S1 94 oscilloscope adjustment DIY repair

I bought an oscilloscope C1-94 somehow for carrying out repairs (I have been thinking about buying such a device for a long time), it is not new and got it cheap, though the probe turned out to be homemade there, then I will redo it, but still, since the device was rarely used, I decided to go through it a little and replace it, which did not work and gave jambs. So, I found a diagram, studied a bunch of forum information, guides and several articles. All this took several days, 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 rush at it right away with a soldering iron and in a couple of hours the problem cannot be solved here, you need an approach, knowledge, experience.

Schematic diagram C1-94

In general, to begin with, I'll tell you briefly 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 side is even better.

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

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

There is also a flip-up board that is made this way for ease of installation and repair, and a board covered with a plastic casing at the back, which is fastened with a screw - and it just got worn out to unscrew!

I took off the tube for the convenience of repair - you need to unscrew the clamp by slightly displacing it, as well as the guide clamp, 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 glow for a long time in order to put it in the right, correct position. The wires are flexible, durable, nothing came off during the repair process, everything was done to my conscience - these are not modern delicate Chinese devices, where half of the wiring and part of their fasteners can fall off at the very first dismantling. In particular, there was a poor balancing of voltages of 12-0-12 volts (bipolar), there the imbalance should be negligible, and how I did not regulate it turned out to be about 1 volt.

I began to check the electrolytes, simply by desoldering in turn and measuring the capacity of those who could reach - a couple turned out to be dried out, one new one blew up itself, confusing the polarity of the soldering back - there are very scanty markings on the PCB on the board, and if you solder several elements, you can get lost during installation back ...

When it was possible to set the voltage in the order of the norm, the balance was what was needed, adjusted with 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 is 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 elements of the circuits.

The switches can be cleaned, and their contacts can be wiped with acetone to make them shine and not black. Then, when they switch the operating modes of the device, there will be no jumps and serious distortions.

When reassembling after repair, check the position of the tube and set it straight.I attach to the article all the diagrams and materials that helped me in repairing this wonderful service oscilloscope. Repairs done by redmoon.

Repair and adjustment of the C1-94 oscilloscope

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 engaged in the mobile repair of various electronic equipment, which does not require a very wide input signal bandwidth and the presence of two channels for simultaneous measurements. A fairly large number of such oscilloscopes are currently in operation.

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

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

The KGO includes a sync amplifier, a sync trigger, a trigger circuit, a sweep generator, a blocking circuit, and a sweep amplifier. It is designed to provide a linear deflection of the beam with a given sweep ratio from 0.1 μs / div to 50 ms / div with a step of 1-2-5.

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

The cathode ray indicator assembly consists of a cathode ray tube (CRT), a CRT power supply circuit, and an illumination circuit.

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

Let's consider the operation of an oscilloscope at the level of a schematic diagram.

The signal under investigation is fed through the input connector Ш1 and the push-button switch В1-1 ("Open / Closed input") to the input switchable divider on the elements R3. R6, R11, C2, C4. C8. The input divider circuit provides a constant input impedance regardless of the position of the vertical sensitivity switch B1 ("V / DIV"). The divider capacitors provide frequency compensation for the divider across the entire frequency band.

The signal under study from the KVO preamplifier circuit through the emitter follower stage on the T6-U1 transistor and the B1.2 switch is also fed to the input of the KGO synchronization amplifier for synchronous triggering of the sweep circuit.

The synchronization channel (ultrasonic unit) is designed to start the scan 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-US transistor, a differential amplification stage on T9-US, T12-US transistors, and a synchronization trigger on T15-US, T18-US 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. In the differential stage, the polarity of the synchronizing signal is switched (B1-3) and amplified to a value sufficient for triggering the synchronization trigger. From the output of the differential amplifier, the sync 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 C28-UZ, Ya56-U3 differentiating chain, controls the operation of the trigger circuit.

To increase the stability of synchronization, the synchronization amplifier, together with the synchronization trigger, is powered by a separate 5 V voltage regulator on the 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 varying sawtooth voltage in the standby and self-oscillating modes.

As a sweep generator, a timing capacitor discharge circuit through a current stabilizer was selected. The amplitude of the linearly varying sawtooth voltage generated by the sweep generator is approximately 7 V. The timing capacitor C32-UZ during recovery is quickly 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 starting circuit, disconnecting the timing capacitor circuit from the starting circuit. The capacitor is discharged through the T29-UZ transistor, connected according to the current stabilizer circuit. The discharge rate of the timing capacitor (and, consequently, the value of the sweep factor) is determined by the magnitude of the current of the T29-UZ transistor and changes when the timing 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. Changing the sweep factor 1000 times is ensured by switching the timing capacitors C32-UZ, C35-UZ using the Bl-5 ("mS / mS") switch.

Table 1. DIRECT CURRENT ACTIVE ELEMENT MODES

Added by (25.12.2015, 15:32)
———————————————
After a couple of turns on, a luminous dot appeared on the screen and that's it. Up, down, on the sides it is "possible" to move it. Brightness control works.

Where can you find such a diode? I mean the old USSR technology.
There is a suspicion that the “post office” dropped the package with the device, as the box was slightly dented on one side. Perhaps that is why this malfunction appeared.

There is no sweep.
According to the totality of signs, there may be a lack of penetration or a microcrack. Look at the board with a magnifying glass, solder anything suspicious. Try using an open, switched on oscilloscope to lightly push on the boards with something dielectric (always dielectric). It is difficult to find microcracks. Sometimes it's easier to solder everything stupidly.
I do not claim the accuracy of the recommendations. I didn’t deal with C1-94 so much.
The only thing is, if it has not been used before, but just stood, or was not used too 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 scan. Possibly a horizontal deflection amplifier, possibly a saw generator. You can try to test the amplifier by applying any signal to the input of the UGO. I don't remember if this donkey has an external scan. You can apply there, if you have one.
C1-94 is not a bad donkey. I enjoyed working with him. Usually reliable. Yes, and check the EPS of the conductors. Old Soviet Conders are often junk and dry out. Weakness.

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

Added by (25.12.2015, 18:33)
———————————————
I have already forgotten the basics of checking. Check the power supply of 100 and 200 volts for VDU and UGO. There may be a malfunction somewhere there. If yours is assembled according to the scheme from the Crab, then there are two conductors, a resistor and a bridge. Perhaps one electrolyte is dry. Or a crack. Wires. Trance.

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

Pulled up the drift of the beam. After standard balancing according to the manual, the result is enough for about 20 minutes.It is especially fun when you have to watch two signals. or rather, one and the same, only at the entrance and exit. with amplitudes that are an order of magnitude different. when setting up, in a heap of wires. there is no short circuit button for the probes. and there is nowhere to put it. input divider from 0.01 to 1 and back, like a clockwork. All in all, the internet is a great thing, especially when you know what to look for. I just did it your way, Borodach, by gluing backs T1 and T2, and lengthening the legs. It's already been an hour, it's being tested. It seems that the result really changes the picture by an order of magnitude. periodically click from 0.5 to 1 - in place. the soul will not be overjoyed. Respect.

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

And I also want to describe one moment. He's been chewed many times in different places, and you won't surprise the aces with him, but maybe someone who is not yet very in the know will come here - it will come in handy. A bit from afar.

I got this oscilloscope about a year ago, and until recently it worked as it did when I first turned it on. Namely: satisfactory beam thickness,

_________________
Those who served in the army do not laugh in the circus.

Attention!

Attention! Before creating a topic on the forum, use the search! A user who created a theme that has already been will be banned immediately! Read the rules for naming topics. Users who created a topic with incomprehensible titles, for example: "Help, Scheme, Resistor, Help, etc." will also be locked forever. A user who created a topic not in the forum section will be immediately banned! Respect the forum and you will also be respected!

Partner in crime

Group: Participant
Posts: 1390
User #: 11178
Registration: 8-September 06
Place of residence: Europe.

Hello everyone! I got my hands on a faulty C1-94 oscilloscope, after a short repair it turned out that d1005 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 wonder what to dig further! under repair! I have the first oscilloscope! I attach the diagram below.

Grandfather

Group: Participant
Messages: 5277
User #: 34556
Registration: 3-July 08
Place of residence: you have to get out of here.

horizontal sweep does not work .. when the hand touches the entrance, the point should extend vertically. at small limits.
zs IMHO all electrolytes at once ftopku. if they are not tantalum ..

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

Principled S1-94 oscilloscope circuit, oscilloscope block diagrams, as well as description and appearance of the measuring device, photo.

Rice. 1. External view of the S1-94 oscilloscope.

The 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 from 5 * 10 ^ -3 to 150 V with a frequency from 5 to 107 Hz when checking industrial and household radio equipment.

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

Operating conditions of the device.

• ambient temperature from 283 to 308 K (from 10 to 35 ° C);
• relative air humidity up to 80% at a temperature of 298 K (25 ° C);
• 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 ° C);
• relative air humidity up to 95% at a temperature of 298 K (25 ° C).

• The working part of the screen is 40 X 60 mm (8X10 divisions).
• The beam line width is no more than 0.8 mm.
• The coefficient of deviation is calibrated and set in steps from 10 mV / division to 5 V / division according to the series of numbers 1,2,5.
• The error of the calibrated coefficients of deviation is no more than ± 5%, with a divider of 1:10 no more than ± 8%.

The KVO of the beam has the following parameters:

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

The error of the calibrated sweep coefficients does not exceed ± 5% on all ranges, except for the sweep coefficient of 0.1 μs / division. The error of the calibrated sweep coefficient OD μs / division does not exceed ± 8%. Moving the beam horizontally sets the start and end of the sweep in 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;
• non-uniformity of the amplitude-frequency characteristics of the horizontal deflection amplifier in the frequency range from 20 Hz to 2 * 10 ^ 6 Hz no more than 3 dB.

The device has internal and external synchronization of the sweep.

Internal synchronization of the sweep is carried out:

• sinusoidal voltage swing from 2 to 8 divisions in the frequency range from 20 Hz to 10 * 10 ^ 6 Hz;
• sinusoidal voltage swing 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 with an amplitude of 0.5 to 3 V. Synchronization instability is not more than 20 ns.

With a reduced voltage of the supply network and moving the handle - the pulse imaging device, an increase in the 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 send an external synchronization signal to the KVO amplifier up to 0.4 divisions across the device screen with a minimum deviation coefficient.

The amplitude of the negative ramp voltage at the V socket is not less than 4.0 V. The device is powered from an alternating current network with a voltage of (220 ± 22) or (240 ± 24) V (50 or 60 Hz).

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

Industrial voltage, radio interference no 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.

The strength of the radio interference field is 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.

MTBF of the device is not less than 6000 hours.

Overall dimensions of the oscilloscope no 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 no more than 900 X 374 X 316 mm. The overall dimensions of the box when packed by 1 oscilloscope are not more than 441 X 266 X 204 mm.

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

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

The device is made in a desktop version of 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: upper 5 and lower 12. The U-shaped casing and the bottom limit 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 an original frame with dimensions of 100 X 180 X 250 mm.

The oscilloscope consists of the following devices:

• housing,
• 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 - scan; 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 - back wall.

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

• amplifiers U1 and U2: produced with a balanced amplifier; the UZ-V1-4 switch is set to the WAITING position; with resistors R2 and R20, the beam is installed in the center of the screen;
• ultrasound sweep: with a resistor R8 (LEVEL), the base potential of the UZ-T8 transistor is set to O; switches UZ-V1-2, UZ-V1-Z, UZ-V1-4 are set to the positions INUTR, JL, WAITING, respectively, with the resistor R20 the beam is set in the center of the screen; switches V / DIV and TIME / DIV are in positions "05" and "2", respectively; the voltage at the electrodes of the UZ-T7 transistor is removed in the position * of the V / DIV switch; the voltage ua of the electrodes of the UZ-T4, UZ-T6 transistors are checked against the common point of the UZ-D2 and UZ-D3 diodes, while the UZ-V1-4 switch is set to the AVT position; supply voltages 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 shown in Table 2 (except for those specifically mentioned) is carried out with respect to the device body. Checking the mode on contacts 1, 14 of the CRT (L2) is carried out, relative to the potential of the cathode (minus 2000 V). The modes of operation may differ from those indicated in the table. 1, 2 by ± 20%.

Transformer winding data Tr1 (ШЛ х 25).

Data of the winding of the UZ-Tr1 transformer.

Rice. 1. Layout of elements on the PU amplifier U1.

Rice. 2. Layout of elements on the PU (amplifier U2).

Layout plan of elements on the PU - sweep U3.

Layout of items on the rear of the oscilloscope.

Layout plan for the front panel of the oscilloscope.

S1-94 oscilloscope electrical schematic diagram. S1-94 oscilloscope amplifier and high-voltage power supply.

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 engaged in the mobile repair of various electronic equipment, which does not require a very wide input signal bandwidth and the presence of two channels for simultaneous measurements. A fairly large number of such oscilloscopes are currently in operation.

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

Zakharychev E.V., design engineer

View online repair and customization documentation oscilloscope S1-94

Download | Download: Oscilloscope S1-94

And then I really face a choice - or stir up a homemade one with the help of DVM (

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

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

You will save for Tek for the rest of your life

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

It seems that increasing the band by three times is not as easy as it seems. This is a completely different circuitry and transistors. Moreover, if transistors are a trifle, then making 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 the transistors that limit the KVO band.And in a horizontal sweep, it is likely that simply reducing the capacitance in the generator will not be enough. Something in the Radio on expanding the band there were no articles, at least I did not come across. Although there were many improvements to these oscilloscopes. But it was all about the probes and minor changes.

On the Radio forum, I was also somehow interested in the differences between C1-94 / 3 and C1-94. No one answered. The network has only photos of the first. I am sure that the boards will have to be redone for sure. This of course will not frighten the virtuosos of the photo and the iron. The pipe in C1-94 / 3 is different. In appearance and dimensions, it looks like 8LO6I with no parallax scale.

I also really want to see the diagram.

Otherwise I really face 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 come out more expensive; Tek is definitely cooler: -) If you need to go, and not checkers, then there is no choice. I think so.

In my childhood I had two oscilloscopes (as my professional growth) - N-313 and N-3013 (with a multimeter and displaying numbers on the screen of the tube).
Although, I already forget. Maybe someone will fix it. But the point is different.

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

But the key words are the same!

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

The amplifier circuits were practically the same, except for the little things and the transistors of the preliminary stages.

So, I think that such a huge, at that time (about 1984) for an amateur oscilloscope, the frequency was achieved, namely, by increasing the current of the transistors of the deflection amplifiers.

In the old books on circuitry, there were quite a few deflection amplifier circuits for homemade oscilloscopes and with a rather large bandwidth. So, you can analyze the amplifier circuit and try to increase the bandwidth by replacing the transistors with higher frequency ones 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 bandwidth of up to 60-80 MHz, and in newer ones up to 150 MHz. Circuitry - it couldn't be simpler, 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 video amplifier, but on the internet you can find a dock for it. As a rule, there is a typical connection diagram in the dock. So, such an option, with the replacement of the native amplifier with a modern microcircuit, may be effective.
All that remains is to add the sweep frequency range.
What do you think?

Do you need it? Such a gimor with labor costs. for one single oscilloscope?

All are alive, but I can't understand about P217. - 12 is normal. What could be the problem?

All are alive, but I can't understand about P217. - 12 is normal. What could be the problem?

To begin with, determine whether the source of power is not enough or they are trying to remove it from it.

Sometimes, to take advice, you need to be as smart as to give it.
La Rochefoucauld

All are alive, but I can't understand about P217. - 12 is normal. What could be the problem?

"I read the pager, I thought a lot."

If there is no error in the circuit, it seems that the stabilizer is common for the +12 and -12 sources (on P217), and the voltages are tied to the case using the 361st transistor T10. 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. The reference stresses of the snapping are made on them.

Sometimes, to take advice, you need to be as smart as to give it.
La Rochefoucauld

his scribe begins to crackle.

And the standby mode does not work for him.

Can you install the +/- 12V voltage?

If at the rated voltage, "the stringer starts to crack," then there is a fault 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 different situations: either standby mode does not turn on (in any position of the LEVEL knob, the sweep continues to work in continuous mode), or in standby mode, the sweep is not triggered by sync pulses.

Can you install the +/- 12V voltage?

If at the rated voltage, "the stringer starts to crack," then there is a fault 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 different situations: either standby mode does not turn on (in any position of the LEVEL knob, the sweep continues to work in continuous mode), or in standby mode, the sweep is not triggered by sync pulses.

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

Yes, standby does not turn on.

The entire circuit of the device is powered from one stabilized 24V source. An exception is the output stages of amplifiers of vertical / horizontal deflection channels: for them there is a separate 200V rectifier. The unipolar 24V regulator is powered by a capacitor C25 and is assembled on transistors T14, T16, T17 in the usual way. The value of the output voltage is set by the resistor R37. If the voltage is regulated by the resistor R37, but it is not possible to increase it to 24V, the voltage at C25 should be checked. Must be at least 25V. You can ignore +/- 12V for now.

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

"Yes, standby does not turn on."
Does it mean that the scan works in normal mode?

There is an oscilloscope S1-94 of the 90s, he was a good friend, the shore was like the apple of his eye, he was always at home. I didn’t include it for many years either, the shore probably, not for sure - but for sure, I didn’t give it to my ex-wife during the divorce. ... In general, here's a video on google drive. No calibration stability.
I lost the diagram and documentation when moving, even though my head was in place.

As if the rectangles are swapped, visually run to the right on the sweep at division 5 and does not respond to the regulator level... On 10-ke - vice versa to the left. On a deuce and below - a mess. In general, as if it does not 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 usit and balance, above - corr. sweep - did not twist anything and never 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” lasted for a week

I fixed everything, except for the horizontal generator. Transitions are not broken, the spill is normal, but it does not start.
Now he spat, replaced all 12 tranzes in a horizontal line. I turn it on - there is no generation, 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 generation!
I took a pile of trances that had been soldered and rang. Everyone calls correctly. I inserted an RC generator into the test circuit - everyone works! Poltergeist, however

Now I will try to make a matched cable for other oscillators. Fortunately, I understood the principle.

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

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

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

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

If necessary, I will disassemble and throw pictures of the insides.

In short, I adjusted everything. Thanks to the encoder. I replaced the standard condenser in the 8.2Pf probe by 2 sequentially 51Pf and 10Pf (I selected it experimentally) and adjusted it with a standard 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 fucking awesome, so here it is

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

In the probe, a 9.09M resistor of 5% and a conductor (standard) 8.2PF in parallel. In the block that attaches to the oscillator a little more parts. A 220 Ohm variable resistor in parallel to the probe (between the central core and the screen), then an antiparasitic chain of a seemingly unbalanced purpose from series-connected a choke on a resistor, a cap and a resistor (I did not look at the parameters) and then a trimmer cap parallel to the input of the oscillator (the nominal value is not specified).

KaV, thanks, but I probably 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. (the level is set at a predetermined optimum 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 oscillator for about a year now and I had to suffer a lot with freezing the image), but yesterday noticed that when the “uroan” is turned, 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 requires an extremely high accuracy of setting the "uroan" resistor slider, which is far from being "hit" the first time (but the signal brightness does not decrease, as with the network) , at frequencies close to 50 Hz it does not work at all, but the signal flashes on the screen when passing this point. The resistor is normal; when synchronized from the mains, the signal is "caught" in a quarter of the scale.

So I decided to ask how you are

In general, the oscillator is 76g. release and heavily used, although it was necessary to pay 500 rubles for this, on the market the killed two-channel units were sold for 1000.

Last edited by KaV (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 a voltage to the input of the external sync; it turned out that the required accuracy of setting the “level” depends on the synchronization voltage), then only the transistor T3 of the U3 block and its circuit remains.

When the signal is 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 more than at KT3.
The voltage supplied to the board is 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 get into it soon.

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

After switching on, the master was struck by the synchro: the signal stabilized even at a height of 5mm, which, in principle, is not surprising, tk. at 2 kHz of the input signal with a wire break for synchronization, it had enough negligible capacitive currents. 😮
Indeed, a dual-use technique 😮

Would connect the topic with “Measuring Instruments-> Advise Oscilloscope”. Well, or at least just transfer it to the "Measuring Instruments" section.

For me, such an oscillator serves as a "spare-exit", but the main one, after all, is C1-68. Yes, the coffin. Yes, 12 kg. Yes, only 1 MHz. But I like it and it is extremely convenient to use.

P.S. Н313 is given to Kirillnow (I hope for good deeds )

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