okay I read in the MB manual that in order to test the diode of the OVP, you connect a multimeter across terminal 31 (+) and terminal 30(-) and observe the voltage reading. I got 0.522 volts (bouncing a bit), which theoretically means that the diode is okay. However I want to open it inside and to check the solder connections. The number is 201-540-32-45 with one fuse and 2 metal contacts at the top. What are the contacts for????????????and how to open the casing??? it seems that these contacts are holding down the black cover.
any ideas