Oscilloscope adjustment s1 94 do-it-yourself repair

Bought an oscilloscope C1-94 somehow for repairs (I’ve been thinking about buying such a device for a long time), it’s not new and I got it cheap, although the probe turned out to be homemade there, then I’ll redo it, but still, since the device was rarely used, I decided to sort it out a little and replace what that did not work and gave jambs. So, I found a diagram, studied a bunch of forum information, manuals and several articles. All this took several days for 3-4 hours a day! I had to study a lot of information - this is still not a coffee maker, but a complex measuring device - some beginners also try to repair it, but they immediately rush at it with a soldering iron and the problem cannot be solved here in a couple of hours, you need an approach, knowledge, experience.

Schematic diagram S1-94

In general, to begin with, I will briefly talk about the oscilloscope and its features, pros and cons, and in general my opinion in general. Perhaps there will be a lot of letters here, but I think a device of this category is worth it.

So, the main advantage of this measuring device is that there are no microcircuits and assemblies in it at all. There is practically nothing to repair looking for a rare replacement, repairing a transistor circuit from one of the sides is even better.

Of course, there are several rare elements - such as germanium transistors and other loose trifles in the generator, but it, as a rule, is of high quality and can rarely break.

The oscilloscope is covered with a casing - which can be removed by unscrewing 4 screws and removing the legs with stands, remove the casing, on the frame the main board where almost the entire part of the power supply and other regulatory elements are mounted.

There is also a hinged board that is made like this for ease of installation and repair, and the board is closed with a plastic casing at the back, which is fastened with a screw - and unscrewing which is just tired!

I removed the tube for the convenience of repair - you need to unscrew the clamp by slightly shifting it, as well as the guide latch, which, while sinking, fixed it to adjust the position of the tube.

It is better to mark the socket with a marker, since there is no key on it, and then you can measure the heat for a long time to put it in the right, correct position. The wires are flexible, durable, nothing came off during the repair process, everything was done in good faith - these are not modern delicate Chinese devices, where half of the wiring and part of their fasteners can fall off at the first dismantling. In particular, there was a poor balancing of voltages of 12-0-12 volts (bipolar), there the imbalance should be scanty, but as I did not regulate, it turned out to be about 1 volt.

I started to check the electrolytes, simply soldering them in turn and measuring the capacity of those that I could reach - a couple turned out to be dried up, one new one blew itself up, confusing the polarity of the reverse soldering - the board has very poor markings on the textolite, and if you solder several elements, you can get lost when mounting back .

When the voltage was set in the order of the norm, the balance was the one that was needed, set up the sweep regulators, adjusted all the parameters, performed the calibration as expected, gave a signal from the assembled generator on a popular microcircuit NE555, looked - everything is in order, the device is now what you need.

By the way, you also need to wipe the dust at the oscilloscope - and it’s better to moisten the napkin not in water, but to take something ready-made, soaked in alcohol or other similar means, in order to prevent oxidation of parts and circuit elements.

Switches can be cleaned, and their contacts wiped with acetone so that they shine, and not be black. Then, when they switch the operating modes of the device, there will be no jumps and serious distortions.

When reassembling after repair, we check the position of the tube and put it straight.I am attaching to the article all the diagrams and materials that helped me in the repair of this wonderful service oscilloscope. The repair was done by redmoon.

Repair and adjustment of the oscilloscope C1-94

espec. ws/section6/article95.html

Many specialists, and especially radio amateurs, are well aware of the S1-94 oscilloscope (Fig. 1). The oscilloscope, with its rather good technical characteristics, has very small dimensions and weight, as well as a relatively low cost. Thanks to this, the model immediately gained popularity among specialists involved in mobile repair of various electronic equipment, which does not require a very wide bandwidth of input signals and the presence of two channels for simultaneous measurements. Currently, a fairly large number of such oscilloscopes are in operation.

In this regard, this article is intended for specialists who need to repair and configure the S1-94 oscilloscope. The oscilloscope has a typical block diagram for devices of this class (Fig. 2. It contains a vertical deflection channel (VOC), a horizontal deflection channel (HRT), a calibrator, an electron beam indicator with a high-voltage power supply and a low-voltage power supply.

The CVO consists of a switchable input divider, a preamplifier, a delay line, and a final amplifier. It is designed to amplify the signal in the frequency range of 0. 10 MHz to the level required to obtain a given vertical deviation coefficient (10 mV / div. 5 V / div in steps of 1-2-5), with minimum amplitude-frequency and phase- frequency distortion.

The CCG includes a timing amplifier, a timing trigger, a trigger circuit, a sweep generator, a blocking circuit, and a sweep amplifier. It is designed to provide linear beam deflection with a specified sweep factor from 0.1 µs/div to 50 ms/div in 1-2-5 steps.

The calibrator generates a signal to calibrate the instrument in terms of amplitude and time.

The CRT assembly consists of a cathode ray tube (CRT), a CRT power circuit, and a backlight circuit.

The low-voltage source is designed to supply all functional devices with voltages of +24 V and ±12 V.

Consider the operation of the oscilloscope at the circuit level.

The investigated signal through the input connector Ш1 and the push-button switch V1-1 (“Open / Closed input”) is fed to the input switchable divider on the elements R3. R6, R11, C2, C4. C8. The input divider circuit ensures that the input resistance is constant regardless of the position of the vertical sensitivity switch B1 (“V / DIV.”). Divider capacitors provide frequency compensation of the divider over the entire frequency band.

The signal under study from the KVO preamplifier circuit through the emitter follower cascade on the T6-U1 transistor and switch V1.2 is also fed to the input of the KGO synchronization amplifier for synchronous triggering of the sweep circuit.

The synchronization channel (US block) is designed to start the sweep generator synchronously with the input signal to obtain a still image on the CRT screen. The channel consists of an input emitter follower on a T8-UZ transistor, a differential amplification stage on T9-UZ, T12-UZ transistors and a synchronization trigger on T15-UZ, T18-UZ transistors, which is an asymmetric trigger with emitter coupling with an emitter follower on input on the transistor T13-U2.

The D6-UZ diode is included in the base circuit of the T8-UZ transistor, which protects the synchronization circuit from overloads. From the emitter follower, the clock signal is fed to the differential amplification stage. The differential stage switches (B1-3) the polarity of the synchronizing signal and amplifies it to a value sufficient to trigger the synchronization trigger. From the output of the differential amplifier, the clock signal is fed through the emitter follower to the input of the synchronization trigger.A signal normalized in amplitude and shape is removed from the collector of the T18-UZ transistor, which, through the decoupling emitter follower on the T20-UZ transistor and the differentiating circuit S28-UZ, Ya56-U3, controls the operation of the trigger circuit.

To increase the synchronization stability, the synchronization amplifier, together with the synchronization trigger, is powered by a separate 5 V voltage regulator on a T19-UZ transistor.

The differentiated signal is fed to the trigger circuit, which, together with the sweep generator and the blocking circuit, provides the formation of a linearly changing sawtooth voltage in standby and self-oscillating modes.

As a sweep generator, a circuit for discharging a time-setting capacitor through a current stabilizer was chosen. The amplitude of the linearly changing sawtooth voltage generated by the sweep generator is approximately 7 V. The time-setting capacitor C32-UZ during recovery is rapidly charged through the T28-UZ transistor and the D12-UZ diode. During the working stroke, the D12-UZ diode is locked by the control voltage of the trigger circuit, disconnecting the timing capacitor circuit from the trigger circuit. The capacitor is discharged through the T29-UZ transistor, which is connected according to the current stabilizer circuit. The discharge rate of the time-setting capacitor (and, consequently, the value of the sweep factor) is determined by the current value of the T29-UZ transistor and changes when the time-setting resistances R12 are switched. R19, ​​R22. R24 in the emitter circuit using switches B2-1 and B2-2 (“TIME / DIV.”). The sweep speed range has 18 fixed values. A change in the sweep factor by a factor of 1000 is provided by switching the time-setting capacitors C32-UZ, S35-UZ with the switch Bl-5 (“mS / mS”).

Table 1. MODES OF ACTIVE ELEMENTS ON DIRECT CURRENT

Added (25.12.2015, 15:32)
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After a couple of inclusions, a luminous dot appeared on the screen and that's it. Up, down, side to side you can move it. Brightness control works.

Where can one find such a diode? I mean the old USSR technology.
There is a suspicion that the “mail” dropped the package with the device, as the box was a little wrinkled on one side. Perhaps that is why this error appeared.

No sweep.
According to the totality of signs, a non-solder or a microcrack may occur. Look at the board with a magnifying glass, solder everything that is suspicious. Try to lightly press on the boards with something dielectric (necessarily dielectric) on the open oscilloscope. Microcracks are difficult to find. Sometimes it's easier to screw everything up.
I do not claim the accuracy of the recommendations. I did not deal with C1-94 so much.
The only thing is, if it has not been used before, but simply stood, or was not used very competently, it may not be calibrated. There should be trimmers for calibration. Look at the side of the case. But this is the second. First - treat the sweep. Maybe a horizontal deflection amplifier, maybe a saw generator. You can try to check the amplifier by applying any signal to the UGO input. I don't remember if this donkey has an external scan. You can apply there if you have.
C1-94 is a good donkey. I liked working with him. Usually reliable. Yes, and check the EPS of the conders. Old Soviet conders are often junk and dry. Weakness.

Added (25.12.2015, 17:24)
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I will add. Because you write that you have not dealt with before. A fixed dot on the screen for no longer than a few seconds. And remove the brightness for now and defocus the beam while you are looking for a malfunction. The phosphor at a fixed point burns out very quickly. Do not solder the socket of the CRT worn on the CRT. A microcrack in the glass from a temperature difference and that's it.

Added (25.12.2015, 18:33)
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I already forgot the basics of verification. Check the power supply of 100 and 200 volts for the UVO and UGO. There may be a malfunction somewhere there. If yours is assembled according to the scheme from the Crab, then there are two conders, a resistor and a bridge. Maybe one electrolyte is dry. Or a crack. Wires. Trance.

Not to mention the money, this oscilloscope is worth fighting for.

Stopped beam drift. After standard balancing according to the manual, the result is enough for about 20 minutes at most. It is especially fun when you need to look at two signals.rather, one and the same, only at the entrance and exit. with amplitudes different by an order of magnitude. when setting up, in a bunch of wires. there is no short circuit button for the probes. and put it nowhere. input divider from 0.01 to 1 and back, like clockwork. In general, the Internet is a great thing, especially when you know what to look for. Just did your way, Borodach, by back-gluing T1 and T2, and lengthening the legs. It's been standing for an hour now, it's being tested. It seems that the result really changes the picture by an order of magnitude. I periodically click from 0.5 to 1 - in place. the soul does not rejoice. Respect.

Boasting, I guess. just checked - yes, about half a division (1/10 of a cell). This is over an hour. It used to be half a cell in 15 minutes.

And I want to describe one more moment. It has been chewed many times in different places, and you will not surprise aces with it, but maybe someone who is not very aware of it yet and comes here will come in handy. A little far.

This oscilloscope came to me about a year ago, and until recently it worked the same way as when I first turned it on. Namely: a satisfactory beam thickness,

_________________
Who served in the army, he does not laugh in the circus.

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Partner in crime

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Hello everyone! I fell into the hands of a faulty S1-94 oscilloscope, after a short repair it turned out that the d1005 had burned out in a high-voltage voltage converter, after replacing the URA, a dot appeared on the screen (although there should be a horizontal line !!) I’m losing my head what to dig further! under repair! I have the first oscilloscope! I attach the diagram below.

Grandfather

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horizontal scan does not work .. when you touch the input with your hand, the point should stretch vertically. on small limits
ps IMHO all electrolytes at once fopku. if they are not tantalum..

This post has been edited waha – Mar 6 2011, 05:17 PM

principled oscilloscope circuit C1-94, block diagrams of the oscilloscope, as well as the description and appearance of the measuring device, photo.

Rice. 1. Appearance of the S1-94 oscilloscope.

Universal service oscilloscope C1-94 is designed to study pulse signals; in the amplitude range from 0.01 to 300 V and up to the time range from 0.1 * 10^-6 to 0.5 s and sinusoidal signals with an amplitude of 5 * 10^-3 to 150 V with a frequency of 5 to 107 Hz when checking industrial and change house radio equipment.

The device can be used in repair services for electronic radio equipment at enterprises and at home, as well as for radio amateurs and educational institutions. Oscilloscope S1-94 complies with the requirements of GOST 22261-82, and according to the operating conditions corresponds to group II of GOST 2226І-82.

Operating conditions of the device.

• ambient temperature from 283 to 308 K (from 10 to 35°С);
• relative air humidity up to 80% at a temperature of 298 K (25°С);
• supply voltage (220 ± 22) V or (240 ± 24) V with a frequency of 50 or 60 Hz;

• ambient temperature under extreme conditions from 223 to 323 K (from minus 50 to plus 50°С);
• relative air humidity up to 95% at a temperature of 298 K (25°C).

• The working part of the screen 40 X 60 mm (8X10 divisions).
• The width of the beam line is not more than 0.8 mm.
• The deviation coefficient is calibrated and is set in steps from 10 mV / division to 5 V / division according to a series of numbers 1,2,5.
• The error of the calibrated deviation coefficients is not more than ± 5%, with a divisor of 1:10, not more than ± 8%.

KVO beam has the following parameters:

The sweep can operate in both standby and self-oscillating modes and has a range of calibrated sweep factors from 0.1 µs/div to 50 ms/div; divided into 18 fixed subranges according to the series of numbers 1, 2, 5.

The error of the calibrated sweep factors does not exceed ±5% on all ranges, except for the sweep factor of 0.1 µs/div. The error of the calibrated sweep factor OD µs/div does not exceed ± 8%.Moving the beam horizontally sets the start and end of the sweep to the center of the screen.

The horizontal deflection amplifier has the following parameters:

• the deviation coefficient at a frequency of 10 ^ 3 Hz does not exceed 0.5 V / division;
• the unevenness of the amplitude-frequency characteristic of the horizontal deflection amplifier in the frequency range from 20 Hz to 2 * 10^6 Hz is not more than 3 dB.

The device has internal and external synchronization of the sweep.

The internal synchronization of the sweep is carried out:

• sinusoidal voltage range from 2 to 8 divisions in the frequency range from 20 Hz to 10 * 10 ^ 6 Hz;
• sinusoidal voltage range from 0.8 to 8 divisions in the frequency range from 50 Hz to 2 * 10 ^ 6 Hz;
• pulse signals of any polarity with a duration of 0.30 μs or more with an image size of 0.8 to 8 divisions.

External synchronization of the sweep is carried out:

• a sinusoidal signal with a swing of 1 V from peak to peak in the frequency range from 20 Hz to 10 * 10 ^ 6 Hz;
• pulse signals of any polarity with a duration of 0.3 μs or more at an amplitude of 0.5 to 3 V. Synchronization instability is not more than 20 ns.

With a reduced supply voltage and moving the handle - the pulse image device, an increase in synchronization instability up to 100 ns is allowed.

When using external synchronization with pulse signals with an amplitude of 3 to 10 V, it is allowed to induce an external synchronization signal to the CVO amplifier up to 0.4 divisions on the device screen with a minimum deviation coefficient.

The amplitude of the negative sawtooth voltage of the sweep at the socket V is not less than 4.0 V. The device is powered from the AC mains with a voltage of (220 ± 22) or (240 ± 24) V (frequency 50 or 60 Hz).

The device provides its technical characteristics after a self-heating time of 5 minutes. Power consumed by the device from the mains at rated voltage, not more than 32 V • A. The device ensures continuous operation under operating conditions for 8 hours while maintaining its technical characteristics.

The voltage of industrial, radio interference is not more than 80 dB at frequencies from 0.15 to 0.5 MHz, 74 dB at frequencies from 0.5 to 2.5 MHz, 66 dB at frequencies from 2.5 to 30 MHz.

Field strength of radio interference, not more than:

• 60 dB at frequencies from 0.15 to 0.5 MHz;
• 54.dB at frequencies from 0.5 to 2.5 MHz;
• 46 dB at frequencies from 2.5 to 300 MHz.

Time between failures of the device is not less than 6000 hours.

Overall, the dimensions of the oscilloscope are not more than 300 X 190 X X 100 mm (250X180X100 mm excluding protruding parts). The overall dimensions of the packing box when packing 4 oscilloscopes are not more than 900 X 374 X 316 mm. Overall dimensions of the box when packing 1 oscilloscope no more than 441 X 266 X 204 mm.

The mass of the oscilloscope is not more than 3.5 kg. The weight of the 1st oscilloscope in the packing box is not more than 7 kg. The weight of 4 oscilloscopes in a packing box is not more than 30 kg.

Rice. 2. Structural diagram of the S1-94 oscilloscope.

The device is made in a desktop version of a vertical construction (Fig. 3). The supporting frame is made on the basis of aluminum alloys and consists of a cast front panel 7 and a rear wall 20 and two stamped strips: the top 5 and the bottom 12. The U-shaped casing and the bottom restrict access to the inside of the device.

There are ventilation holes on the surface of the casing.

For the convenience of working with the device and moving it over short distances, a stand 8 is provided.

The device is made in the original frame with overall dimensions of 100 X 180 X 250 mm.

The oscilloscope consists of the following devices:

• corps,
• EDG,
• sweep,
• amplifier (90 X 120 'mm),
• amplifier (80 X 100 mm),
• power transformer.

The CRT screen and instrument controls are located on the front panel.

Rice. 3. Device design:

1 - bracket; 2 - cover; 3 - development; 4 - screen; 5 - top bar; 6 - screw; 7 - front panel; 8 - stand; 9 - front leg; 10 - amplifier; 11 - delay line; 12 - bottom bar; 13 - back leg; 14 - power cord; 15 - power transformer; 16 - amplifier; 17 - CRT panel; 18 - screw; 19 - cover; 20 - rear wall.

Checking the modes given in table.1 (unless otherwise stated) is produced relative to the body of the device under the following conditions:

• amplifiers U1 and U2: produced with a balanced amplifier; the UZ-V1-4 switch is set to the WAITING position; resistors R2 and R20 beam is set in the center of the screen;
• UZ sweep: resistor R8 (LEVEL) sets the base potential of the UZ-T8 transistor to O; switches UZ-V1-2, UZ-V1-Z, UZ-V1-4 are set to the positions INSIDE, JL, WAITING, respectively, with resistor R20 the beam is set in the center of the screen; the V/DIV and TIME/DIV switches are in positions „05” and „2” respectively; the voltage on the electrodes of the UZ-T7 transistor is removed in the position * of the V / DIV switch; voltages on the electrodes of transistors UZ-T4, UZ-T6 are checked relative to the common point of the diodes UZ-D2 and UZ-D3, while the switch UZ-V1-4 is set to the AVT position; supply voltages of 12 and minus 12 V must be set with an accuracy of ± 0.1 V, with a mains voltage of 220 ± 4 V.

Checking the modes listed in Table 2 (except for those specifically indicated) is carried out relative to the body of the device. Checking the mode on contacts 1, 14 of the CRT (L2) is carried out relative to the cathode potential (minus 2000 V). Operating modes may differ from those indicated in Table. 1, 2 by ±20%.

Winding data of the transformer Tr1 (SHL x 25).

Winding data of the UZ-Tr1 transformer.

Rice. 1. Plan for the placement of elements on the PU of the U1 amplifier.

Rice. 2. Plan for the placement of elements on the PU (amplifier U2).

The plan for placing elements on the launcher is U3 scan.

The layout of the elements on the rear panel of the oscilloscope.

The layout of the elements on the front panel of the oscilloscope.

S1-94 oscilloscope electrical circuit diagram. Amplifier and high-voltage power supply of the S1-94 oscilloscope.

Sweep and low-voltage power supply of the S1-94 oscilloscope.

Many specialists, and especially radio amateurs, are well aware of the S1-94 oscilloscope. The device, with its rather good technical characteristics, has very small dimensions and weight, as well as a relatively low cost. Thanks to this, the model immediately gained popularity among specialists involved in mobile repair of various electronic equipment, which does not require a very wide bandwidth of input signals and the presence of two channels for simultaneous measurements. Currently, a fairly large number of such oscilloscopes are in operation.

In this regard, this article is intended for specialists who need to repair and configure the S1-94 oscilloscope.

Zakharychev E.V., design engineer

View online repair and configuration documentation oscilloscope S1-94

Download | Download : Oscilloscope С1-94

Otherwise, I really face a choice - or stir up a home-made one using DVM (

), plus upgrade the existing C1-94, or spit on everything and save up for tech.

PS. I apologize for the spelling in the topic - the radio keyboard and batteries are running low

You will save for the rest of your life on Tek

Is the upgrade cool? I ask because I have never seen scheme 94/3 and I cannot independently evaluate the difference. But there is interest: if “everything is very simple” ((c) A. Makarevich), then I would like to do tuning of my “Saga”.

It seems that a threefold increase in the band is not as simple as it seems. This is a completely different circuitry and transistors. Moreover, if transistors are a trifle, then the manufacture of new boards will not be easy at all. Since C1-94 (like SAGA) were not made on MP transistors. but with respect to modern silicon, it is not transistors that limit the CVO band. And in a horizontal sweep, most likely, simply reducing the capacitance in the generator will not be enough. There were no articles in Radio on expanding the band, at least I didn’t come across any. Although there were many improvements to these oscilloscopes. But it was all about the probes and small changes.

I was also somehow interested in the differences between C1-94 / 3 and C1-94 on the Radio forum.No one answered. There are only photographs of the first one on the network. I am sure that the boards will definitely have to be redone. This, of course, will not frighten photo virtuosos and irons. The tube in C1-94/3 is different. scale.

I also really want to look at the diagram. Very.

And then I really stand before a choice

A homemade DSO is also not a cheap thing, only the components will pull on a good used analog oscillator. Taking into account “time is money”, Tek-a may be more expensive; Tek is definitely cooler :-) If you have to go, and not checkers, then there seems to be no choice. I think so.

As a child, I had two oscilloscopes (as I grew professionally) - H-313 and H-3013 (with a multimeter and displaying numbers on the tube screen).
Although, I already forget. Maybe someone will fix it. But the point is different.

So, the first one was up to 1 MHz, and the second one was up to 30 MHz review and up to 25 MHz measurements.
In both, in the deflection amplifiers, there were either KT602 or KT611 transistors. Here, the memory is full of holes.

But the key word is the same!

If in the first they were simply soldered into the board, then in the second they were on radiators and heated up in a terrible way - it was exactly 70 degrees. The printed circuit boards were getinaks, so around the transistors they were almost black. If I disassembled the first one only for the purpose of interest and improvement, then the second one was for repair - the electrolytes dried up with a bang. It's good that the installation of the second was modular, and the repair was not difficult.

The amplifier circuits practically did not differ, except for small things and transistors of the preliminary stages.

So, I think that such a huge, at that time (approximately 1984) for an amateur oscilloscope, the frequency was achieved, precisely, by increasing the current of the deviation amplifier transistors.

In old books on circuitry, there were quite a lot of deflection amplifier circuits for homemade oscilloscopes and with a fairly large bandwidth. So, you can analyze the amplifier circuit and try to increase the bandwidth by replacing the transistors with higher frequencies and increasing the current. Naturally, with the use of radiators.

You can remember about monitors for computers. In them, after all, there are amplifiers with a band of up to 60-80 MHz, and in newer ones up to 150 MHz. Circuitry - it couldn't be easier, a microcircuit and an output stage on a pair of transistors.
By the way, it’s not a problem to buy a microcircuit for a monitor’s video amplifier, but on the Internet you can find a dock for it. As a rule, there is a typical switching scheme in the dock. So, such an option, with the replacement of a native amplifier with a modern microcircuit one, may turn out to be effective.
It remains only to add the sweep frequency range.
What do you think?

And is it necessary? Such gimor with labor costs. for one single oscilloscope?

Tranzyulya is all alive. Only I can’t understand about P217. - 12 is normal. What could be the problem?

Tranzyulya is all alive. Only I can’t understand about P217. - 12 is normal. What could be the problem?

To begin with, determine whether the source of power is insufficient or they are trying to remove too much from it.

Sometimes it takes as much intelligence to take advice as it does to give it.
La Rochefoucauld

Tranzyulya is all alive. Only I can’t understand about P217. - 12 is normal. What could be the problem?

“Reading the pager, thinking a lot.”

If there is no error in the circuit, it seems that the stabilizer is common for +12 and -12 sources (at P217), and the voltages are tied to the case using the 361st T10 transistor. But this is somehow strange, he has no power.

That is, in your case, the voltage is underestimated by the stabilizer, but the binding for the -12 source is set correctly.

I would check the zener diodes D9 and D10. Reference anchor voltages are placed on them.

Sometimes it takes as much intelligence to take advice as it does to give it.
La Rochefoucauld

his strnik begins to crack.

And it does not have standby mode.

Can you set the +/-12V voltage?

If at rated voltage “the line begins to crack”, then the fault is in the high-voltage part. Perhaps that is why someone reduced the output voltage of the stabilizer.

The expression “standby mode does not work” can mean various situations: either the standby mode does not turn on (in any position of the “LEVEL” regulator, the sweep continues to work in continuous mode), or in the standby mode, the sweep is not triggered by sync pulses.

Can you set the +/-12V voltage?

If at rated voltage “the line begins to crack”, then the fault is in the high-voltage part. Perhaps that is why someone reduced the output voltage of the stabilizer.

The expression “standby mode does not work” can mean various situations: either the standby mode does not turn on (in any position of the “LEVEL” regulator, the sweep continues to work in continuous mode), or in the standby mode, the sweep is not triggered by sync pulses.

And how was it lowered without changing the design of the circuit?

Yes, the standby mode does not turn on.

The entire circuit of the device is powered by a single stabilized 24V source. The exception is the output stages of the vertical / horizontal deflection channel amplifiers: they have a separate 200V rectifier. A 24V unipolar stabilizer is powered by capacitor C25 and assembled on transistors T14, T16, T17 in the usual way. The output voltage is set by resistor R37. If the voltage is regulated by resistor R37, but it cannot be increased to 24V, the voltage at C25 should be checked. Must be at least 25V. +/-12V can be ignored for now.

”And how was it underestimated without changing the design of the circuit? ” - resistors R37 and R34.

"Yes, standby mode does not turn on."
So, in normal mode, the scan works?

There is an oscilloscope of the 90s C1-94, he was a good friend, cherished like the apple of his eye, he was always at home. I didn’t turn it on for many years either, probably the shore, not probably - but for sure, I didn’t give it to my ex-wife during the divorce. . Anyway, here's a video on google drive. No calibration stability.
I lost the scheme and documentation when moving, even though my head was in place.

As if the rectangles are interchanged, visually run to the right on a sweep at division 5 and do not respond to the controller level. On the 10-ke - vice versa to the left. On the deuce and below - a mess. Actually, it's like it doesn't exist. It is clear that - read RTFM, but I would like to hear advice before you send it!

There are holes on the side for corr amp and balance, above - corr. sweep I haven't twisted or touched anything.

Last edited by KaV on Mon May 25, 2009 2:26 pm; edited 11 times in total
Posted: Sun Jan 21, 2007 1:06 am

"Tomorrow" stretched out for a week

Repaired everything except the horizontal generator. The trans is not broken, the voltage is normal, but it does not start.
Now spat, replaced all 12 trans in horizontal. I turn it on - there is no generation, well, what are you going to do! Armed with a magnifying glass, removed a thin thread of solder from the leads of one of the just soldered Kt315 - there is a generation!
I took a soldered bunch of trans, rang. All are calling correctly. I inserted an RC generator into the test circuit - everything works! Poltergeist, however

Now I'll try to make a matched cable for other oscillators. Luckily I understood the principle.

I bought a certain device without a name for 150 rubles. A probe with a divider of 1:10.

It only says “10MΩ 12Pf” and nothing more.

I checked it on the calibrator. The signal is heavily distorted, and the built-in screw failed to achieve a meander. obviously it is designed for a 12Pf oscillator capacitance, and I have 40.

At HF, it seems no worse than my own probe, but at low frequencies it distorts the signal greatly. In general, advise how to modify it.

I can take it apart and post pics of the inside if needed.

In short, I adjusted everything. Thank you to the encoder. I replaced the standard conder in the probe 8.2Pf with 2 in series 51Pf and 10Pf (selected experimentally) and adjusted it with a regular trimmer to a beautiful signal. The signal is almost the same as with the native probe, the difference is negligible. the half-bridge generator is also fucked up, so here it is

By the way, if anyone is interested in describing the device (someone recently asked).

In the probe, there is a 9.09M 5% resistor and a conder (standard) 8.2Pf in parallel. In the block that the oscillator is attached to, there are a little more parts. choke on the resistor, cap and rezyuk (I didn’t look at the parameters) and then the trim cap parallel to the oscillator input (the value is not specified).

KaV, thanks, but I apparently put it wrong.

The problem is this:
When synchronizing with the network, there are no problems - I turn the “stability” to the left until the signal stops, although the brightness decreases. (level set to predetermined optimal position)

With other types of synchronization, the signal on the screen does not stop, but immediately goes out (until recently, I thought that the synchronization from the signal and the external one were generally faulty, I have had this oscil for about a year and I had to suffer a lot with stopping the image “duration”), but yesterday I noticed that when turning the “uran”, the signal still appears for a short time. As it turned out, an ultra-precise setting of this regulator is required, it corresponds to the optimal position when synchronizing from the network, but it requires extremely high accuracy in setting the “level” resistor engine, which is not possible to “hit” the first time (but the signal brightness does not decrease, as with a network one) , at frequencies close to 50 Hz, it fails at all, but the signal flashes on the screen when passing this point. The resistor is normal, when synchronizing from the network, the signal is “caught” in a quarter of the scale.

So I thought I'd ask how are you?

Generally Oscil 76g. release and strongly zayuzan, although for this one I had to pay 500 rubles, on the market the dead two-channels were sold for 1000.

Last edited by KaV on Mon Jan 18, 2010 7:06 pm; edited 1 time in total
Posted: Thu Nov 15, 2007 7:27 pm

Since the sync works normally from the network and from an external signal (at first I applied too low voltage to the input of the external sync; it turned out that the required accuracy of setting the “level” depends on the sync voltage), then only the T3 transistor of the U3 block and its circuit remains.

With a signal deployed to the limiting lines, the variable component at KT3 is 6.7V, at KT5 2V, but, as I understand it, the voltage at KT5 should be greater than at KT3.
The voltages supplied to the board are normal.

What is the maximum voltage that can be applied to the “external sync 1:1” input?
Do you have instructions for it?

KaV, thank you very much for your help, otherwise I would not have got into it soon.

During experiments with external synchronization, it turned out that for stable synchronization at point 7, a 1V synchroamplifier is more than enough, and at KT5 2V, after which an open circuit was detected between them with an ohmmeter. Raising the synchronization amplifier board revealed the reason - the wire connecting it to KT5 came off the switch, which was immediately soldered back.

After turning on the donkey, it hit its own synchro: the signal stabilized even at a height of 5 mm, which, in principle, is not surprising, because. with a 2kHz input signal, when the wire was broken, negligible capacitive currents were enough for synchronization. 😮
Indeed, a dual-purpose technique 😮

Connect the topic with “Measuring instruments-> Recommend an oscilloscope”. Well, or at least just transfer it to the “Measuring Instruments” section.

For me, such an oscill serves as a “reserve-exit”, but the main one, after all, is C1-68. Yes, coffin. Yes, 12 kg. Yes, only 1 MHz. But I like it and it's extremely easy to use.

P.S. H313 given to Kirillnow (I hope for good deeds )

Last edited by KaV on Thu Dec 27, 2007 10:23 pm; edited 1 time in total
Posted: Thu Dec 27, 2007 2:01 pm