Specifications

Model 75A250A Manual Text
4-1
REV A
SECTION IV
MAINTENANCE
4.1 GENERAL MAINTENANCE INFORMATION
The Model 75A250A should require very little maintenance since it is a relatively simple instrument. It is built with
etched circuit wiring and solid state devices which should ensure long, trouble-free life. However, should trouble
occur special care must be taken in servicing to avoid damage to the devices or the etched circuit board.
Since the components are soldered in place, substitution of components should not be resorted to unless there is
some indication that they are faulty. In addition, take care when troubleshooting not to short voltages across the
amplifier. Small bias changed may ruin the amplifier due to excessive dissipation or transients.
Components with Amplifier Research instruments are conservatively operated to provide maximum instrument
reliability. In spite of this, parts within an instrument may fail. Usually, the instrument must be immediately repaired
with a minimum of "down time". A systematic approach can greatly simplify and thereby speed up the repair.
However, due to the importance of the amplifier's alignment, it is recommended that when failure is caused by
breakdown of any of the components in the signal circuits, the amplifier be returned to the factory for part
replacement and amplifier realignment. Shipping instructions are as follows:
Ship PREPAID via United Parcel Service to: AMPLIFIER RESEARCH
160 SCHOOL HOUSE ROAD
SOUDERTON, PA 18964
See warranty statement at rear of manual.
4.2 COVER AND CIRCUIT BOARD REMOVAL
CAUTION:
REMOVE POWER CORD FROM RECEPTACLE BEFORE SERVICING.
4.2.1 The amplifier can be removed from the housing by removing 4 screws from the front panel and 4 screws
from the back panel. The amplifier can then be slid from the housing.
4.2.2 The top cover can be removed to gain access to the RF assembly. The bottom cover can be removed to
gain access to the power supply assembly..