"Roy J. Tellason" wrote to "Phil Marlowe" (07 Jul 03  20:01:15)
 --- on the topic of "VCR"

 PM> I'm assuming here that only the tape mechanism on the broken VCR is
 PM> defective, and everything else works.

 RJT> Well,  it depends.  One of the things that took me a while to find out
 RJT> back when I was fixing this stuff was that a typical VHS machine will
 RJT> do a little mechanical bit when you first plug it in.  Not when you
 RJT> first turn it on,  but when you first plug it in!  This bit consists
 RJT> of a slight movement of those two arms that pull the tape out of the
 RJT> cassette.  The idea behind this is apparently so that the computer
 RJT> chip in there knows what the state of the mechanism is,  and what's
 RJT> where.  There are apparently limit switches or other position sensors
 RJT> that affect this.

I experienced something concerning limit switches with my old vcr today.
Apparently a transformer blew up in the neighborhood and the power
glitch zapped my tv's G2 so that the picture suddenly went darker than
usual. No problem I thought I have a spare on the work bench I just
replaced the vertical IC in and running a burn-in. So the old vcr get's
unplugged and in the melee, to swap out the TV's, gets handled a bit.

Plug everything back in and the old vcr's cpu decides there is a tape
loaded, even though it hasn't seen a tape in years. Whirr, clunk,
flashes the tape logo and promptly turns itself off. Power it up again
and ditto repeat. So I unplug it for a few minutes and try again. Same
weird routine! The thing is it normally never does anything when plugged
in, ever (the JVC's do however).

So is dawns on me the tape loaded switch has a film and the handling may
have moved things in it slightly. I jam in a cassette with the power off
so it just goes in part way a few times and when I power it up again, it
was back to its normal condition. Unplugged it to be sure and it behaves
itself.

Just to say that not all vcr's behave the same when first plugged in.
The JVC's that go through a little movement actually don't use a tape
basket switch but depend on a timing gear for position information.
That's why they love to eat tapes when things go even slightly wrong.

 Mike
 ****

... Don't anthropomorphize computers.  They don't like it...
--- Blue Wave/DOS v2.30