Tektronix 7B85 Instruction Manual page 3

7885 Instruction
Section 3 THEORY OF OPERATION (cont)
Comparator (SN B088750 & Up) . 3-21
Comparator (SN 8088749 &
Trigger Generator . . . . . . . . . . . . . . . . 3-6
Below) . . . . . . . . . . . . . . . . . . . . . . 3-21
External Source . . . . . . . . . . . . . . . 3-6
Ramp Control . . . . . . . . . . . . . . . . 3-21
Internal and Line Source . . . . . . . . 3-6
Divide by 4 Counter . . . . . . . . . . . . 3-21
Trigger Source Selector and
Timer . . . . . . . . . . . . . . . . . . . . . . . 3-21
Amplifier . . . . . . . . . . . . . . . . . . . . . 3-6
Reference Current Source
Peak-to-Peak Auto . . . . . . . . . . . . 3-8
(SN ~088750 & Up) . . . . . . . . . . . . 3-22
Slope Selector and Trigger
Reference Current Source
Generator . . . . . . . . . . . . . . . . . . . . 3-8
(SN ~088749 & Below) . . . . . . . . . 3-22
Gate Generator . . . . . . . . . . . . . . . 3-9
Reference Current Inverter
Logic . . . . . . . . . . . . . . . . . . . ~ ~ ~ ~ ~ ~ . 3-10
(SN ~088750 & Up) . . . . . . . . . . . . 3-22
Sweep Modes . . . . . . . . . . . . . . . . 3-10
Reference Current Inverter
Hold Off Timing . . . . . . . . . . . . . . . 3-11
(SN B088749 & Below) . . . . . . . . . 3-22
Lockout Buffer Amplifier . . . . . . . . 3-11
Reference Current Switch . . . . . . . 3-22
Hold Off Generator . . . . . . . . . . . . 3-11
Counter and Encoder
Hold Off Output Amplifier . . . . . . . 3-11
(SN B088"750 & Up) . . . . . . . . . . . . 3-22
Delay Pickoff Inhibit . . . . . . . . . . . . 3-12
Counter and Encoder
Delay Mode Control . . . . . . . . . . . . 3-12
(SN ~088749 & Below) . . . . . . . . . 3-22
Auxiliary Y-Axis Generator . . . . . . 3-12
Counter Transfer Control . . . . . . . . 3-23
Sweep Generator . . . . . . . . . . . . . . . . 3-13
Zero Count Correction . . . . . . . . . . 3-23
Timing Current Source . . . . . . . . . . 3-13
Time/Division and Readout
Ramp Generator . . . . . . . . . . . . . . 3-13
Switching . . . . . . . . . . . . . . . . . . . . . . 3-23
Output Preamplifier . . . . . . . . . . . . 3-13
Basic Readout System . . . . . . . . . 3-23
Sweep Gate Generator . . . . . . . . . 3-16
Time/Division and Readout . . . . . . 3-23
Pickoff Amplifiers and Delay
Delay Time Readout . . . . . . . . . . . 3-23
Gate Generator. . . . . . . . . . . . . . . . . . 3-16
Interface Connectors and Power
Delay Time Comparison
Supply . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
(SN B088750 & Up) . . . . . . . . . . . . 3-16
Delay 'time Comparison
(SN ~088749 & Below) . . . . . . . . . 3-16
O 'Time Comparison
(SN ~088750 & Up) . . . . . . . . . . . . 3-16
Time Comparison
Section
4 MAINTENANCE
(SN ~088749 & Below) . . . . . . . . . 3-18
Delay Bias and Second Delay
Preventive Maintenance . . . . . . . . . . . . . 4-1
Pickoff Clamp. . . . . . . . . . . . . . . . . 3-18
Cleaning . . . . . . . . . . . . . . . . . . . . . . . 4-1
Delay Comparison Voltage
Exterior . . . . . . . . . . . . . . . . . . . . . 4-1
Switch . . . . . . . . . . . . . . . . - . . . . . 3-18
Interior . . . . . . . . . . . . . . . . . . . . . . 4-1
Delay Gate Generator . . . . . . . . . . 3-18
Switch Contacts . . . . . . . . . . . . . . 4-1
Symbol Enable . . . . . . . . . . . . . . : 3-19
Visual Inspection . . . . . . . . . . . . . . . . 4-1
Digital Voltmeter . . . . . . . . . . . . . . . . . 3-19
Lubrication . . . . . . . . . . . . . . . . . . . . . 4-2
Delay Comparison Voltage to Ramp
Cam Switch Lubrication . . . . . . . . . 4-2
Converter (SN ~088750 & Up) . . . 3-20
Semiconductor Checks . . . . . . . . . . . . 4-2
Delay Comparison Voltage to Ramp
Adjustment After Repair . . . . . . . . . . . 4-2
Converter (SN ~088749 & Below) 3-21
Troubleshooting . . . . . . . . . . . . . . . . . 4-3
ii
REV AUG 1981
(cont)