I am trying to find a replacement for an obsolete encoder. I thought I had found a good replacement, hiwever the unit increments up when turned both ways, instead of up for right and down for left.

What is different about this encoder and the old one? What would be a good search term for one the correct type?

old vs new part

old part wafer (cracked)

Alright, it was just a weird pinout on the old part. Thanks to everyone, especially Ron Beyer!

  • \$\begingroup\$ unit increments up when turned both ways .... what is incrementing?? \$\endgroup\$
    – jsotola
    Jan 30, 2019 at 21:30
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    \$\begingroup\$ EC16B25D0 Is the part number of the old part, or atleast what the service manual calls it. The new part I am trying is a 652-PEC11R-4215F-N24 from Mouser. \$\endgroup\$
    – Kruya
    Jan 30, 2019 at 21:31
  • \$\begingroup\$ Its for the Data Entry on a Roland TD7 Drum Machine. So say volume or whatever setting is active will count +1 in either direction \$\endgroup\$
    – Kruya
    Jan 30, 2019 at 21:33
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    \$\begingroup\$ These encoders have an "A" and a "B" line. If the "A" line is high before "B", then the encoder should count up, if "B" is high before "A", the encoder should count down. It is possible that the pin-outs don't match and you are only seeing the "A" side. \$\endgroup\$
    – Ron Beyer
    Jan 30, 2019 at 21:44
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    \$\begingroup\$ The part on top of the picture is a rotary encoder. It gives electrical pulses as you turn it. The part on the bottom is a potentiometer. It changes resistance as you turn it. That's two completely different parts! Are you sure Mouser sent you the right part? Because non of the parts numbers you mentioned in the comments match a potentiometer... \$\endgroup\$
    – MartinF
    Jan 30, 2019 at 21:44

1 Answer 1


The common pin is shown in the following pictures.

Connect the new encoder common to the old encoder common.

Then connect the other two and test.

If the new encoder works backward, then swap the two outer pins of the new encoder.

enter image description here enter image description here


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