Brother MFC-8710DW paper jam tray 1

[WebSerf]

I'm new here but I used to fix Xerox copy machines (about 40 years ago). I am trying to fix a multi function copier which gets "JAM TRAY 1" every time paper is fed from tray 1 but feeds and prints from the MP tray without any issues.
The paper stops between the registration actuators at the registration roller consistently as near as I can tell and there is no apparent lead edge damage that might be caused by an obstruction.
I have used maintenance mode to check the operation of registration actuators and the test codes indicate that they are functioning correctly but, when I pull the drum module and manually operate them to check them, I hear a click when I actuate the front actuator that sounds like a relay or solenoid and I do not hear a similar click when the rear actuator is operated.
Any help or guidance will be greatly appreciated.
Thanks,
Bud McGregor

 

[WebSerf]

Upon further study I have come to believe that the click I hear may be a clutch which supplies drive to the registration roller but I don't understand why the jam occurs only when feeding from tray 1 but gets no jam when I use the MP tray. If anyone knows where I can get a sequence of operation that would help me to understand the dependencies and interactions of the switches and drives.
Again, thanks,
Bud McGregor