Atec Tektronix-1502 User Manual
Page 58
TM 9-4935-601-14-3&P
Visual Inspection
Prior to recalibration, the 1502 should be inspected for such defects as broken connections, damaged
circuit boards, improperly seated pin connectors, frayed cable shields and heat-damaged components.
The corrective procedures for most visible defects are obvious; however, particular care should be taken if
heat damaged components are found. Overheating usually indicates other trouble in the instrument; therefore,
it is important that the cause of overheating be corrected to prevent recurrence of the damage.
In order to maintain the water-tight integrity of the 1502, it is important to visually inspect the water-tight
seals periodically. Seals around the X-Y Output Module, the battery pack and the front cover seal on the front
panel should be checked regularly to see that they have not become damaged. The clam shell seal on the
back of the front-panel casting and the seals around the front-panel controls and connectors should be
inspected when the cabinet has been removed for maintenance, calibration purposes, or if a leak is suspected.
CAUTION
Anytime the cabinet has been removed from the 1502 or when any front panel
controls or connectors have been removed from the front panel, the water-tight
integrity of the 1502 will be jeopardized.
Semiconductor Checks
Periodic checks of the semiconductors in the 1502 are not recommended. The best check of
semiconductor performance is actual operation in the instrument. More details on checking semiconductor
operation are given under troubleshooting.
Recalibration
To ensure accurate measurements, check the calibration of the 1502 after each 1000 hours of operation or
every six months if used infrequently. In addition, replacement of components may necessitate recalibration of
the affected circuits. The calibration procedure can also be helpful in localizing certain troubles in the
instrument. In some cases, problems may be revealed or corrected by recalibration.
Servicing the Battery
The battery pack should be inspected every six months or every 500 hours of operation, whichever occurs
first. The entire battery pack should be replaced if venting or corrosion has occurred.
TROUBLESHOOTING
The following information is provided to help in troubleshooting the 1502. Information contained in other
sections of this manual should be used along with the following information to aid in locating the defective
component(s). An understanding of the circuit operation is helpful in locating troubles. See the Circuit
Description section for information.
Troubleshooting Aids
Diagrams. Circuit diagrams and corresponding circuit board layouts are located on foldout pages at the
rear of the manual. Section 7 contains the Electrical Parts List. From these schematics and parts lists, the
component number, location, electrical characteristics and Tektronix, Inc. part number can be cross-
referenced. The components that are located on the front panel are shown on the circuit diagrams with their
front-panel titles enclosed in a block. Additional aids for troubleshooting can be found in the Calibration section
of this manual.
COMPONENT REMOVAL AND REPLACEMENT
Fuses
The ac line fuses are located on the front panel. The dc fuses and spares are located on the Power Supply
board inside the instrument. Remove the 1502 from its case. Remove the aluminum shield from the top of the
unit. The fuses are upright plug-in types located near the center of the instrument (see Fig. 5-1).
Transistors and Integrated Circuits
Circuit Board Replacement
Most of the components mounted on the circuit boards can be replaced without removing the boards from
the instrument. An exception is the HV circuit board which is located underneath the Power Supply board. If a
circuit board is damaged beyond repair, the entire assembly (including all soldered-on-components) can be
replaced. The number is given in the Electrical Parts list for the completely wired board.
Use the following procedure to remove a circuit board. Reverse the procedure to replace boards.
REV B FEB 1980
5-2