Quite often, such a nuisance occurs as a wire (cable) breaking near the plug. This happens especially often with wires that are subject to constant vibrations and movements. For example, with headphones chargers, multimeter probes and the like. We notice the gap, as a rule, only after the thing we are using stops working. And it’s actually quite difficult to notice this. If only by chance we see... The break does not occur immediately, with the exception, of course, of a rough mechanical impact. The cable braid is usually damaged first.
Hi all! I would like to share a method for making reliable probes. When I bought the DT9208A multimeter, it came with probes, but they were made very poorly and soon became unusable. The weakest point of these probes is where the wire enters the plastic tube. There is no wire fixation at this point and if you accidentally pull the cable without applying much force, it will come off. This is what happened with my probes. So here’s some advice: to prevent the cable from coming off, you need to fix it. This can be done using regular electrical tape or adhesive tape.
But if you have the opportunity, it is better to buy high-quality branded probes or, like me, do it yourself. So, we will need:
Soviet plug. You can use another one, but it is better to be made in the USSR, since Soviet plugs have brass pins. It is not difficult to find such a fork; in extreme cases, you can buy it on the market. You can use this option. The main thing is to pay attention to the metal from which the pins are made.
When you find such a fork, you need to remove the brass pins from it. This is very simple to do: to do this, you need to unscrew the bolts from the top of the fork, and it will split in half. Next you need to unscrew the pins themselves. This is what the pins from my plug look like:
As I already said, we will take the base from the old probes that came with the kit. Namely, we need a plastic tube into which we will insert the pins from the plug. To do this, we need to remove the old probe pins with pliers. This is what you should end up with:
So, we have pins from the fork and plastic tubes from old probes. Now we need to prepare the pins for inserting into the tubes. As we can see, the pins are not straight, but in the shape of an “G”, so you need to cut off the excess with a hacksaw. Or rather, the part that is bent. In addition, we need to sharpen the pins. This can be done using a file or sharpening machine. We process them in such a way that they fit tightly into the plastic tube.
Next, we need to decide which wire we will use for the probes. I went to the radio market and chose the right one. It is better to take a wire with a thick copper core. The only such wires on our market were double speaker wires.
If you also bought double wire, it must be carefully divided into two using a blade or knife. Also, when purchasing a wire, you should select correct length. I bought a wire 1.5 meters long, although my original probes had a wire less than a meter. I don’t know about you, but I find it more convenient when the wire is long. So choose the length of the wire based on your own considerations, but not shorter than 0.7 meters, as it will be very inconvenient to use such probes.
When you go to buy wire, don't forget to buy plugs for connecting the probes. When purchasing plugs, take a multimeter with you to check whether the plug fits your device or not. But most multimeters will accept banana plugs. I bought these:
Now we have everything we need to make probes. The first step is to separate and strip the wire. Then tin all soldering points, i.e. the ends of the wires and the ends of the pins where the wire will be soldered. There is no need to tin the plugs, since the wire is inserted into them and clamped with a bolt.
Once everything is ready for assembly, thread the wire through the plastic tube and solder the brass pin to it. Then you need to pull the wire back so that the pin is inserted into the tube. Now you need to fix the place where the wire enters the tube and the place where the pin enters the tube. I did this using heat shrink.
The red probe turned out to be a little crooked because the wire was soldered not in the center of the pin, but on the side. But this does not affect the work in any way.
Now all we have to do is thread the other end of the wire into the connector and tighten the wire with a bolt and the probes are ready for use.
These are the probes I got:
The resistance of the probes was 0.6 Ohm, which is pretty good. The resistance of the original probes was about 1 Ohm, since the wire was thinner.
These are the kind of probes you can make with your own hands without special costs. Before buying probes, think about whether it would be cheaper for you to make them yourself? But if you are soldering SMD elements and you need thinner ends of the probes (like needles), then you can sharpen the brass pins () more strongly. Of course, if you have the opportunity to buy expensive branded probes, then buy them, but I decided to save money and buy parts. In addition, our market prices are very high. Good luck to all! Especially for - Kirill.
Discuss the article DIY MULTIMETER PROBE
Every owner of a Chinese multimeter DT830 and similar models must have encountered some inconveniences during operation that are not visible at first glance.
For example, the battery constantly drains due to the fact that they forgot to turn the switch to the off position. Or lack of backlighting, impractical wires and much more.
All this can be easily modified and the functionality of your cheap multimeter can be increased to the level of individual professional foreign models. Let's consider in order what is missing and what can be added to the operation of any multimeter without special capital costs.
Replacing multimeter wires and probes
First of all, what 99% of users of cheap Chinese multimeters encounter is the failure of low-quality measurement probes.
Firstly, the tips of the probes may break. When touching an oxidized or slightly rusty surface for measurement, the surface must be lightly cleaned to ensure reliable contact. The most convenient way to do this is, of course, using the probe itself. But as soon as you start scraping, at that moment the tip may break off.
Secondly, the cross-section of the wires included in the kit also does not stand up to criticism. Not only are they flimsy, but this will also affect the error of the multimeter. Especially when the resistance of the probes themselves plays a significant role during measurements.
Most often, a wire break occurs at the connection points at the plug-in contact and directly at the soldering of the sharp tip of the probe. 
When this happens, you will be surprised how thin the wiring inside is really. 
Meanwhile, the multimeter must be designed to measure current loads up to 10A! It is not clear how this can be done using such a wire. 
Here are real current consumption measurements for flashlights, made using standard styli included and with homemade probes cross section 1.5mm2. As you can see, the difference in error is more than significant. 
The plug-in contacts in the multimeter connectors also become loose over time and worsen the overall resistance of the circuit during measurements.
In general, the unequivocal verdict of all owners of DT830 multimeters and other models is that the probes need to be modified or changed immediately after purchasing the tool. 
If you are the lucky owner lathe or you have a familiar turner, then you can make the probe handles yourself from some insulating material, for example pieces of unnecessary plastic.
The tips of the probes are made from a sharpened drill. The drill itself is a hardened metal and can be used to easily scrape off any carbon deposits or rust without the risk of damaging the probe. 
When replacing plug-in contacts, it is best to use the following plugs used in audio equipment for speaker sockets. 
If you really are on a collective farm or there are no other options at hand, then as a last resort you can use ordinary contacts from a collapsible plug.
They also fit perfectly into the connector on the multimeter. 
At the same time, do not forget to insulate the ends that will stick out outside the multimeter, in the places where the wires are soldered to the plug, with a heat pipe.
When it is not possible to make probes yourself, the body can be left the same, replacing only the wires.
In this case, three options are possible:
After replacement, such wires will very easily be collected into a bundle without getting tangled.
Secondly, they are designed to withstand a huge number of bends and will break no sooner than the multimeter itself fails.
Thirdly, the measurement error due to their larger cross-section compared to the original ones will be minimal. That is, there are continuous advantages everywhere.
If you make long wires up to 1.5 m, taking into account all the connections, the resistance on them can reach several ohms!Important note: when replacing wires, you should not try to make them much longer than those that came with the kit. Remember that the length of the wire, as well as its cross-section, affects the overall resistance of the circuit.
Those who do not want to do homemade products can order ready-made, high-quality silicone probes with many tips on AliExpress. 
To ensure that new probes with wire take up minimal space, you can twist them into a spiral. For this new wire it is wound around the tube, wrapped in electrical tape to secure it, and the whole thing is heated with a hair dryer for a couple of minutes. As a result, you get this result. 
In a cheap version, this trick will not work. And when used for heating construction hair dryer insulation may even float.
Refinement of the multimeter mount
Another inconvenience when taking measurements with a multimeter is the lack of a third hand. You constantly have to hold a multimeter in one hand and use the other to work with two probes at the same time. 
If measurements take place at your desk, then there is no problem. Put the tool down, free your hands and work. 
What should you do if you measure the voltage in a panel or in a distribution box under the ceiling?
The problem can be solved simply and inexpensively. In order to be able to mount the multimeter on a metal surface, on back side device using hot glue or double-sided tape, glue ordinary flat magnets. 
And your device will be no different from expensive foreign analogues. 
Another option for inexpensive modernization of a multimeter in terms of its convenient placement and installation on a surface for measurements is manufacturing homemade stand. To do this, you only need 2 paper clips and hot glue. 
And if you don’t have any surface nearby where you can place the tool, what should you do in this case? Then you can use an ordinary wide elastic band, for example from suspenders. 
You make a ring out of an elastic band, pass it through the body and that’s it. Thus, the multimeter can be conveniently mounted directly on your hand, like a watch.
Firstly, now the multimeter will never fall out of your hands again, and secondly, the readings will always be before your eyes. 
Caps for probes
The spikes at the ends of the probes are quite sharp, which can hurt you. Some models come with protective caps, some do not. 
They also get lost quite often. But in addition to the danger of pricking your finger, they also protect the contacts from breaking when the multimeter is in a bag mixed with another tool.
In order not to buy spare ones every time, you can make them yourself. Take an ordinary cap from a gel pen and lubricate the tip of the dipstick with any oil. This is done so that the cap does not stick to the surface during the manufacturing process.
Then fill inner surface hot glue the cap and place it on the sharp tip. 
Wait until the hot glue hardens and calmly remove the resulting result. 
Multimeter backlight
A function that the multimeter lacks in poorly lit areas is display backlighting. Solving this problem is not difficult, just apply:
Make a hole in the side of the housing for the switch. Glue the reflector under the indication display and solder two wires to the crown contacts. 
They supply power to the switch and then to the LEDs. The structure is ready.
The final result of a homemade modification of the multimeter backlight will look like this: 
The backlit battery will drain much faster, so be sure to turn off the switch when natural light will be quite enough.
Replacing the crown in a multimeter with a lithium-ion battery from a phone
IN last years It has become very popular to remake a multimeter by replacing the power supply from the original crown with a lithium ion battery from cell phones and smartphones. For these purposes, in addition to the battery itself, you will need charging and discharging boards. They are bought on Aliexpress or other online stores. 
The overdischarge protection board for such batteries is initially built into the battery in its upper part. It is needed to prevent the battery from being discharged beyond its nominal value. acceptable standards(about 3 Volts and below). 
The charging board does not allow you to recharge the battery above 4.2 Volts (link to aliexpress). 
In addition, you will need a board that increases the voltage from 4V to the required 9V (link to aliexpress). 
The battery itself fits compactly on the back cover and does not interfere with its closure. 
First, the output voltage on the boost module must be set to 9 Volts. Connect it with wires to a multimeter that has not yet been converted and use a screwdriver to unscrew the required value. 
You will have to make a hole in the case for a micro or mini USB charging connector.
The boosting module itself is located in the place where the crown should be. 
Be sure to ensure that the wiring from the module to the battery is of the required length. In the future, this will allow you to easily remove the cover and, having halved the body, carry out an internal inspection of the multimeter if necessary.
After placing all the parts inside, all that remains is to solder the wiring according to the diagram and fill everything with hot glue so that nothing moves when moving the device. 
It is advisable to fill not only the body with hot glue, but also the contacts with the wires in order to extend their service life. 
A significant drawback of such a multimeter on a lithium-ion battery is its operation, or rather not operation, at subzero temperatures.
Once your multimeter sits in the trunk of a car or in a bag in the winter for a long time, you will immediately remember the battery.
And you might think, was such a change useful? Ultimately, of course, you decide, based on the operating conditions of the device.
Refinement of the on/off button on the multimeter
It is advisable to further improve the last option for refining the multimeter with the transition to lithium-ion batteries by placing a shutdown button in the power supply circuit of the converter to the battery. 
First, the converter itself consumes a small amount of current, even in standby mode when the multimeter is not working.
Secondly, thanks to this switch, you won’t have to click the multimeter itself again to turn it off. Many devices fail prematurely because of this reason.
Some paths are erased ahead of time, others begin to shorten each other. So a button to turn off the entire device at once will be very useful.
Another tip from experienced users of Chinese multimeters is that in order for the switch to serve for a long time and properly, immediately after purchase, disassemble and lubricate the sliding areas of the switch balls. 
And on the board it is recommended to coat the tracks with technical Vaseline. Since new devices do not have lubrication, the switch wears out quickly. 
You can make a button like an internal one, if you find it free place, and in the external. To do this, you will have to drill only two micro holes for the power wiring. 
Flashlight in multimeter
Another innovation for the multimeter - additional option flashlight. Often you have to use the device to look for damage in switchboards and distribution cabinets in basements, or short circuits in wiring in rooms where there is no light.
An ordinary white LED and a button specifically for turning it on are added to the circuit. It is very easy to check how much luminous flux from a given LED is enough. You don't even have to disassemble it to do this.
Place the anode leg of the diode in connector E, and the cathode leg in connector C (the anode leg is longer than the cathode). All this is done in the connectors for the transistor measurement mode on the P-N-P block. 
The LED will glow in any position of the switch and will go out only when you turn off the multimeter yourself. To mount all this inside, you need to find the necessary pins on the circuit board and solder two wires to the emitter (connector E) and collector (connector C). A button is soldered into the wire gap and mounted through a hole in the multimeter body. 
You secure everything with hot glue and you get a portable flashlight-multimeter.
Despite the fact that multimeters are always equipped with probes, in inexpensive models measuring instruments(DT 181, DT 182, DT 832, etc.) their quality leaves much to be desired. The result does not take long to arrive. It happens that not even a month passes before the owner discovers that it is impossible to take measurements with the device, because a wire has broken in one of the plugs or tips. Figure 1 demonstrates typical problem, characteristic of inexpensive Chinese products.
Figure 1. Broken wire – typical fault for Chinese productsOf course, it is not difficult to fix such a malfunction, but this will not solve the problem as a whole, and a new break will not be long in coming. This means it’s time to purchase high-quality and reliable multimeter probes, for example, Mastech products (T3033, T3009, E3029, etc.) or S-Line (ETL-5, ETL-10, ETL-11).
For the sake of fairness, it should be noted that among the products of unknown manufacturers from the Middle Kingdom, you can find quite decent analogues that will be reliable and, at the same time, in no way inferior to the original products. But to do right choice, you need to know what design features you should pay attention to. let's consider Various types test leads to determine their advantages and disadvantages. Let's start with inexpensive products.
Measuring probes, in which the wires are PVC insulated, plastic is used as the material for plugs and holders, and the tips themselves are made of steel, as a rule, the most inexpensive. They are included in the kit for budget models of multimeters, such as DT-838 or DT-830B (see Figure 3).
Figure 3. Inexpensive multimeters are equipped with appropriate probes Usually, test leads are selected different color to correctly connect the device to the circuit being measured.
The standard electrode thickness for such products is 4 mm, and the length varies depending on the model. The shape of the holders may have several variations, but this is insignificant design feature does not affect reliability.
Such products are not the best option, any careless movement may cause the tip to come off. In addition, we should not forget about the disadvantages inherent in PVC insulation, they are as follows:
It should also be noted that stylus tips with needles with a diameter of 4 mm are not suitable for all jobs. For example, to take measurements from electronic boards where SMD components are located, you will need thin probes for the tester.
The only advantage budget models- low price. Such products are fully justified when using a multimeter at a non-professional level, that is, for domestic purposes for minor repairs.
Here are some typical distinctive features, characteristic of a quality instrument:
Products from the following brands meet these requirements: Fluke, Unitrend, Mastech, etc.
Figure 4. Flucke styli complete with crocodile clips Generally good professional probes collapsible, this allows you to use special attachments for them. It makes sense to talk about them in more detail.
Many manufacturers provide connection to test leads different types attachments, which makes the probes universal and significantly expands the scope of their application (see Figure 5).
Figure 5. Test leads and attachment set Thanks to this set, you can choose long or short needles, depending on the need, change the thickness of the tip, for example, when you need to make delicate measurements, etc.
To check SMD components, it is convenient to use a special pliers attachment; testing with it is shown in Figure 6.
Figure 6. Checking the SMD resistor The alligator clip (see Figure 4) is no less useful; it can be used to connect to a device for taking measurements, while during the testing process your hands are freed, which allows you to make other measurements.
Using an attachment that has a spring-loaded hook (Figure 7), you can connect to most attachments on printed circuit boards.
Figure 7. Spring-loaded hook attachment A nozzle with a terminal adapter (Fig.) allows you to easily connect to a laboratory power supply to control voltage and current.
Figure 8. Terminal adapter Concluding the topic of professional measuring leads, you should pay attention to one significant drawback of such products - the relatively high price. For example, original Flucke probes with a set of attachments cost about $60.
It is not at all necessary to buy new test leads if the old ones cannot be repaired. Moreover, it is not difficult to make multimeter probes with your own hands. The result will be somewhat inferior to professional products, but the cost of the products will be disproportionately lower. As for quality and reliability, their level will be no worse than that of their Chinese counterparts.
First of all, you need to purchase high-quality stranded copper wire in silicone insulation. As a last resort, you can use a PVC sheath, but, as mentioned above, such probes will have a lot of disadvantages.
You can use regular fountain pens, felt-tip pens or pencils with replaceable leads as holders. Sewing needles or dart tips from the game Darts are suitable for electrodes.
Figure 9. All that remains is to glue the tip and put on the heat-shrinkable casing Second option: we use a pencil with a replaceable lead as a probe; the role of the tip will be played by a sewing needle. The manufacturing principle is almost the same, only the wire is soldered to a needle.
Related video:
Note that pen caps can be used as protective attachments for such probes.
