There are several on ebay right now. Here's one that will work: http://www.ebay.com/itm/BOURNS-ENA1J-B28-L00128L-OPTICAL-ENCODER-ENA1J-B28-L00128-/272413615479?hash=item3f6d1de577:g:F0AAAOSwyQtV4UlJ Curt, K8AI Sent with [ProtonMail](https://protonmail.com) Secure Email.