Jasen Betts wrote in a message to Roy J. Tellason:

 RJT> No,  the data sheet specifically mentioned vcr and audio cassette
 RJT> applications. I can see reversibility being a good thing if 
 RJT> you're running a tape cassette and have a bidirectional 
 RJT> capability in the deck -- you'd have the mechanism switch
 RJT> capstans, but the motor would also need to spin in the other
 RJT> direction.  VCRs? Hm,  that's a little more difficult, I'm not
 RJT> that up on the mechanicals of those

 JB> I think the intention is to drive the servo that loads tape round
 JB> the head and switches the tranmission (FF/REW/PLAY need different
 JB> mechanical configurations
 JB> etc.

That could be,  too.

 JB> I think newer VCRs may be using the same motor that drives the 
 JB> captans etc to switch the transmission (takes a whole mess of
 JB> annoying little plastic gears) 

I hate it when they try to economize like that.  It never works quite as
well. This is probably the reason behind the suggestion I saw that said
that if you had an earlier machine it probably paid to keep it running, 
because they were built like tanks by comparison with the newer stuff.  And
I can believe it.

 JB> I seem to recall my answering machine uses a similar setup. 
 JB> reversing the motor changes gears, loads and unloads the heads and 
 JB> pinch roller, running it forwards drives the tape.

I never got that far into the mechanicals of mine.  I got given a box of
old answering machines some years ago,  one guy I knew looked at this one
and decided that it needed a head,  which we were able to get at that time,
 and since then I've only put belts in it,  which was after maybe 15 years
of using the darn thing.  (Probably oughta clean the heads one of these
days. :-)  I don't remember there being all that much in there,  but it
uses two of those baby cassettes,  and the electronics board has an 8048 on
it.  :-)

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