Before attempting any repair or detailed tuning, shield the device from RF noise or static
electricity discharges.
Use only demagnetized tools that are specifically designed for small electronic repairs,
as most electronic parts are sensitive to electromagnetic forces.
Use only high quality screwdrivers when servicing products. Low quality screwdrivers can
easily damage the heads of screws.
Use only conductor wire of the properly gauge and insulation for low resistance, because of the low margin
of error of most testing equipment.
We recommend 22-gauge twisted copper wire.
Hand-soldering is not recommended, because printed circuit boards (PCBs) can be easily
damaged, even with relatively low heat. Never use a soldering iron with a power rating of
more than 100 watts and use only lead-free solder with a melting point below 250°C (482°F).
Prior to disassembling the battery charger for repair, ensure that the AC power is disconnected.
Always use the replacement parts that are registered in the SEC system. Third-party replacement parts
may not function properly.
Many semiconductors and ESDs in electronic devices are particularly sensitive to static discharge and can
be easily damaged by it. We recommend protecting these components with conductive anti-static bags
when you store or transport them.
Always use an anti-static strap or wristband and remove electrostatic buildup or dissipate
static electricity from your body before repairing ESDs.
Ensure that soldering irons have AC adapter with ground wires and that the ground wires are properly
connected.
Use only desoldering tools with plastic tips to prevent static discharge.
Properly shield the work environment from accidental electrostatic discharge before opening
packages containing ESDs.
The potential for static electricity discharge may be increased in low humidity environments,
such as air-conditioned rooms. Increase the airflow to the working area to decrease the
chance of accidental static electricity discharges.
2. Specification
2-1. GSM General Specification
Uplink/Downlink
869~894
925~960
1805~1880
1930~1990
Bit Period
3.692us
3.692us
3.692us
3.692us
4.615ms
4.615ms
EGPRS
8PSK
8PSK
8PSK
8PSK
E2(8PSK)
E2(8PSK)
E2(8PSK)
E2(8PSK)
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ItemGSM 850EGSM 900DCS1800PCS1900
Freq. Band[MHz]
ARFCN range 128~251 0~124 & 975~1023 512~885 512~810