On Wed, 22 Mar 2006 16:59:41 -0800, "David Farber"
put finger to keyboard and composed:


"Bruce Esquibel" wrote in message
...
Franc Zabkar wrote:

: The belt is fine, and the top and bottom halves of the idler lock
: together in rewind and FF modes. There is no slippage. The only real
: drag appears to come from the weight of the tape. In FF/REW modes the
: capstan runs in open loop mode, ie the motor is supplied with a fixed
: voltage. The tape is fully retracted into the cassette housing and the
: pinch roller is disengaged. Both plastic levers and pins are intact.
: I've replaced a sticky brake pad on the take-up lever and the
: performance has improved, but it's still a little on the slow side. It
: looks like it might be just designed that way shrug.

You know you might not be that far off with that last comment.

I'm not totally sure of the that model number but if this machine is from
the mid/late 80's, I had a DX-5000 bought new and in all the machines I
ever
owned, it had the slowest rewind/fast forward.

I mean I'm talking about 7-10 minutes easy to rewind a T-120. It didn't
take
long to fail completely, within the first year it couldn't rewind the tape
all the way and from that point, needed the idler tire changed twice a
year
if not more often.

At first I thought the generics from MCM were just poor, going to NEC
direct
was expensive (whole idler, not just the tire) and didn't help.

Eventually I think I ended up using the reverse scan.

I really liked that machine, was some weird non-standard vhs compared to
everyone else, had some kind of real ram based digital memory with a bunch
of tricks that could be utilized. Was the first vhs that could do frame by
frame slow-motion without noise bars because everything was read off the
ram. Some kind of built in TBC (sort of). Could freeze frame an image and
toss it into a PIP mode with the tape still playing in the background.

But mechanically it ranked in the bottom on my list.

-bruce


Ditto on the DX-5000 machine. I have one too and you might as well read a
book waiting for it to rewind. The whole NEC line of that era just didn't
rewind with any speed at all. The 7-10 minute waiting time seems very
accurate.

The supply voltage to the capstan motor is derived from an RC PWM
circuit. I managed to increase the rewind speed by reducing the value
of R (R618). Changing the take-up brake pad also helped.

- Franc Zabkar
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