Hidelberg SM74 Perfector error

hello
I have perfector error flashing as an in attachment photo
the machine is 2 color and in straight now
I need to reverse it
can you help me to fix the problem

 

Please send us Press model and serial number.

 

model: SM 74-2-P
Serial : 623261
1998

I checked the variant code they are OK

 

the machine 2 printing unit

 

The error on the picture says: missed sheet during the turnover.
That would mean that you must have the press in double side mode not in straight in order to generate such error. The second disagreement here for me is why there is a number 3 in error code, because that would mean: missed sheet in Printing unit 3 (PU3), on a two color press???
Maybe im wrong in my thinking but something here is not OK.
Can you run the press in straight mode without problems?
Did you use the original variant code of the press- which you usualy find in the main cabinet to- check?

 

yes the machine work in straight without problems
yes I use the original variant code

 

Than check first the switch S19 on the vacuum box, this system checks if you have a missed sheet.

 

Thanks for your help
Mr. Mechanica Speedmaster
the problem in the sensor 2S40

 

Nice job!!!