My facit N4000 reader/punch has developed a problem. Would anyone have a service manual for this unit? I have the operators guide but no service manual. When powering up the unit, about 20% of the time it comes on with "Err" in the display. If I turn it on and off a few times, it comes up correctly with "Off" in the display. Also, the test tape created in diag test #4 mostly, but not always, passes it's read in diag test#5. Can anyone help with a loan of the service manual or perhaps some advice? Regards, Jay West