Parts Replacement And Substitution; Rigid Circuit Boards; Specific - Motorola MCS 2000 Service Instructions Manual

Parts
Replacement
and
Substitution
Rigid Circuit
Boards
Specific
!
C a u t i o n
18. Always wear a conductive wrist strap when servicing this equipment.
The Motorola part number for a replacement wrist strap that connects to
the table mat is 42-80385A59.
19. When straightening CMOS pins, provide ground straps for apparatus used.
20. When soldering, use a grounded soldering iron.
Special care should be taken to be as certain as possible that a suspected
component is actually the one at fault. This special care will eliminate
unnecessary unsoldering and removal of parts, which could damage or
weaken other components or the printed circuit board itself.
When damaged parts are replaced, identical parts should be used. If the
identical replacement component is not locally available, check the parts list
for the proper Motorola part number and order the component from the
nearest Motorola Communications Parts office.
This family of radios uses bonded, multi-layer, printed circuit boards. Since the
inner layers are not accessible, some special considerations are required when
soldering and unsoldering components. The printed-through holes may
interconnect multiple layers of the printed circuit. Therefore, care should be
exercised to avoid pulling the plated circuit out of the hole.
When soldering near the module socket pins, use care to avoid accidentally
getting solder in the socket. Also, be careful not to form solder bridges between
the module socket pins. Closely examine your work for shorts due to solder
bridges. When removing modules with metal enclosures, be sure to desolder
the enclosure ground tabs as well as the module pins.
During all repair procedures, heating neighbouring components can be
minimized by:
• using upper heat only.
• using the correct size heat focus head approximately the same size as the
carrier being replaced
• keeping the heat focus head approximately1/8" or 3-6 mm above the
printed circuit board when removing or replacing the device.
If neighbouring OMPAC components are heated above 365 degrees F or
185 degrees C they will suffer die-bond delamination and possible
"popcorn" failure.
Basic Maintenance 2-3