who still successfully use Soviet household appliances. Produced in a long-defunct country, coffee grinders are not inferior in productivity to their modern counterparts. They will open a list of instructions for the correct disassembly of such devices.

Made conscientiously back in Soviet times ZMM brand coffee grinder you have to disassemble, if not for repair, then at least for cleaning and maintenance work. The sequence of actions is as follows.

Free the knife. To do this, find a slot on the bottom of the case, insert a screwdriver into it and unscrew it counterclockwise.
Using a spanner wrench or pliers, unscrew the plastic nut by half a turn (left or right), which is located immediately under the knife.
Remove the plastic cup holder with the glass.
Remove the metal washer from the retaining axle.
To remove the plate, you must simultaneously press on it together with the blocker and turn it counterclockwise until it comes out of the grooves.
Bend back the retaining spring and release the switch.
Remove the dirt protection washer from the axle.
Move the ring at the bottom of the housing and unscrew the screws securing the electrical cable.
Take out the engine.

Important! When removing the knife, there is a risk of ripping off the slot. After this, further disassembly will be impossible. To prevent this from happening, you must first spray on it from a can of WD-40 and wait a few seconds. This will make it much easier to unscrew.

Completely similar sequence diagram when disassembling another Soviet model - ECMU 50. But modern electric coffee grinder "MIKMA»ECMU IP-30 from a Moscow manufacturer (a subsidiary version of the Soviet prototype), the algorithm is the same up to the fifth point inclusive. Then you need to do the following:

do not remove the bar, but carefully lift and move to the side;

before disconnecting the conductor, you need to push it out of the button body and remove it to the right;

take out the electric motor;

remove the oil seal from the engine shaft;

free the shields from rubber shock absorbers;

remove the spring from the groove inside the device to remove the button;

unscrew the two screws hidden under the rubber ring on the bottom to disconnect the power cord from the case.

Straume 3 is another coffee grinder made in Riga during Soviet times. And here's how she understands you can watch the video:

Basically, all coffee grinders are easy to disassemble. Usually it is enough to unscrew 2-3 screws from the bottom of the case. Sometimes you have to tinker with the latches. But there are also secrets, like a model Bork j700: to get to the printed circuit board, you need to remove the grind switch knob, which is attached instead of the nut with a washer (it is this that needs to be unscrewed). The original opening is also characteristic of the coffee grinder Elmaz... The nuance lies in the fact that you first need to turn the bottom with your palm, and then remove it from the hooks in the body.

Advice! Separately, we can say for the model Vitek 1540... It is not recommended to disassemble it at home. This can only be done by qualified service technicians.

The following will describe methods for repairing coffee grinders that do not require in-depth knowledge. Namely:

the device does not turn on;
knives spin unevenly;
malfunctions in the motor;
break in the power cord;
other typical simple breakdowns.

When the device shows no signs of life, then first of all you should look for a violation of contacts and wire breaks. If the inspection did not reveal a problem, then the reason lies in the electric motor, which can only be eliminated in the workshop, since special knowledge is needed.

Important! When the knives are spinning with sticking, then there is an obvious fault of the burned-out motor winding.At home, for a person ignorant of such matters, rewinding the winding is simply not realistic.

But if the motor works with effort and there is a burning smell, you can try to do without a specialist. Most likely this is due to contamination of bearings or sleeve bushings. To fix the problem, you need to free the shaft and wipe it with alcohol. In case of obvious corrosion, you can treat it with WD-40 or neatly with a sandpaper. For interruptions in engine operation, brushes may be responsible. In this case, cleaning or their complete replacement is required. You can wipe the entire manifold with alcohol if dirt has accumulated on it.

Break points and breaks at the power cord immediately catch the eye. If it is not possible to replace it with a new one, then the wires at the break point should be stripped, re-soldered and re-insulated. There are also cases when, due to contamination of the push mechanism, the blocking fails. This issue can be easily solved by disassembling and cleaning the non-working unit.

Advice! Some grinders (notably the Delonghi KG 79) have a weak link in the form of a capacitor on the electrical board. Over time, it swells up and needs to be replaced with a new one.

In order for the coffee grinder to work as long as possible, you need to follow simple rules of operation and prevention..

Do not leave ground coffee in the device for a long time.
After every grinding need to wipe the inner bowl and knives with a damp cloth.
Do not immerse the device in water when washing, it is better to limit yourself to a wet rubdown.
Machines with plastic enclosures can overheat and fail after long continuous operation. Such failures are frequent with the brands Moulinex and Saturn. If take short breaks in grinding every 20 seconds, the service life of the grinder can be increased.
Need to try to avoid chopping other foods... There is a blender for this.
Should timely change dull knives and millstones... The latter must be replaced after grinding 300 kg of grains, and the former much more often.

Fulfilling simple rules for the care and operation of the device, regularly carrying out preventive work and timely performing minor repairs, you can extend the life of your favorite coffee grinder, which will delight you with many years of faithful service.

The first mentions of coffee in Russia are found in documents from the middle of the 17th century, during the reign of Tsar Alexei Mikhailovich. Emperors Peter I and Catherine the Great were coffee fans. The quality of an invigorating drink is very much dependent on the grinding: fine dust will increase the bitterness, large particles will make the coffee watery. What are the types of coffee grinders, how to grind beans correctly? What are the malfunctions of coffee grinders, how to carry out a simple repair of a coffee grinder with your own hands?The birth of the electric coffee grinder is marked in history on April 3, 1829. On this day, James Carrington received a patent for his electromechanical invention. Up to this point, coffee was ground manually, using a manual coffee grinder. Its device was a reduced copy of a mill, and coffee beans were ground by grinding them between two millstones. With the use of an electric motor, two designs of coffee grinders appeared. In one, all the same traditional millstones are used, and this type is called a millstone. In another, metal knives rotating at high speed took on the role of the grinder and therefore the coffee grinder is called rotary.The millstone type of a coffee grinder consists of three sections. Whole grains are poured into one. In the second, they are ground and poured into the third section on their own in the form of a ready-to-use powder.