Service Manual

MM-E 2072-09333-00
3-2
f. Micom-Z modules make extensive use of surface-mounted (SMT) components and
miniaturization, therefore personnel involved in troubleshooting and repair must be thoroughly
familiar with the applicable workmanship procedures. No special tools are needed for repair,
except for a standard technician’s toolbox and a soldering/desoldering station with an
appropriate set of tips, considering the component types used in the module (in particular multi-
lead and SMT components). Use standard workmanship practice for repair and component
replacement procedures:
• Pay special attention to avoid overheating or damage to adjacent components. Use only a
soldering tool with a temperature-controlled tip, and minimize heating time.
• Pay attention to the orientation of polarized components.
• During soldering of RF transistors, use minimum solder and make sure that the solder does
not flow to other areas.
Clean the module after any repair, and thoroughly remove any remaining foreign matter, in
particular solder remnants. Inspect visually after repairs are completed.
g. Whenever a cover or a PCB is fastened by multiple screws, first insert all the screws and tighten
them by hand, and then use a screwdriver, to tighten completely the screws. Tighten the screws
alternately, starting with the screws at the opposite ends of one diagonal, then those at the ends
of the other diagonal. Do not tighten one screw completely and then the others: take up one turn
at a time for each screw, sequentially, in the order described.
Avoid exerting excessive torque when tightening screws. Table 3-1 provides standard tightening
torques for screws (the allowed torque tolerance is ±10%).
Table 3-1. Tightening Torques for Screws
Screw Size
Thread Forming
Metallic Surface
Threaded Metallic
Surface
Plastic
Surface
Metric System Screws
M3 10 kgf/cm 10 kgf/cm 6 kgf/cm
M4 15 kgf/cm 15 kgf/cm 7 kgf/cm
M5, M6 22 kgf/cm 18 kgf/cm 8 kgf/cm
American System Screws
4-40 10 kgf/cm 7 kgf/cm 6 kgf/cm
6-32 15 kgf/cm 15 kgf/cm 7 kgf/cm
8-32, 10-32 22 kgf/cm 18 kgf/cm 8 kgf/cm