Hi Hank,

High, Medium and Low are used to select the maximum voltage that is
applied to the device under test. All positions are harmless to all
known semiconductor devices.

When the probes are open circuited, you should see a perfectly
horizontal line in High or Medium, and a diagonal (corner to corner)
line rising from left to right, in the Low position. I stated this
incorrectly in my post.

When the probes are short circuited, you should get a vertical line
in all three positions.

If you connect to a low value cap, you will see an oval that is more
horizontal than vertical, if you connect to a higher value cap, the
oval will be more vertical than horizontal.

The patterns will change depending on the selection of High, Med and Low.

Try testing a zener diode. You will see that in the low position it
looks just like a diode, in the medium and high position, it will give
a zig-zag pattern.

It sounds to me like your unit is working just fine!

-Chuck

Ps, Please post and copy to my email! When people do that, I end up
writing two replies to the same post. If you want a personal reply,
then just use my email.

Henry Kolesnik wrote:

I agree it's pretty simple but a little correct info would go a long way!
I don't know what high med and low pushbuttons are supposed to do?
I just tweeked a few unlabeled pots carefully to see what effect they
had....
And adjusted some that had the "right" effect...
With nothing connected I now get a horizontal line on high and med
but a 60
degree slanted one on low!
With leads shorted I get a nearly vertical line on high, med and low!
A 22mf cap gives a decent circle on high and med but a 60 deg. slant
line on
low..
A diode gives an L on high and med but a V on low...