Tape Loading Mechanism VHS-C Camcorder Saba VM-6991 CCD

As a demonstration video for my blog, I created this video which demonstrates the misc. functions of the tape loading mechanism of a VHS-C video camcorder, model Saba VM-6991 CCD (technically identical to JVC GR-65) with 270° head wrap. It shows different drive functions like tape loading, playback, fast forward/rewind, stop, eject, ... always explained by a short German introduction.

Category:

Howto & Style

Tags:

• VHS-C
• Camcorder

[rml695]

That camera looks awfully similar to one that JVC had back then.

[vcrcollector]

Yes, it's a JVC GR-65 relabeled by Saba. There also was a S-VHS version GR-S77.

In a normal VCR, the drum spins as fast as you have full frames per second (PAL/Secam as here: 25 rounds per second = frames per second with 50 fields, each head records/reads a field - the tape is wrapped 180° around the drum - and at NTSC 29,97 rps = fps with twice fields per second)

But as this is a special camcorder head drum which has heads all 90° instead of 180°, I think it is half that fast (12.5rpm)

[IRJustman]

Because since VHS uses azimuth recording (the head gaps are angled in opposite directions from perpendicular to the head's travel plane), opposing pairs of heads have the same azimuth angle. For the sake of argument, heads 1 and 3 have positive azimuth angles, while heads 2 and 4 have negative angles. As head 1, a positively-angled head, is about to leave the tape, while the negatively-angled head 4 is about to start on it. Heads 2 and 3 are already on the tape, but are switched off.

[IRJustman]

The reason there are four heads on the drum which rotates a bit faster instead of two is that because of the 270 degree wrap on a smaller drum so as to maintain compatibility with full-size VHS in terms of tape-to-head velocity and helical tilt. As the first head is about to leave the tape, the second and third heads are already passing across the tape surface already with the fourth head about to start touching it. (More)

[IRJustman]

vcrcollector: Sorry for being late to the game, but it's actually about 50% faster, so 2700RPM (45RPS) for NTSC or 2250RPM (37.5RPS) for PAL/SECAM. This is to take into account that the tape is wrapped 270 degrees around the scanner drum and that the drum has four heads instead of the minimum of two.  The hed firing order is, if you number them order around the circumference of the drum, one, four, three, two.

[guimbadriver]

Saba and JVC is the same thing...

[yesgeorge333]

can they have other lenses?

[SaGruenwdt]

ichw ar nie fan der VHS-Cs da auch das normale VHS schon immer technisch nicht das beste war. ich habe 1991 deswegen schon auf Video8 gesetzt. alleine wegen der viel besseren audio aufzeichnung (schrägspur) war es für mich erste wahl.

[sodasoap]

Look similar to GR-65 for sure even sound the same

[VideyoJunkei]

Each 'field' is recorded for 3/4 revolution, then it "jumps" forward 1 head, then uses that for 3/4 rev...it has to spin faster for this. Since the drum is smaller, and the path is the same length (these tapes will play is a VHS with an adaptor.

[Silverwolfstarz]

VHSC was model after the Bate Tapes  i think

[nero486]

ich hatte mal ein VHS Laufwerk ohne Video Play gestartet, so konnte ich mit offenen Bandspuhlen von Hand Kurbeln (Bremsenfedern gelöst).Das geht aber nur mit normalen Videoköpfen. Neue Videorecorder zeichnen einfach im SP Modus mit der schmalen LP-Spur auf.