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

Basic Maintenance: Parts Replacement and Substitution
- Make skin contact with a conductive work surface first and maintain this contact when the
device is set down or picked up.
7. Always wear a conductive wrist strap when servicing this equipment. The Motorola part num-
ber for a replacement wrist strap that connects to the table mat is 42-80385A59.
8. When straightening CMOS pins, provide ground straps for apparatus used.
9. When soldering, use a grounded soldering iron.

Parts Replacement and Substitution

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.

Rigid Circuit Boards

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.

Specific

During all repair procedures, heating neighboring 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.
!
C a u t i o n
68P81083C20-D
If neighboring OMPAC components are heated above 365
degrees F or 185 degrees C they will suffer die-bond
delamination and possible "popcorn" failure.
2-3
December 6, 2004