E-bay item ??

[Charles W. Morehouse]

Folks,
Have two IO-10 scopes. One is restored and one to be. Built one back in the
60's and used it for a while to monitor my stereo signals. It is long gone
but found these two. The unrestored from the bay. The other, found locally,
I think IS the one I built. You can tell volumes by the pattern when X and Y
channels are hooked to the left and right channels. So the restored one is
in the entertainment center and is used frequently. Great little scope for
LF work but a little drifty until it warms up and it runs pretty warm.
Later.
Wayne;
W4GBW


Glen Zook wrote:

> As an "aside", the Heath IO-10 oscilloscope was sold
> by Motorola Communications & Electronics (the two way
> division of Motorola back in the 1960s and 1970s)
> assembled as their model T1015.  The front panel is
> lettered differently as well as having the Motorola
> model number and a printed Motorola logo.  On the side
> of the case is a large metal Motorola logo.
>
> Also, the reticle on the scope tube is calibrated for
> reading FM deviation.  The right hand side has
> calibration for +/- 5 KHz of deviation and the left
> hand side has +/- 15 KHz of deviation.  When an
> oscilloscope is used with a Foster-Seeley type of
> discriminator it is possible to read deviation very
> accurately by coming directly off of the discriminator
> output.  The end points of the deviation are
> calibrated by using known offset frequencies from the
> actual i.f. frequency.
>
> The older Motorola test sets actually had three
> crystals built in for this purpose.  They were 455 KHz
> for the center and 450 and 460 KHz for the end points.
>  This was for two purposes:  The first was the check
> the "Permakay" i.f. filters that were used in Motorola
> equipment well into the 1970s to insure that they were
> still symetrical and to set the discriminator to
> exactly 455 KHz.  The other use was to set the end
> points for deviation measurements.
>
> You ask how I know this?  I have owned a T1015 since I
> worked for Motorola directly my senior year in college
> (1966).  The case was slightly damaged when the unit
> was sent new to a customer and was returned for
> credit.  Motorola never returned a piece of test
> equipment to the manufacturer, but just went ahead and
> replaced it.  The parts department gave it to me (and,
> over the year that I worked there, several other
> pretty nice items).
>
> For a general purpose oscilloscope, it is pretty good.
>  By the way, when you read FM deviation you are only
> reading DC voltage, the discriminator has already
> demodulated the 455 KHz (or whatever) i.f.
>
> Glen, K9STH
>
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