HETTICH CENTRFUGES 30-DAY DEMO
It occurred to me that I may have led you astray here. By "OV" did you mean "old version", the one that looks like this? http://www.labequip.com/kz-content/images/large/IEC-Micromax-Microcentrifuge-6221.jpg
I have a similar problem, and yes, I do have the model that you posted an image of.
The procedure is:
1. Unplug the centrifuge.
2. Find the plastic plug beneath the centrifuge.
3. Prise out the plug with a screwdriver.
4. Pull on the attached cord to open the lid.
(If the cord is not attached then use a piece of plastic-coated wire to try to hook it)
5. Replace the cord & plug in the hole.
IT IS DANGEROUS TO DO THIS UNLESS TH UNIT IS DISCONNECTED FROM THE POWER.
IT SHOULD NEVER BE ATTEMPTED DURING ROTOR ROTATION.
The fuses are at the rear of the unit. Replace with same power rating. Model 3590: 6.52A, 3591: 4A, 3592: 8A, 3593/4: 6.3A, 3595: 8A, 3596: 10A. I cannot say which model as you do not state your country.
You can get a user manual here: http://www.scribd.com/archive/plans?doc=60089985
Hope this helps.