3156B User Manual
Racal Instrument © 2005
Maintenance and Performance Checks 6-3
Repair and
Replacement
Repair and replacement of electrical and mechanical parts must be
accomplished with great care. Printed circuit boards can become
warped, cracked or burnt from excessive heat or mechanical stress.
The following repair techniques are suggested to avoid inadvertent
destruction or degradation of parts and assemblies:
1. Use a 60/40 solder and temperature-controlled 35 - 40 watt
pencil-type soldering iron on the circuit board. The tip of the iron
should be clean and properly tinned for best heat transfer to the
solder joint. A higher wattage soldering iron may separate the
circuit from the base material.
2. Keep the soldering iron in contact with the PC board for a
minimum time to avoid damage to the components or printed
conductors.
3. To desolder components, use a commercial "solder sucker" or a
solder-removing SOLDER - WICK, size 3.
4. Always replace a component with an exact duplicate as
specified in the parts list.
Performance
Checks
The following performance checks verify proper operation of the
instrument and should normally be used:
1. As a part of the incoming inspection of the instrument
specifications;
2. As part of the troubleshooting procedure;
3. After any repair or adjustment before returning the instrument to
regular service.
Environmental
Conditions
Tests should be performed under conditions of an ambient
temperature of 0
o
C to 37.7
o
C and at a relative humidity of less than
80%. If the instrument has been subjected to conditions outside these
ranges, allow at least one additional hour for the instrument to stabilize
before beginning the adjustment procedure.
