![background image](http://html1.mh-extra.com/html/keithley/2500/2500_service-manual_3998319064.webp)
Troubleshooting
4-5
Overall block diagram
shows an overall block diagram of the Model 2500. Circuitry may be divided
into two general areas:
•
Analog circuits — includes measurement circuits such as the I/V converter, mux,
and A/D converter, as well as voltage bias circuits.
•
Digital circuits — includes the microcomputer that controls the analog section,
front panel, and GPIB and RS-232 ports, as well as associated interfacing circuits.
Figure 4-1
Overall block diagram
Front Panel
Keypad
2 Line VFD
GPIB
RS-232
Digital I/O
Trigger Link
OPTO
Interface
Channel 1
Voltage Source Channel 1
±
10V,
±
100V
20mA Max
I/V Converter Channel 1
(8 Current Ranges
2nA - 20mA)
OUTPUT 1
INPUT 1
I/V Converter Channel 2
(8 Current Ranges
2nA - 20mA)
Voltage Source Channel 2
±
10V,
±
100V
20mA Max
A/D
OPTO
Interface
OUTPUT 2
INPUT 2
MC68332
Microprocessor
Channel 2
A/D
D/A
D/A
Summary of Contents for 2500
Page 2: ...Contains Calibrating and Servicing Information Model 2500 Dual Photodiode Meter Service Manual...
Page 11: ......
Page 13: ......
Page 15: ......
Page 16: ...1 PerformanceVerification...
Page 28: ...2 Calibration...
Page 56: ...3 RoutineMaintenance...
Page 59: ...3 4 Routine Maintenance Model 2500 Service Manual...
Page 60: ...4 Troubleshooting...
Page 74: ...5 Disassembly...
Page 81: ...5 8 Disassembly Model 2500 Service Manual...
Page 82: ...6 ReplaceableParts...
Page 93: ...6 12 Replaceable Parts Model 2500 Service Manual...
Page 94: ...A Specifications...
Page 98: ...B CalibrationReference...
Page 108: ...C CalibrationProgram...
Page 117: ......
Page 119: ......
Page 120: ......
Page 121: ...Keithley Instruments Inc 28775 Aurora Road Cleveland Ohio 44139 Printed in the U S A...