8 mm video cameras. Distinctive features of formats, LPM device, repair. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Телевидение

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Equipment for recording and reproducing video and audio signals using 8 mm wide magnetic tape has become quite widespread in the world, including in our country. Existing such formats, their differences and available video camera models are described in this article. It also examines the designs of used CVLs and, using the SAMSUNG model as an example, provides recommendations for its disassembly and repair.

This year marks 20 years since the release in 1983 by SONY of the first models of video recorders (VM) and video cameras (VC) working with magnetic tape 8 mm wide. Despite the active transition to digital technologies when recording image and sound signals on magnetic, optical media and even solid-state (semiconductor) devices, large quantities of analog video recording equipment, including VK 8 mm formats, continue to be produced. The fleet of this equipment, including in Russia, is very significant. However, a large percentage of it consists of devices that have already reached the end of their service life and require repair or maintenance.

To successfully carry out service activities with them, technical literature, operational documentation, spare parts, special equipment and measuring equipment are required. Unfortunately, information on 8 mm formats is available to us mainly in the most general form. It is completely insufficient for the repair and maintenance of specific equipment, and it is difficult to use information on VHS (S-VHS) models for such a purpose due to many significant differences in circuitry and design features. Therefore, it is necessary to talk in more detail about the device and service of 8 mm VK formats, about their differences from equipment of other formats.

Calling the new format VIDEO-8 (V8 for short), SONY in 1988 began producing high-quality equipment called HI-8 (HI8). Since then, the V8/HI8 VC has been continuously improved. Other well-known companies also joined their production: HITACHI, CANON, SHARP, SAMSUNG, SANYO and a number of companies (GRUNDIG, MINOLTA, NOKIA, PENTAX, OLIMPUS, RICON, etc.), purchasing equipment from the above listed. Most of the improvements concerned the consumer characteristics of VK (operating modes, special effects, titles, image stabilization, etc.).

However, at the end of the 90s, SONY significantly improved the main technical parameters of the VK. First of all, this relates to the horizontal resolution of the image. The technology that allows you to increase resolution is called XR-Extended Resolution. Therefore, the formats received this prefix name: VIDEO-8XR/HI-8XR. Moreover, their compatibility with conventional V8/HI8 equipment has been preserved. The achieved increase in resolution compared to 250 and 400 lines of conventional V8/HI8 VCs, respectively, amounted to 8 lines in the best V300XR VC models, and 8 lines horizontally in the HI450XR VC. It should be especially emphasized that in such VCs, image clarity largely depends on the characteristics of the light/signal converter and, first of all, on the number of active pixels of the CCD matrix and its dimensions (measured in inches).

As an example, we list information about the number of pixels for the SONY VK model range from the catalog [1].

HI8XR format: CCD-TR3200 - 440000, CCD-TR840/845 - 520000, CCD-TRV300 - 440000, CCD-TRV99/89 - 360000; V8XR format: CCD-TR730 - 360000, CCD-TR640 - 520000, CCD-TR512/511 - 290000, CCD-TR412/411 - 290000.

It is noteworthy that the CCD-TRV99/89 (HI8XR) and CCD-TR730 (V8XR) VCs use CCD matrices with the same number of pixels, while the CCD-TR640 model has a CCD matrix with a number too large for recording in V8 format pixels. This must be remembered when purchasing a VK, since in terms of image quality when playing back a recorded recording, some models of the V8XR and HI8XR formats are equivalent (of course, only in terms of clarity).

Let's briefly look at some of the most significant innovations applied in VK formats V8(XR)/HI8(XR). The NIGHT SHOT function - shooting in complete darkness (SONY 1998) - is implemented by turning off the optical filter that suppresses IR rays and illuminating objects with an IR radiation source built into the VC. At the same time, you can shoot scenes in black and white at a distance of up to 5...6 m. New HYPERMIG video heads in combination with XR technology make it possible to improve the signal-to-noise ratio by 30% for the luminance signal and by 10% for the color signal. STAMINA technology (SONY 1998) - optimization of energy consumption - ensures continuous operation of up to 12 hours from a single charge of lithium ion batteries. "Intelligent" batteries INFO LITHIUM (SONY, 1998) inform about the possible operating time with an accuracy of 1 minute. STEADYSHOT and SUPERSTEADYSHOT (SONY) systems guarantee maximum image shake compensation using an optical prism or a special 8000000 pixel CCD matrix. The LASER LINK system is used for remote transmission (up to 10 m) of image and sound signals using IR rays. The SONY IFT-R10 IR receiver connected to the TV is usually supplied additionally (for an additional fee). Digital special effects were obtained during recording: freeze frame, strobing, stretching/compression, etc.

In the spring of 1999, SONY began selling VK in the new digital format DIGITAL-8 (D8). And this despite the fact that by that time most manufacturers were focusing on a single digital format for household recording, MINI DV, including SONY itself, which produced a whole line of such models. The potential of the D8 format is very high: digital recording is provided on serial HI8 video cassettes, and they are almost three times cheaper than MINI DV cassettes, VK allows you to play back recordings in V8/HI8 formats, prices for D8 models are lower than MINI DV cameras. These three factors can significantly extend the life of 8mm video recording equipment.

By the end of 2000, 10 models of digital VC D8 from SONY and about 40 models of MINI DV from CANON, JVC, PANASONIC, SONY, SHARP, THOMSON were presented on the Russian market. Prices for VK D8 range from $800 to $1400 (the cheapest is SONY - DCR-TRV120), and VK MINI DV prices range from $950 to $3000 (the cheapest is PANASONIC - NV-DS11EN). In the same year, the new format was supported by HITACHI, releasing two VK D8 models: VMD-865LA and VMD-965LA.

Let's consider the technical features and characteristics of the D8 VC in comparison with models of the V8/HI8 formats, information about which is given in [2, 3]. In the VK D8, the rotation speed of the BVG is tripled - 4500 rpm. The tape drawing speed also increased to 28,7 mm/s. In VK V8 (PAL, SP) it is equal to 20,05 mm/s. This is due to the not very high characteristics of HI8 magnetic tapes. Increasing their transfer speed naturally led to a decrease in recording time: a two-hour HI8 cassette lasts 1 hour 20 minutes, and a one-hour tape lasts 40 minutes. Unfortunately, increased head/tape speed reduces the service life of video heads.

With increasing speeds, the signalgram also changed. In the D8 format, each frame is recorded on six (PAL) or five (NTSC) slanted lines, each of which is recorded by two video heads (they switch in the middle of the tape). In addition, due to the reduction in the width of the recording tracks, it was necessary to reduce the length of the video head gaps to approximately 16 microns. In V8 format, the recording track width is 34,4 (PAL) or 20,5 (NTSC) microns.

500 lines horizontally - this is the resolution of the D8 format. In addition, the new VCs are equipped with a digital I.LINK device with access to a data bus operating according to the international IEEE1394 standard at transmission speeds from 100 to 400 Mb/s. Through the I.LINK device, it is possible to “digitize” recordings in V8/HI8 formats, and in some models, external signals. Communication with a computer can also be provided through a special miniature MEMORY STICK memory card with a capacity of up to 8 MB, and in the future up to 128 MB. All second generation SONY VKs (2000-2001 release) have a special card slot. There are models that are equipped with a built-in color printer for printing 5x9 cm photo frames from buffer memory or flash memory inserted into the same MEMORY STICK slot (SONY model - DCR-TRV820).

Issues regarding service and repair of models of new generations of 8 mm equipment will not arise soon. Therefore, we will consider the features of the circuit design, design and operation of the most common V8 VCs in our country. Their fundamental differences from VHS/VHS-C concern only the VCR sections. Camera heads, control systems, electric drives, power supplies, network adapters and some other components do not have such differences (only circuit design). But the VCR sections in the VK of the formats under consideration differ significantly both in the construction of auto-regulation systems (AVR), image and sound channels, and in the designs of the CVL.

We will indicate the most significant differences between VK V8 (“eights”) and VHS equipment. In the drive shaft ACS, the figure-of-eight phase channel is based on the use of auto-tracking signals (ATF), recorded and played back by rotating video heads. In general, the concept of “tracking” is absent for users of these VKs (there are no such regulators), as well as problems with playing recordings made on different VKs. Analog video and audio (FM) signals are recorded and reproduced by the same heads. However, it is possible to record audio signals using PCM. Most VK models do not have audio channels that use fixed universal and erase heads. Consequently, in the V8 CVL there are practically no fixed heads, although the VXNUMX format itself provides longitudinal tracks for sound and control signals, but in VK they are, as a rule, not used.

A significant number of VK malfunctions occur due to wear and breakdown of the mechanical components of the CVL. Often failures of VK electronic components occur when the cassette is loaded, further removal of which is impossible without disassembling the mechanism. Therefore, for effective repairs, a clear understanding of the structure of CVLs and the ability to develop/assemble them is necessary.

Since the release of the first 8 mm format VCs, many types of CVLs have been developed, most of which are based on technical solutions and patents from SONY. Most often, CVLs have a shaft cassette loading system. However, V8/HI8 editing machines use front loading, just like VHS machines. Such VMs include the SONY device - EV-C3E, produced in 1989-1992. It has a CVL with four motors that provide BVG and explosive drive, cassette and tape refilling.

This network device, measuring 178x88x255 mm and weighing 2,2 kg, in addition to the usual functions, allows you to edit video materials synchronously with the SONY VK, equipped with a special LANK CONTROL interface (five-pin CONTROL-L connector). The BVG with three magnetic heads, used in this VM, is used in many SONY VC models produced in the early 90s with a U-type CVL (U mechanism). Its device is presented in the manual [4], available for sale on radio markets.

The cassette receiver of the U shaft type mechanism is rigidly fixed on a stamped base. The approximate dimensions of the CVL with an installed video cassette are 120x105x40 mm.

In order to reduce the dimensions of the VK, the CVLs have undergone significant changes. In particular, cassette receivers began to be made in the form of retractable structures, which made it possible to reduce them to dimensions of 90x105x35 mm. This is how the CVL (mechanism B) was made for more than four dozen SONY VK models produced in 1997-1999. Mechanism B is strictly unified. It is used both in the expensive HI8 VC (for example, CCD-TR3100E, $1250) and in the relatively cheap VIDE08 VC (CCD-TR420E, $440). The CVLs of different VCs of this series differ only in the type of installed BVG. The line includes the following SONY VCs: CCD-TR330/340/401/402/420/440/510/520/3100/3400; CCD-TRV10/11/ 12/14/21 /22/24/31 /32/34/44/51 /52/53 /54/56/61 /62/64/72/81 /82/91 /94/ 112/212/312/512 and some others. .

To order spare parts when carrying out repairs, you must know the part numbers according to the specifications of mechanism B (8 mm MECHANISM DECK, SONY B-MECHANISM). They can be found in the manual [5], sold on radio markets.

The retractable design of the cassette receiver is also used in a number of SAMSUNG models. We will consider the device of the CVL, the features of its disassembly and repair using the example of SAMSUNG video cameras - VP-U12/U15. Its design is demonstrated in Fig. 1 and 2.

Numbers in Fig. 1 is marked: 1 and 2 - terminals of the refueling motor; 3 - BVG; 4 - driving engine; 5 - winding gear; 6 - cassette receiver; 7 - pressure roller; 8 - right guide unit; 9 - left guide unit; 10 - program switch; 11 - program gear; 12 - refueling engine.

In Fig. The connectors are marked with 2 numbers: 1 - refueling motor; 2 - lower part of the CVL; 3 - rotating transformer BVG; 4 - BVG engine; 5 - explosive engine; 6 - cassette receiver.

In Fig. Figure 3 shows a bottom view of the V8 cassette. It is marked with numbers: 1 - inner cover; 2 - hole for the central LED; 3 - outer cover; 4 - cover lock; 5 - holes for fixing the cassette; 6 - identification holes.

Of practical interest is the method of disassembling faulty CVLs, i.e. those that do not show signs of life, a VK with a refilled cassette. To remove it, remove the cassette cover (unscrew two screws), the plastic o-ring (located immediately behind the lens, unscrew one screw from the bottom), the microphone assembly (four screws) and the right side cover (two C3adi screws, four screws from the bottom). This opens access to the CVL from above. For forced ejection of the cassette, a constant voltage of 4...6 V is applied to the terminals of the refueling motor 12 (see Fig. 1), having previously disconnected connector 1 (see Fig. 2): the negative wire from the power source is connected to terminal 1 (see Fig. Fig. 1), and the positive one - to pin 2, connecting any button to any of these circuits.

The operation must be carried out in small steps by pressing this button. The first stop is made when the cassette receiver 6, moving out, frees access to the rewind gear 5. By turning this gear counterclockwise with a thin screwdriver, the tape loop is removed inside the video cassette. Apply power again with the button until the cassette tray rises up and the cassette can be removed.

Repair of the CVL must be carried out using, if possible, the service instructions (SERVICE MANUAL). In this case, an experienced repairman can disassemble the mechanism himself. However, it is necessary to record the order of disassembly operations, the type of fasteners, and also sketch the characteristic configurations of the mechanism parts and their relative positions. This will allow you to reassemble the camera without any problems.

If you need to purchase or order mechanism parts and specialized electronic components from branded service centers, you need to know the names of the parts and their numbers (PART NO).

To repair the SAMSUNG VC models under consideration, the following components and parts may first be needed: BVG - ASS'Y-DRUM (ASS'Y - prefabricated unit), DE-4UPN-SS (PART NO - 69063-214-360); cassette receiver - HOUSING-ASS"Y, STS304/ STS303TO5DE4 (PART NO - 620051-0012-00); filling engine - MOTOR-LOADING, DE-4U (PART NO - 66823-0055-00); driving engine - MOTOR-CAPSTAN, DE-4U (PART NO - 66823-0047-00); pressure roller - ARM PINCH RASS'Y, DE-4A (PART NO - 61543-0063-00); program switch - SWITCH-MODE ASS'Y, SRZZOA083ADE-4U (PART NO - 66202-0012-01); program gear - ASS'Y-GEAR CAM MAIN, DE-4A (PART NO - 69063-214-244).

Literature

1. Catalog "SONY IN SIDE" No. 9 for 1998/99
2. Petropavlovsky Yu. Household video cameras. VHS-C camcorders - features, circuit design, repair. - Radio, 1997, No. 11, p. 6-8.
3. Petropavlovsky Yu. Video equipment of VIDEO-8 format. SONY is the developer of the format. Signalogram, repair. - Radio, 1998, No. 2, p. 8, 9; No. 4, p. 10, 11.
4. Repair and adjustment of the tape transport mechanism of video cameras, VCRs and players. - JSC GONTAR, 1997.
5. Repair and adjustment of tape drive mechanisms of VCRs and video cameras, vol. 6. - 2000.

Author: Yu.Petropavlovsky, Taganrog

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