ICs and LSIs are vulnerable to static electricity.
When repairing, the following precautions will help prevent recurring malfunctions.
1. Cover the plastic parts boxes with aluminum foil and ground them.
2. Ground the soldering irons.
3. Use a conductive mat on the worktable.
4. Do not touch IC or LSI pins with bare fingers.
2Warning
2.1.Battery Caution
1. Danger of explosion if battery is incorrectly replaced.
2. Replace only with the same or equivalent type recommended by the manufacturer.
3. Dispose of used batteries according to the manufacture’s Instructions.
2.2.About Lead Free Solder (Pbf: Pb free)
Note:
In the information below, Pb, the symbol for lead in the periodic table of elements, will refer to standard solder or solder that contains lead.
We will use PbF solder when discussing the lead free solder used in our manufacturing process which is made from Tin (Sn),
Silver (Ag), and Copper (Cu).
This model, and others like it, manufactured using lead free solder will have PbF stamped on the PCB. For service and repair
work we suggest using the same type of solder.
Caution
• PbF solder has a melting point that is 50 °F ~ 70 °F (30 °C ~ 40 °C) higher than Pb solder. Please use a soldering iron with
temperature control and adjust it to 700 °F ± 20 °F (370 °C ± 10 °C).
• Exercise care while using higher temperature soldering irons.:
Do not heat the PCB for too long time in order to prevent solder splash or damage to the PCB.
• PbF solder will tend to splash if it is heated much higher than its melting point, approximately 1100 °F (600 °C).
• When applying PbF solder to double layered boards, please check the component side for excess which may flow onto the
opposite side (See the figure below).
There are several types of PbF solder available commercially. While this product is manufactured using Tin, Silver, and Copper
(Sn+Ag+Cu), you can also use Tin and Copper (Sn+Cu) or Tin, Zinc, and Bismuth (Sn+Zn+Bi). Please check the manufacturer’s
specific instructions for the melting points of their products and any precautions for using their product with other materials.
The following lead free (PbF) solder wire sizes are recommended for service of this product: 0.3 mm, 0.6 mm and 1.0 mm.
2.2.2.How to Recognize that Pb Free Solder is Used
(Example: Handset P.C.B.)
Marke
> EP-GW <
35-006057-005-200
RF
U4
U3
(Component View)
Note:
The location of the “PbF” mark is subject to change without notice.
The base-station consists of base band controller, speech network, tel-line interface, RF module, linear regulator, EEPROM,
crystal and so on. Refer to Block Diagram (Base Unit) (P.7).
4.2.1.Base Band Controller
These are parts to control all function of the base-station, we used the Philips XS which is controller for DECT. These devices
include all control circuits of the base-station for RF module, tel-line interface, ADPCM codec, series regulator and so on.
4.2.2.Power Supply
The power supply consists with CM1117 voltage regulator ICs.
CM1117 generate DC 3.3V voltage from DC 6V voltage from adaptor. DC 3.3V are used for RF module & I/O port, DC 2.5V &
DC1.8V are used for the base band controller and the circumference circuits.
4.2.3.Speech Network
The TR circuit is used for speech network. The function of this connects tel-line interface and the base band controller.
4.2.4.TEL Line Interface
The function of this connects tel-line and speech network. Also, the tel-line interface include the ring detect circuit, caller-ID circuit.
4.2.5.EEPROM
This is 8K bits memory. The each kind of value to set-up at power-on, redial memory, speed-dialing memory, and so on are
stored in this device.
4.2.6.RF Module
Receiver part: RF signals induced at the antenna are extracted by the RF control interface. The RF signal to be selected is
demodulated into RX_DATA signals. And signals is passed to the base band controller.
Transmitter part: The signal from transceiver chip-set is fed to the antenna through the RF power amplifier by control of the RF
control interface. And then this signal is radiated from antenna.
Logical part: The frequency to be used is generated in transceiver chip-set by control signals (CLK, DATA, ENABLE, SYRI) of
the RF control interface.
4.2.7.Current Limiter
The current limiter is circuit to supply the proper current to charge batteries of the handset from DC 6V voltage.
The handset consists of Base Band Controller, LCD, RF module, keypad, regulator, charger, EEPROM, crystal, earpiece, ringer
& microphone, and so on.
4.4.1.Base Band Controller
The base band controller controls all function of the handset, Philips XS for the base band controller is used.
This device include all control circuits of the handset for RF module, LCD controller, keypad interface, earpiece, microphone,
ADPCM codec, switching and series regulator and so on.
4.4.2.Charger
The base-station supply DC 6V power to the charger and the charger charges the batteries to use this power. The signal on the
charger circuit is generated when the handset is to being charged this signal is used to control the charger circuit and for auto-
matic off-hook by cradle-off when an incoming call is coming.
4.4.3.2.4V 2 cell & 3.3V output from internal switching regulator
The battery is (2.4V / 2cell) directly supplied to switching regulator which controlling by base band controller and step up the DC
3.3V to the RF module & I/O port. DC 2.5V & DC1.8V are used for the base band and the circumference circuits.
4.4.4.RF Module
Receiver part: RF signals induced at the antenna are extracted by the RF control interface. The RF signal to be selected is
demodulated into RX_DATA signals. And signals is passed to the base band controller.
Transmitter part: The signal from transceiver chip-set is fed to the antenna through the RF power amplifier by control of the RF
control interface. And then this signal is radiated from antenna.
Logical part: The frequency to be used is generated in transceiver chip-set by control signals (CLK, DATA, ENABLE, SYRI) of
the RF control interface.
4.4.5.LCD
The LCD consists of 7-segment, 12 digit display and 13 icon which controlling by the LCD display driver.
4.4.6.Keypad
The keypad consists of 12 dialing keys and 8 function keys.
Rx audio signal from line interface at “LINERX_P” path into B/S MCU (pin 32, 33) and then signal from B/S RF transform, H/S RF
receive signal forward to MCU, H/S MCU from (pin 32, 33) receive path output audio signal to receiver.
Tx audio signal from MIC receive audio signal at mic path into H/S MCU and then audio signal from H/S RF transform, B/S RF
receive signal forward to MCU, B/S MCU audio signal from (Pin 30, 29) at “LINETX_P” path transmit to line interface out of PSTN.
4.5.2.Ringer detect:
Telephone line have ringer signal from tip ring into Base, and then Base transistor Q8 turn on and ringer data signal for Base MCU
(Pin 58_IOGP16) detect and the handset buzzer have product “Melody tone”.
4.5.3.Type I CID receive:
CID signal from tip ring couple CID signal at (CID1_P, CID1_N) path into Base MCU (Pin 29, 30) detect, Handset display show the
telephone no.