National Multiplex data cassette tape drive

From: Dwight K. Elvey <>
Date: Wed Aug 25 13:57:52 2004

>From: "Tom Jennings" <>
>THe worst part -- the motor had a trimpot in series with it, and that
>was the sole motor speed control -- and! -- tapes written at one speed
>adjustment could not be read at another speed!
>Of course I turned the pot, my fault. But just tapping it was enough. It
>was total crap.

 Most of these motors used an internal centrifugal speed
governor. These were designed to work within some span
of input voltage. I would guess that the pot was to drop
the voltage to be within this range. If one was to adjust
the pot, there should be a range of adjustment that the
speed ( with load ) was relatively constant. One would
adjust the pot to be safely within this span.
Received on Wed Aug 25 2004 - 13:57:52 BST

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