Ampex ACR-25 Commercial Player Question

[TVBeeGee]

How many former Ampex ACR-25 folks are here? If you never used one or saw one, you would be amazed to see it work. All the threading was done by differential air pressure. No mechanical arms ever pulled at the tape. Through a careful ballet of various vacuums, tape seemed to magically leap out of its cassette and fly into position on the transport. You really missed something if you never saw one work.

There is a video on youtube showing ACR-25 transports in action, but it is too short and too low in resolution to give those not familiar with the machine a good idea of how it worked. It really was amazing.

Other than the relatively rare mechanical or electrical failure, about the only problem I ever saw with the ACR-25 was that the cassettes seemed to develop a cluster of dropouts at the beginning and ending of where a spot was typically recorded. I always wondered if this might have been caused by the video heads nicking the tape at the point where the head's vacuum guide rose or was retracted. The threading was extremely gentle, but this encouraged the cassettes to be used for many hundreds of plays and perhaps a very tiny amount of wear built up over time. For those of you who worked with the ACR-25, did you ever see these dropout clusters? Do you know what caused them?