CSF Service Bulletin 01, 24 December 1999.

CSF Channel shifting under running status problem

This problem can occur with all CSF units shipped before 10 December 1999. On faulty units, the second character of the serial number is less than four. If the second character of the serial number is four or higher, the problem has already been corrected.

The CSF had been shipping in quantity for over a year when this problem was reported on 9 December 1999. It has only been reported once.

In three of the processing functions of CSF, when the channel switch is not set to 1, channel-shifting occurs. The relevant functions are as follows:

the selected channel solo and shifted to channel one
pass channel one solo shifted to selected channel
shift all channels "round the clock" by selected offset

Some MIDI master devices use "running status", which is a technique to improve the speed of MIDI communications. If a CSF is performing channel-shifting, and the master device uses running status, the MIDI channel tags may be corrupted.

Messages thus corrupted may be lost or may be retransmitted on the wrong MIDI channel. The problem is likely to be worse as the input MIDI datastream gets busier.

Please accept our apologies for any inconvenience caused by this problem.