[weblacky]

What is this padding (cardboard) of the scsi converter?

There isn't natively any padding, I asked if you ADDED padding because often in SGIs (example is an Indigo2 sled in picture below).  Without any protection you have this:

   

Look at the arrows in this picture.  There isn't ANYTHING to prevent the backside (bare solder joints) of the adapter from touching the metal drive casing...for both part of the power connector and the SCSI signaling pins. Because this situation is dangerous, unless some insulated padding is placed between the  board and drive casing...you can easily bend the plugged in adapter enough to touch the drive with those silverly, sharp, solder joints on the rear of the card.  In a tight situation like an Indy...you can do something like this!

Did the two bare parts touch when powered on?  This touching (where the yellow arrows are) could lead to damage/fire/melting/bad stuff.