Principles Of Operation; Power Supply; Figure 4-1 Power Supply Block Diagram - Keithley 2701 Service Manual

Model 2701 Service Manual

Principles of operation

The following information is provided to support the troubleshooting tests and procedures
covered in this section of the manual. Refer to the following block diagrams:
Figure 4-1
Figure
Figure 4-3
Figure 4-4

Power supply

The following information provides some basic circuit theory that can be used as an aid to
troubleshoot the power supply. A block diagram of the power supply is shown in
Figure 4-1
Power supply block diagram
Power
Fuse
Switch
— Power supply block diagram
4-2— Digital circuitry block diagram
— Analog circuitry block diagram
— Ohms open-lead sense detection block diagram
Line
Power
Voltage
Transformer
Select
Switch
Troubleshooting
+1.8VD
C66, C205,
+2.5VD
C214, U18
+3.3VD
U19, U25
D Common
+5VD
CR104, C156
C274, C274
C281, U144
D Common
+37V
CR116, CR117
C104, U101
D Common
+18V
+15V
CR102
C131, C148
A Common
U119, U125
-15V
-18V
+5V
CR103
C146
U124
A Common
4-5
Figure 4-1.