Phil Marlowe wrote in a message to Roy J. Tellason:



RJT> Yeah, that's what I was thinking about, yanking the tuner portions 
RJT> out of one or more of the dead ones I have in storage for parts.

PM> Do you have to go to the trouble of yanking the tuner portion from 
PM> the VCR? Can't you rig it up by simply connecting the old VCR to 
PM> your TV -- using the TV as a monitor? You can't play tapes but you 
PM> can then at least use the VCR's remote to switch channels.

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

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

Anyhow,  if there's a problem in that regard,  the unit will do absolutely
*nothing* from that point onwards.  I've seen this happen due to a bad
belt, among other reasons.

Power supplies in the units I was working on back then were typically
linear, with some bits staying on all the time,  and other bits that were
switched when you exercised the power switch on and off.  I guess some part
of the computer chip stays active,  as well as the clock.

Since a bunch of what I have sitting in storage is non-functional to some
degree or other,  it seems to me that the logical approach would be to yank
the tuner bits out,  figure out what power and wiring they wanted,  and go
from there in an attempt to try and use them.  Hopefully I'd have service
data on these particular units to ease that...

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