MOTM

John,  It sounds as if you pedal may be defective.

To facilitate the explanation, let's refer to the connection points on the
1/4 stereo plug by the commonly used terms
These plus are commonly called TRS for "tip" "ring" and "sleeve".  The tip,
well that is obvious.  The "sleeve" is the part on the other end (the
longest connection point) and the "ring" is the metal connection point
isolated between the sleeve and the tip.

With your meter set to read resistance, on a Yamaha pedal, you should get a
constant number when connected to the tip and sleeve.  This number is fixed
by the resistance of the pot and will not change for any pedal position.
For modern Yamaha pedals, this number is around 50K ohms.

Connecting to the tip and ring will yield a number that varies and is
highest with the pedal in the back position, and almost zero when the pedal
is fully forward.  Connecting to the sleeve and ring with your meter will
vary also according to pedal position, but just opposite with the near zero
reading corresponding to the pedal in the back position.

Larry Hendry

----- Original Message -----
From: corelli44 <john@...>
To: <motm@yahoogroups.com>
Sent: Thursday, February 07, 2002 3:53 PM
Subject: [motm] Foot Pedal Question


Hello List,

I have an old Volume/Modulation pedal that I got with my original DX7
back in 1985. I'm trying to measure the resistance to see how to use
it with the pedal interface but I'm not getting very clear numbers.

I get readings between 25 and 40 most of the time with the pedal up
or down. It does go up to as high as 150 sometimes but very briefly
(could this be my DVM? It's quite cheap).

Also, I only get readings with leads on the very tip and behind the
first ring on the plug. I get nothing with one of the leads between
the two rings (and the other on either side of either ring). Is this
the way the newer Yamaha pedals are wired?

I'm just wondering if older pedals might have been made a bit
differently than the newer Yamaha pedals or if they should be
somewhat similar (if anyone has any experience with older pedals).

I appreciate any suggestions or insight anyone might have!

Thanks,

John Broaddus






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