Amps Channel Fuse Replacement Procedure - Keithley 3720 User Manual

Section 9: Series 3700 Module Schematics and Connections

Amps channel fuse replacement procedure

WARNING
CAUTION
1. Remove the top shield cover:
2. Replace the fuses:
3. Replace the top shield cover.
4. The card may now be returned to service.
9-18
Disconnect all external power from the equipment and the line cord before
performing any maintenance on the Series 3700.
Make sure 3721 card is removed from the system before replacing the
AMPS fuse.
Do not use a fuse with a higher current rating than specified or instrument
damage may occur. If the Instrument repeatedly blows fuses, locate and correct
the cause of trouble before replacing the fuse.
x
Unscrew the #4-40 screw (1) as shown in the "Model 3721 shield removal" figure below.
x
Slide the top cover in a direction away from the D-sub connectors, disengaging the cover from
the printed circuit board.
x
Lift the top shield cover off of the printed circuit board.
x
The fuse locations for channels 41 and 42 are shown in the "Model 3721 fuse location" figure
below.
x
Gently lift out the old fuse from the fuse holders. Holders are labeled FH1A-FH1B for Channel
41, and FH2A-FH2B for Channel 42. Pull the fuse away from the PCB and it should snap out
of the holders.
x
Place the new fuse by gently pushing it downwards towards the PCB into the fuse holders. It
should snap into the holder on each side. Make sure that the fuse body is inline with the
holders before applying force. Do not use excessive force. Check that the fuse is contacting
each holder.
x
Discard the old fuse.
x
Slide the top cover in a direction toward the D-sub connectors, engaging the cover onto the
printed circuit board, and securing with the #4-40 screw (1).
Series 3700 System Switch/Multimeter User's Manual
Document Number: 3700S-900-01 Rev. A / August 2007