Ritron RIT17-442 Manuale Utente
MAINTAINANCE
Surface Mount Repair
RITRON surface mount products require special equipment and servicing techniques. Improper servicing
techniques can cause permanent damage to the printed circuit boards and/or components, which is not covered
by RITRON’s warranty. If you are not completely familiar with surface mounted component repair techniques,
RITRON recommends that you defer maintenance to qualified service personnel.
Precautions for Handling CMOS Devices
This radio contains complementary metal-oxide semiconductor (CMOS) devices, which require special handling
techniques. CMOS circuits are susceptible to damage by electrostatic or high voltage charges. Damage can be
latent, with no failure appearing until weeks or months later. For this reason, take special precautions any time
you disassemble the radio. Follow the precautions below, which are even more critical in low humidity
environments.
1) Storage/transport - CMOS devices that will be stored or transported must be placed in conductive material so
RITRON surface mount products require special equipment and servicing techniques. Improper servicing
techniques can cause permanent damage to the printed circuit boards and/or components, which is not covered
by RITRON’s warranty. If you are not completely familiar with surface mounted component repair techniques,
RITRON recommends that you defer maintenance to qualified service personnel.
Precautions for Handling CMOS Devices
This radio contains complementary metal-oxide semiconductor (CMOS) devices, which require special handling
techniques. CMOS circuits are susceptible to damage by electrostatic or high voltage charges. Damage can be
latent, with no failure appearing until weeks or months later. For this reason, take special precautions any time
you disassemble the radio. Follow the precautions below, which are even more critical in low humidity
environments.
1) Storage/transport - CMOS devices that will be stored or transported must be placed in conductive material so
that all exposed leads are shorted together. CMOS devices must not be inserted into conventional plastic
“snow” or plastic trays of the type that are used for other semiconductors.
“snow” or plastic trays of the type that are used for other semiconductors.
2) Grounding - All CMOS devices must be placed on a grounded bench surface. The technician that will work
on the radio/CMOS circuit must be grounded before handling the radio. Normally, the technician wears a
conductive wrist strap in series with a 100K Ohm resistor to ground.
conductive wrist strap in series with a 100K Ohm resistor to ground.
3) Clothing - Do not wear nylon clothing while handling CMOS circuits.
4) Power
4) Power
off - Remove power before connecting, removing or soldering a PC board that contains CMOS
devices.
5) Power/voltage
transients - Do not insert or remove CMOS devices with power applied. Check all power
supplies to be used for testing CMOS devices, making sure that no voltage transients are present.
6) Soldering - Use a grounded soldering iron for soldering CMOS circuitry.
7) Lead-straightening
7) Lead-straightening
tools - When straightening CMOS leads, provide ground straps for the tool used.
Synthesizer Shield
The synthesizer shield should not be removed, unless a component must be replaced. This shield is soldered to
the main PC board. The shild can be removed by sucking or wicking the solder up around the perimeter. If this
should prove difficult a side cutters can cut the top off after which the walls can be removed. A replacement shield
will then be needed.
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