Sounds like the scroller is stuck in perpetual reset. I have some possessed Chroma-Q's that can do this if the optical sensor is dirty and/or tension is set wrong. Which vintage of Apollo is this? At one point they may have been OEM'ing the same product.
If 'twere me I would contact the good folks at Apollo or post it on controlbooth.com. Kelite (a.k.a Keith) works for Apollo and is a frequent contributor.
We have Apollo SmartColor 7's and I have encountered this on multiple occasions. Typically it is simply that the optical sensors have simply been knocked out of alignment or are dirty. On rare occasions I have had to have the DMX card replaced, but usually a little TLC to the sensors fixes things up.
I concur. It's usually the optical sensor out of whack or dirty. I have found that if the left drum is loose it will eventually knock the sensor out of alignment inside the case. Just need to bend it back down so it faces the notched wheel.
www.etcconnect.com