Teardown: Sony MP90 Video8 Cassette (and other cassettes)

We come to the end of a line of cassette-inspired posts with an examination of Video8 cassettes. These were the consumer-favourite which succeeded VHS-C in portable applications, being smaller and allowing for longer duration recording while providing a similar level of quality visually, and slightly better quality audio.

These originally used 8mm Metal Particle tape – twice as wide as DAT, with improved Hi8 (analogous to SVHS) using either MP or Metal Evaporate tape. The final iteration for the 8mm format was Digital8, which used DV codec and stored digital video identical to that used in miniDV, except using 8mm cassettes instead. The 8mm cartridges also saw applications in data storage in Data8/D8 systems with capacities from 5 to 60Gb.

As we had upgraded from VHS-C to Video8, I still have two Video8 cassettes and a cleaning cartridge in my possession. Sadly, the deck had long failed, and loved to eat tape. Luckily, I had already digitized all of our collection, although the quality could probably be better.

Sony MP90 Video8 Cassette

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Video8 cassettes are roughly an audio cassette sized cartridge, which is almost twice as thick. It comes in a fold open plastic jewel case.

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At a glance, the cartridge can be seen to have many similarities with Mini DV tapes. In fact, I would have to guess that Mini DV was very much inspired by the design pioneered by Video8.

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The top of the cartridge shows a large window exposing showing the state of both reels inside. As with most analog recording technologies, tape duration and system are tied together, so this cassette is a 90 minute cassette in PAL SP Video8 mode.

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A labelling area is provided on the spine, with a slide record switch that shutters a sensing hole at the bottom of the tape.

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The two sides haven’t many features, although on the left side, there is a lid latch release lever which allows the multi-part lid to flip open and reveal the tape inside. This is on the opposite side compared to Mini DV. The multi-part lid design, however, is very similar, covering the tape from top and bottom sides.

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Similar to full size VHS and DV, there is a end of tape sense hole in the middle, a reel lock release at the bottom-middle and two identical reel drives on the bottom.

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The inlay card is colour printed on one side only, with both sides available for notes.

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A partially used label sheet is also found – note that the cassette dates of 1997-1999 on the labels provided, indicating this is one of the later Video8 cassettes (as Video8 was introduced in 1985 and gained some popularity by the mid-90’s).

Teardown

Five screws had to be removed to separate the halves.

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The top lid features two independent metal piece springs to provide reel support, and the bottom section of the lid guided by rails.

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The other half features the cassette where the supply reel has some severe damage to the top plate, possibly caused by severe shock to the hub area. The layout internally is very similar to the Mini DV cassette, featuring no rollers whatsoever or dust wipers. Instead, the tape freely runs over the case edges, which are carefully shaped to minimise scoring and friction.

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A clear leader tape is used, with optical sensing of end of tape.

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The reel locks rely on the notches on the rear plate, with a single spring-supported piece having two “fingers” which are guided by channels in the case. When the single piece is pulled downward against spring pressure, these flexible fingers pull back from the notches in the rear plate, letting the reels spin freely.

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Other Video8 Cassettes

Since I went to the effort of photographing one cassette, I might as well photograph and post about the others in my collection.

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This, for example, is a partially wound TDK 120 minute (NTSC, I believe) 8mm cassette. It has a different patterning on the rear, and a labelling area on the front.

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The write protection switch is also different, as its physical appearance from the spine is unimportant, as it is sensed by a pin from below.

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Similarly, the inlay cards feature colour on one side and monochrome printing on the other.

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A set of labels belonging to this cassette, and a set of labels belonging to a Hi8 version of the cassette were found, with care instructions printed on the rear.

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A cleaning cassette was also found, with all of the cleaning cassettes a dry type from memory. This one was clearly pre-labelled with a blue lid. The tape inside is black in colour with a less smooth finish.

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Inlay cards with instructions for use were also found.

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Conclusion

The use of tape in the consumer space has been receeding over the years, so it was nice to take a look at these different sorts of tapes towards the end of their lives and get a peek inside under the shell, while also preserving some of their looks and feels for nostalgia sake. With the superior storage capacity of hard drives, it was clear that the market for tapes would be limited as soon as JVC launched their Everio series of recorders, and again, with the introduction of flash based cameras, it was clear that the era of the hard drive recorder was also coming to an end.

The march of technology is relentless, although if there’s one thing tape seems to do well, some formats seem to archive a lot better in the long term compared to low-cost optical disks provided you can still find the equipment to play it back. The analog formats degrade somewhat gracefully, and the digital formats can have enough error correction to survive unscathed for 10-20 years provided it is stored in the right conditions.

About lui_gough

I’m a bit of a nut for electronics, computing, photography, radio, satellite and other technical hobbies. Click for more about me!

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2 Responses to Teardown: Sony MP90 Video8 Cassette (and other cassettes)

  1. sparcie says:

    I actually have one of the relevant data tape drives. I couldn’t work out what it was for a while as the drive had no obvious markings. I didn’t have much luck finding media for it. I’ll have to see if I can tear it down some time.

    • lui_gough says:

      Very interesting! Do have a check, because Sony also produced AIT drives using 8mm media, but a slightly different type of cartridge with an IC chip memory as well. Data8 was not particularly common if I recall correctly, as helical scan had a reputation for reliability issues and needing more frequent head cleans. There is a possibility a regular Hi8 video cartridge could work in a Data8 deck, but I wouldn’t know for sure. At that time, I suspect many users were still using late QIC drives (e.g. Travan) or migrating over to CompacTape/DLT/LTO with non-rotating heads.

      – Gough

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