On 1/31/24 11:12, Mike Katz via cctalk wrote: > I have not yet tried installing terminating resistors...
That might help. It's also possible that the LED/phototransistor for the SS index position is faulty. The two LEDs (SS and DS) are connected in series, so you know that at least one isn't open. Grab your DMM and check the voltage levels on pins A6 and A7 on connector J2. They should change as the beam is broken in each with a piece of tinfoil or something else opaque. --Chuck