Error 5

This question is about a LabNet Vortemp56 Temperature Chamber Shaker. I am getting an Error 5 (Err5) after 3 seconds from a Start. The User manual states that this error usually appear when the user open the lid while the unit is running, making a temperature distortion, hence the operation error 5. None of that is the actual case. The error appear just after starting a session. The lid stay close. I suspected the Lid Switch or a sensor broken. It is not the case. If anyone happen to have a service manual for this apparatus it would be greatly appreciated if you could upload it. Cheers