2014-06-06
After having removed the case and seen a blocked machine (carriage solid as a rock to the frame), I sprayed the obvious vital parts of the machine and let the machine for observing the differences with the 300D

2014-06-26
Curious how the machine is doing. I moved here and there a little see what the reason for blocking is. I got the central axis running with the special crank . The carriage was loose. The update of the revolution counter was causing a little more force at the crank. The motor was free to turn by hand a number of cycles. The big front register coupled with the Switching Latch Wheel was possible to turn. Set each digit to zero. Turned the motor on and the machine made a few calculation cycles and was blocking again.
Seems the revolution counter is blocked. N digit can be turned. See how it works / how it should operate first.

2015-11-20
With the appreciated repair work of the dutch collector T. Henst, the machine is functioning again. He has a 505 as well and has offered me to take care of my machine as well. He made some pictures of the machine in the carrier dismantled state.
First a remark on the interference filter (coils and capacitor net work) has exploded in his machine so he removed it electrically in mine machine. Please see the open wires below the motor.

2015-11-28
He remount the carriage, due to blocking of the revolution counter gears. The pictures he made from this, are numbered from 100 onwards.