Series 3700A Switch and Control Cards Reference Manual Section 5: Model 3721 multiplexer card3700AS-909-01 Rev. A / Preliminary 5-7Amps channel fuse replacement procedureWARNINGDisconnect all external power from the equipment and the line cord before performing anymaintenance on the Series 3700A.Make sure that the Model 3721 card is removed from the system before replacing the ampsfuse (see next figures).CAUTIONDo not use a fuse with a higher current rating than specified or instrument damage can occur. If theInstrument repeatedly blows fuses, locate and correct the cause of the problem before replacing thefuse.To replace the amps channel fuse:1. Remove the top shield cover:A. Unscrew the number 4-40 screw (1) as shown in the "Shield removal" figure below.B. Slide the top cover in a direction away from the D-sub connectors, disengaging the cover from theprinted circuit board.C. Lift the top shield cover off of the printed circuit board.2. Set jumpers per options listed below.3. Replace the top shield cover.• Slide the top cover in a direction toward the D-sub connectors, engaging the cover onto the printedcircuit board, and securing with the number 4-40 screw (1).4. The card can now be returned to service.Figure: Model 3721 shield removalFigure 12: Model 3721 shield removal
