Do-it-yourself Ts4342 avometer repair

I got it on the collapse of a not expensive C4342 brought it home, inserted the batteries and the protection does not work as expected. the protection enable button is fixed in the pressed position, but the protection test button does not turn off. Please help me find the problem. The device is not soldered, there are no visible burners, and it seems to do everything, I'm afraid to burn it without protection. The setting of the relay was twisted - it does not help. On the contacts of the relay, it appears and disappears about 0.13V when the test button is pressed, it rises to 0.25V

wzgick, Why google the schematic? There are a lot of offers!

Make an analogue of IC protection on a loose basis.

do you think the microassembly is dead?

Why google it? I have it on paper

Can't it be because of the dried C4?

wzgick, Have you tried it and what is the result?

So far, only aimed at him. There, I have no such nominal 50mkF, and in general, in my opinion, now the closest one can be found only at 47mkF.
What do you think is critical?

There is an adjusting screw on the electromagnet of the protection mechanism, which is locked by paint.
adjust!
If the defect is caused by a microcircuit, the button will not be fixed
will!

STIPLER, if IF, then yes. However, to cut off all “if” the elementary disconnection of the winding helps: with its help, the contact is OPENED, and kept closed by itself (with the help of the magnetic system). However, yes - turn off the coil and check whether the button will be held down - the idea is quite in the subject, half of the possible reasons for the questions will disappear right away.

ADDED 15/02/2013 19:55 PM

Wai .. Wrong topic. In this - not released the check button, and I, according to old memory - “Button not fixed... “Sorry, my comments are not in this place.

The above adjustment can, if desired, achieve
complete non-fixation. In principle, there are two of them:
1-core of the coil itself-coarse reg.
2-see above.
the trigger level is highly dependent on the batteries

When the button is pressed on the relay coil, about 2 volts should appear. If the button is not pressed, nothing on the relay! The button bluntly supplies power to the coil. If there is no battery or an open circuit.
Are the batteries new? Do they hold the current? Does the resistance measurement work?
Profile

Nice device. But the protection is very sensitive. For this reason .. those circuits where the RF component cannot be measured is triggered instantly. In such cases, the second, Chinese, is in the wings.

Something was similar. Eliminated by adjusting the mechanics of the relay, after having shoveled everything around. There is an adjusting screw.

wzgick,
Just measure the voltage on the relay coil at the moment you press the button for checking the health of the protection - what is there? It does not depend on the microcircuit, the power to the relay is supplied directly from the batteries. And then we will tell you. And the profile, please!

By the way, there is a section on measuring instruments

It is necessary for the protection to work as it should!
Everything works fine, just as it was done at the plant, it should be so.

The appliance was put back until. in short, when free time appears, all switches are flushed with a contact cleaner and the non-polar capacitor is replaced.
Protection is fixed without batteries, but when power is applied, it is immediately triggered. Who faced this?

Of course fixed

Accidentally, the button (strip) for checking the protection is not pressed? We do not insert the batteries and check the low current in all switch positions. It immediately triggers in case of faulty shunts (low resistance resistors) or in case of a malfunction of the KMP microcircuit.

They don't guess here. open the diagram and see.

profile, pliz

What's in your profile? Olsa is not nuno to run after me with an ax! I will fill in the truncation.

A hundred pounds knop does not affect. All the cutters are without markings, Oh, the feeling in general is such that they did not use it. Perhaps they immediately killed and thrown into the box.

It's just easier for me to repair than to tell

Become the input of the microcircuit - what comes there?
Become another multimeter on the input. tester terminals - measure the resistance of the shunts (in the high current range, there is a small resistance, we switch to a lower current - the resistance grows approximately as many times, there should be no breaks and repetitions). So check the entire current.
Check the tester readings (all current) by feeding from the calibrator.

Adjustment of the protection actuation level

First you need to measure what comes to the relay coil.

If it comes around 2 V then do not do it
And so the tester would go to the master until the head slammed, turning over again

Well profile

Maybe you're on the next street and I'll make you for a beer, or for a box of beer

Combined electrical measuring device Ts4342 (hereinafter the device) with automatic protection against electrical overloads is designed to measure the strength and voltage of a direct current, the effective value of the strength and voltage of an alternating current of a sinusoidal form, resistance to direct current, parameters of transistors with a power of up to 150 mW

(Ievo is the reverse current of the collector junction, Ievo is the reverse current of the emitter junction. Ices is the initial current of the collector, h21E is the static current transfer coefficient in a circuit with a common emitter).

The device is manufactured for intra-union and export deliveries. Export deliveries are carried out in climatic versions UHL4 and 04.2.

Working climatic conditions of use - ambient temperature from minus 10 to plus 40 ° С, relative air humidity up to 90% at a temperature of 30 ° С.

Ts4342 device can be used in the regulation, repair and operation of electrical and radio equipment in rooms with artificially controlled climatic conditions, for example, in closed heated or cooled and ventilated industrial and others, including well-ventilated underground rooms (no direct exposure to solar radiation and no exposure to sand and dust from the outside air).

The final values ​​of the measuring ranges, the values ​​of the limits of the permissible basic errors (under normal conditions of use of Table 2), the values ​​of the consumed current and the voltage drop at the terminals of the device correspond to Table. one.

Measured value

permissible

errors,

End value

measuring ranges

Note. The limits of permissible basic errors of the device (γ) are expressed as a percentage of the normalizing value (Xn) in the form of reduced errors according to the formula:

where Δ - absolute error;
Xn —Normalizing value equal to the end value of the measurement range when measuring current and voltage, when measuring resistance and "h21E" to the length of the scale of the corresponding measurement range. Scale length value, mm, not less:

Power supply voltage:

automatic protection and ohmmeter circuits

The frequency range of the device when measuring the strength and voltage of alternating current corresponds to tab. 3.

region
frequencies, Hz

The time for establishing the operating mode and instrument readings does not exceed 4 s after switching on. The device allows continuous operation for 16 hours in measurement ranges that do not require power supplies.
Continuous operation of the device in the measurement ranges requiring power supplies (ohmmeter and measurement of transistor parameters) is determined by the rated capacity of these sources and the device consumption (Table 1), but not more than 16 hours.

Insulation between all insulated electrical circuits and the case, as well as external controls of the switching and regulating elements of the device in normal climatic conditions of use (tab. 2) withstands for 1 min. the action of the test voltage with a value of 3 kV (r.m.s.) of alternating current with a frequency of 50 Hz. The device can withstand short-term electrical overloads, the values ​​of which do not exceed 25 times the final value of the measurement range, but not more than 50 A in series and 2 kV in parallel electrical circuits. Overload time 0.2–20 s with an interval of 20 s.

However, based on the specifics of constructing a circuit for measuring the parameters of conductivity transistors of the p-p-p type, it should be borne in mind that when the "p-p-p" button is turned on, the protection circuit is turned off and the device is not protected from overloads.

Note In the absence of an automatic protection power supply, transient overloads (test current or voltage) must not exceed in the measuring range:

up to 1 A - 5 I number;
St. 1 A - 2.5 (1 A + I nom):
up to 100 V - 5 U iom;
St. 100 V - 2 U nom (io no more than 2 kV),

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hello guys, can anyone post here a diagram of c 4342 but do not waste time on c 4342 m -1 they (diagrams) do not match
I nechaino measured the AC voltage in the resistance measurement mode, after which, with each measurement, the device goes off scale

please answer those with a diagram
thanks in advance

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Group: Participant
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User #: 108807
Registration: 12-December 14
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Partner in crime

Group: Participant
Posts: 1060
User #: 108807
Registration: 12-December 14
Residence: 056 RU

Group: Participant
Posts: 9
User #: 109707
Registration: 11-February 15

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Can

This post has been edited tehnik315 - Feb 11 2015, 08:09 PM

Attached file (Number of downloads: 1035)

________4342.zip

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Another, one scheme

Attached file (Number of downloads: 765)

______4342.zip

• 

Is your TV, radio, mobile phone or kettle broken? And you want to create a new topic about this in this forum?

First of all, think about this: imagine that your father / son / brother has an appendicitis pain and you know from the symptoms that it is just appendicitis, but there is no experience of cutting it out, as well as the tool. And you turn on your computer, access the Internet on a medical site with the question: "Help to cut out appendicitis." Do you understand the absurdity of the whole situation? Even if they answer you, it is worth considering factors such as the patient's diabetes, allergies to anesthesia and other medical nuances. I think no one does this in real life and will risk trusting the life of their loved ones with advice from the Internet.

The same is in the repair of radio equipment, although of course these are all the material benefits of modern civilization and in case of unsuccessful repairs, you can always buy a new LCD TV, cell phone, iPAD or computer. And for the repair of such equipment, at least it is necessary to have the appropriate measuring (oscilloscope, multimeter, generator, etc.) and soldering equipment (hairdryer, SMD-hot tweezers, etc.), a schematic diagram, not to mention the necessary knowledge and repair experience.

Let's consider a situation if you are a beginner / advanced radio amateur soldering all sorts of electronic gizmos and having some of the necessary tools. You create an appropriate thread on the repair forum with a short description of “patient symptoms”, ie. for example “Samsung LE40R81B TV does not turn on”. So what? Yes, there can be a lot of reasons for not switching on - from malfunctions in the power system, problems with the processor or flashing firmware in the EEPROM memory.
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Here you go -

sorry, this is also on the M1, but the principle of operation they all have one to one, that 4342 has M1, that 4353, that yours.

apparently yours -

P.S. if, with the batteries installed, the protection button is not fixed - the PPC is a tricky micro-assembly (it is responsible for protection), xs as it is now, but in the 90s it was in short supply 🙂

Everyone should be recorded. If only this is a malfunction, it can be disassembled and repaired. There are ordinary P2K switches, you can figure it out, you will see how to fix it.

Not all. Protection is fixed only with working batteries.Charge indication protection off button - not fixed at all.
PS: The main thing is not to forget to turn off the protection - it really loves to discharge the batteries.

You can find everything now, including KMP20UP1A.

Does the protection enable button “stick” when the batteries are removed?

I didn't mean shops.
You can find it in organizations where there are services involved in the verification, repair of measuring instruments.
Quite a lot of them are written off due to the transition to new types of measuring instruments.
And the repair of faulty ones is often unprofitable, for example, when the stretch wires of the current measuring frames break when the device falls, burned out current shunts.
(Young people especially "love" to shoot them)
Personally, I myself do not like them for the inconvenience in working with them (switching from one type of measurement to another takes a lot of time), the relative complexity of working with them, insufficient measurement accuracy, low input impedance.

Added after 4 hours 35 minutes

... Protection is fixed only with working batteries.
The protection activation button in a working device must be fixed without batteries.
There is a magnet and an anchor, the coil only serves to unlock the armature when the protection is triggered.
Power is supplied to it from the KMP20UP1A output only at the moment of protection operation.

Does the protection enable button “stick” when the batteries are removed?

Nope does not stick, only the right ones work - switches of the kind of work.
When I was taking it apart, I noticed that there was a magnet, and when this button was pressed, it all the same returns to its original position. Maybe the batteries are just dead, I have not tried to put the normal ones yet.
I measured the voltage from the battery, it shows normal, but the resistance: mda: The reality read in the instructions does not correspond to: pardon:
I took it from a friend for a while, I just don't want to spend money on a multimeter, but I feel I can't really measure it =)

ORDER TABLE:

BONUSES:

Design and support:
Aleksandr Kuznetsov

Technical support: Mikhail Bulakh

Programming: Danil Monchukin

Marketing: Tatiana Anastasyeva

Translation: Natalia Kuznetsova

When using materials from the site, a link to https://my.housecope.com/wp-content/uploads/ext/3265 is required

made in Ukraine

Schematic diagrams and service manuals

Domestic combined devices

The following documentation may be available for the C4342 meter:

Schematic diagram of the combined instrument C4342 (order) (download)

Repair and adjustment manual for the combined instrument C4342 (order) (download)

Operating instructions for the combined instrument C4342 (order) (download)

You can always order a circuit diagram for the combined device C4342.

The possibility of ordering a manual for repair and adjustment, as well as operating instructions for the combined device Ts4342, please specify additionally.

Recommended to download in our Free Technical Library:

The resistances in the tester are wound with a wire - called "MANGANIN", has a yellowish tint of varnish insulation.

Disassembled the avometer and did not find a single wirewound resistor. It looks like all MLT and S2-29. Photo of the board as a whole from the side of the details. Look pliz. In which direction to look?

Cheto's photo did not go. Uploaded here
280 kilobytes

You are in luck, not a single resistor has charred to such a state that you cannot see the value.
I would take another device for measuring resistances, and would measure the resistances of all resistors of the faulty tester, I would first disconnect the battery from the tester, and turn it on to the measurement limit of 1000 V, constant. The tester should also have latching switches, press them all.
If the result of measuring the resistance of one of the resistors is more than what is written on the resistor, then evaporate it and check the resistance again.

Alex s:
Let's try it!
By the way, when I had to repair the avometer after such measurements, there were breakdowns, every time, between the switch terminals. He gouged out the coal and filled it. so that there was varnish, rosin, glue, epoxy, etc.

It is likely that the printed circuit board will be charred and burned out.The photo was taken only from the side of the details, it is not visible on it.
We'll have to carefully remove everything from the case and inspect.

The avometer was repaired. The problem was with resistor R40.
It should be 673 ohms, and when it dropped out there were several tens of kilo-ohms.
I found a 679 Ohm resistor and in parallel picked up 111 Kilo Ohm.
Compared measurements with a digital avometer. It seems to measure exactly.
But how will it be measured when the temperature changes?

Once, at work, they tried to lower the MLT resistors into Dewar with liquid nitrogen, now I remember that there was no significant resistance drift, superconductivity, it usually sets in abruptly, at a certain temperature, depending on the material.

So you have nothing to fear, with new resistors the temperature stability of the meter will not change.

Name: Repair of combined devices.

author: Kuzin V.M., Kuzina O.V.

The principle of operation, design, characteristics and basic rules for the use of combined devices are considered. Basic electrical diagrams, layout diagrams of elements, maps of electrical circuits and other information about domestic and most common foreign combined devices are presented. Practical recommendations for troubleshooting and troubleshooting are given. Proposed for repetition by radio amateurs, developed by the authors and implemented in practice, circuits of original measuring devices.

In the practice of measuring, portable combined devices have become widespread, which make it possible to measure several physical magnitudes over a wide range of values. The capabilities of portable combined devices can be realized most fully under the condition of correct operation and taking into account the influence of their characteristics on the measurement results, which requires, first of all, familiarity with the theory of measurements and the availability of the necessary information about combined devices as measuring instruments.
During the operation of portable combined devices, various types of malfunctions may occur, caused both by wear and tear of system elements, and by improper actions of the operator. When repairing these devices, difficulties are possible associated with the lack of element marking on circuit boards or blocks, element arrangement diagrams and other necessary information.

It is quite within the power of every user who is well acquainted with the basics of electronics and electrical engineering to independently organize and repair the multimeter. But before embarking on such a repair, you must try to figure out the nature of the damage that has occurred.

It is most convenient to check the serviceability of the device at the initial stage of repair by inspecting its electronic circuit. For this case, the following troubleshooting rules have been developed:

• it is necessary to carefully examine the printed circuit board of the multimeter, on which there may be clearly distinguishable factory defects and errors;
• special attention should be paid to the presence of unwanted shorts and poor-quality soldering, as well as defects on the terminals at the edges of the board (in the area of ​​the display connection). For repairs, you will have to use soldering;
• factory errors most often manifest themselves in the fact that the multimeter does not show what it should according to the instructions, and therefore its display is examined first of all.

If the multimeter gives incorrect readings in all modes and IC1 heats up, then you need to inspect the connectors to check the transistors. If the long leads are closed, then the repair will consist only in opening them.

In total, a sufficient number of visually detectable faults can accumulate. You can familiarize yourself with some of them in the table and then eliminate it yourself.(to the address: Before repairing, it is necessary to study the multimeter circuits, which are usually given in the passport.

If they want to check the serviceability and repair the multimeter indicator, they usually resort to using an additional device that issues a signal of a suitable frequency and amplitude (50-60 Hz and units of volts). In its absence, you can use a multimeter type M832 with the function of generating rectangular pulses (meander).

To diagnose and repair the multimeter display, you need to remove the working board from the device case and select a position convenient for checking the indicator contacts (screen up). After that, you should connect the end of one probe to the common terminal of the indicator under investigation (it is located in the bottom row, on the far left), and alternately touch the other end to the signal outputs of the display. In this case, all its segments should light up one after the other according to the wiring of the signal buses, which should be read separately. Normal "operation" of the tested segments in all modes indicates that the display is working properly.

Additional Information. The indicated malfunction most often manifests itself during the operation of a digital multimeter, in which its measuring part fails and needs to be repaired extremely rarely (provided that the instructions are followed).

The last remark concerns only constant values, when measuring which the multimeter is well protected against overloads. Serious difficulties in identifying the reasons for the failure of the device are most often encountered when determining the resistances of the circuit section and in the dialing mode.

In this mode, typical malfunctions, as a rule, appear in the measuring ranges up to 200 and up to 2000 Ohm. When an extraneous voltage enters the input, as a rule, resistors under the designations R5, R6, R10, R18 burn out, as well as the transistor Q1. In addition, the capacitor C6 often breaks through. The consequences of exposure to extraneous potential are manifested as follows:

1. when the Q1 triode is completely "burnt out", when determining the resistance, the multimeter shows one zeros;
2. in case of incomplete breakdown of the transistor, the device with open ends should show the resistance of its junction.

Note! In other measurement modes, this transistor is short-circuited and therefore has no effect on the display.

With a breakdown of C6, the multimeter will not work at the measuring limits of 20, 200 and 1000 Volts (the option of a strong understatement of the reading is not excluded).

If the multimeter constantly beeps when dialing or is silent, then the reason may be poor-quality soldering of the pins of IC2. The repair consists in careful soldering.

Inspection and repair of an inoperative multimeter, the malfunction of which is not related to the cases already considered, is recommended to start with checking the voltage of 3 Volts on the ADC supply bus. In this case, first of all, it is necessary to make sure that there is no breakdown between the supply terminal and the common terminal of the converter.

The disappearance of indication elements on the display screen in the presence of a supply voltage converter with a high degree of probability indicates damage to its circuit. The same conclusion can be made when a significant number of circuit elements located near the ADC are burned out.

Important! In practice, this node "burns out" only when a sufficiently high voltage (more than 220 Volts) hits its input, which manifests itself visually in the form of cracks in the module compound.

Before talking about repairs, you need to check. A simple way to test the ADC for suitability for further operation is to dial its terminals using a known working multimeter of the same class. Note that the case when the second multimeter incorrectly shows the measurement results is not suitable for such a check.

When preparing for operation, the device is switched to the diode “dialing” mode, and the measuring end of the wire in red insulation is connected to the “minus power” output of the microcircuit. Following this black probe, each of its signal legs is sequentially touched.Since there are protective diodes at the inputs of the circuit, connected in the opposite direction, after applying a forward voltage from a third-party multimeter, they should open.

The fact of their opening is recorded on the display in the form of a voltage drop across the junction of the semiconductor element. Similarly, the circuit is checked when a probe in black insulation is connected to pin 1 (+ ADC power supply) and then touching all other pins. In this case, the indications on the display screen should be the same as in the first case.