[rescue] LCD monitor diagnosis

Don Y dgy at DakotaCom.Net
Thu Apr 27 10:36:05 CDT 2006

wa2egp at att.net wrote:
>> At least these are "undeniable" (ahem) *features*.
>> I have a cassette tape deck that autoreverses at the end
>> of side A (etc.) to play the back side of the tape.
>> As expected, when it starts playing the back side of
>> the tape, the tape counter counts *down* (so, when the back
>> side is finished playing, the counter should have returned
>> to 0000 -- assuming it was started at this point on the
>> front side).
>> But, if you eject the tape as soon as it gets to the end
>> of the front side, manually flip the tape over and reinsert
>> it, and then press "PLAY FORWARD" (i.e. play the front side
>> of the tape), the tape counter STILL counts *down* -- even
>> though the tape reels are moving "up".
>> (can you spell "bug"?)
> Maybe I'm stupid but from your description, it sounds like 
> you are manually reversing the tape and the counter is
> counting the same way as it would with the autoreverse.
> You are moving the track to the head instead of the 
> autoreverse moving the head to the track, same effect.
> A bug? Makes sense to me....


Insert tape with side A "forward" and rewound.  Reset
counter to 0000.

Play tape ("forward"... tape moves from the right reel
onto the left reel).

Tape comes to end.

Stop tape *before* to starts to play the "back" side.
Counter reads XXXX (X != 0).  All media is on the
LEFT reel.

Remove tape.  Flip tape over (media is now on RIGHT
reel).  Press FORWARD PLAY (two play buttons on
the deck... forward/front and reverse/back).
Tape moves from the RIGHT reel to the LEFT reel -- as
it always does when playing "forward".  I.e. the
tape is physically moving in the same direction
it was previously!

*BUT*, now the counter is counting DOWN.

I.e. imagine taking an entirely different tape
that is "rewound" to the start of "side A" and inserting
it at this time in place of the tape that you were
just listening to (which is now *WOUND* to the start
of side B -- but will be loaded with side B "forward"
since the tape deck has no idea which "side" of the
tape is physically loaded as "forward").  You
would expect the counter to count UP for that tape.
Yet, in this situation, it will PLAY as if the counter
should be counting up (forward) but the counter will
actually count DOWN.

I see no way of rationalizing this behaviour other
than as a "critical region" bug.  I.e. don't remove the
tape while the machine is thinking about playing
the back side -- even though there is no PHYSiCAL
alteration to the mechanism taking place during the
"flip" (4 track head)

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