John wrote in message ...

have you recently changed tape speed or time code frame rate?
If you do, you have some parameters to change on the appropriate SY
module for that machine. (mmmm, programming in Hex code with MSB/LSB)
this sounds possibly like a tach pulse counting issue. The reason it
goes away after a while is because it is learning the ballistics of the
machine and adjusts. Do you know what level software is in the SY unit?
Once the unit is set up, it is very bulletproof, but requires parameter
adjustments if you make changes to the tape machine like speed or frame
rates.

No, we didn't change anything. And, as you said, it's been bulletproof
for years. The only thing the technician changed recently were some
ICs on the track-arming boards. I'll check the software, though.

it's been years but I used to fly a big 2600 system and still have it in
boxes with the manuals and cables. Need any spares ?

I'll ask our technician, but these units are built for eternity :-)
Thank you very much, it's good to know there are still experts for
equipment like that out there.
It's sad that many engineers/assistants in my age (24) don't have a
chance to work with good old big tapemachines..

Sebastian