Midi channel settings, Technics KN7000 to Organ

I have used a KN 7000 very successfully as a rhythm unit connected to several makes of organ. in the past .Not always easy to set up but what a difference the extra rhythms make. The most important setting is for the lower keyboard of the organ to send chord changes to the Technics for the auto accompaniment this has always been on Midi channel 3. in the organ
Unfortunately for me I changed organs recently and the keyboard would not respond even though all the settings were the same and it was only by accident I stepped on an organ pedal and the Technics immediately played an intro !
So I found where he signals were going to ! the chord change was transmitted on the channel 2 to which the pedal was set, so I simply set the midi setting of the lower manual to channel 2 in the organ and all was back to how it used to work.
Unfortunately the organ ( Roland Atelia AT 80 does not have global settings so although I changed the setting once switched off and on again it reverts from channel 2 back to channel 3 and does not work again.
Some organist knew about this feature and told me it was possible to alter the Technics Midi receiving setting instead but did not know how to go about it and I wondered if any forum member did, . I would be very grateful for any information.