| Signal Cards and Bypass Cards| Attention:|  If you are removing a back-signal card from a Model 010 or Model 500, ensure that| all the disk drive modules in the back of the 7133 are no longer available to the using| system.|  If you are removing a front-signal card from a Model 010 or Model 500, ensure that| all the disk drive modules in the front of the 7133 are no longer available to the using| system.|  If you are removing a bypass card from a Model 020 or Model 600, check the| configuration of the 7133 to find out which disk drive modules are affected by the| removal of this particular bypass card. Ensure that all disk drive modules so affected| are no longer available to the using system.| Note: Unless you have a particular reason to do so, do not turn off the using system or| the 7133 when removing or installing a signal card or bypass card.Chapter 3. Removal and Replacement Procedures 3-43

IBM 7133 Series Service Manual