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When the customer’s telephone line corresponds to the following conditions, and the transmission signal of SP-Phone is inter-
rupted, performing the next set up to a cordless handset will improve it to some extent.
Conditions

1. When customer’s line has less line loss.

ex.) The customer is using optical fiber, ISDN terminal adaptor, or PBX.
In this case, receiving signal is strong and it may affect transmission signal.

2. When the other party is talking from noisy place.

ex.) The other party is using cellular phone. The background noise is very loud.
In this case, the noise from the other party (i.e. surrounding noise) may affect transmission signal.

• Change the handset address of EEPROM (0129) from 00 to 01 by Engineering Mode.

(N)* Power RAMP Confirma-

tion

-

Follow steps 1 to 3 of (I).

4.Confirm that Power RAMP is matching.

IC1, 

C808~C814, 

L802~L804, 

C825, C834, 

C819, IC801, 

R107, R108, 

C117, C118, 

C841, C125, 

C842, DA1, 

C801~C804, 

D801,D802, 

C837, C826, 
C822, C820, 
C832, C833, 

R801~R807

(O) Audio Check and Confir-

mation

-

1. Link to BASE which is connected to Line Simulator.
2. Set line voltage to 48 V and line current to 40 mA.
3. Input -45 dBm/1KHz to MIC and measure Line output level.
4. Confirm that the level is -10 dBm ± 2 dBm and that the distortion level is < 5%

at TEL Line (600 

Ω Load).

5. Input -20 dBm/1KHz to Line I/F and measure Receiving level at REV+ and

REV-.

6. Confirm that the level is -21 dBm ± 2 dBm and that the distortion level is < 5%

at Receiver. (vol = 2)

IC1, R23, C12, 

D19, D20, 
C96, C97, 

R215, R27, 

RA4, C11, 

C13, R28, D3, 

D4, L10, L11, 

MIC

(P) SP phone Audio Check 

and Confirmation

-

1. Link to Base which is connected to Line Simulator.
2. Set line voltage to 48 V and line current to 40 mA.
3. Set the handset off-hook using SP-Phone key.
4. Input -25 dBm/1KHz to Line I/F and measure Receiving level at SP+ and SP-.
5. Confirm that the level is -15 dBm ± 2 dBm and that the distortion level is < 5%.

(vol = 3)

IC1, R23, C12, 

C73, D13, 

D14, R152, 

C80, L10, L11, 

MIC, C11, 

C13, RA4, 

R27, R28, 
C96, C97, 

R215, C72

(Q) Charge Pump 2.5V Sup-

ply Confirmation

CP2.5V

1. Confirm that the voltage between testpoint and CP2.5V and GND is 2.5V -0.1/

+0.3V.

C52, C53, C49

Items

Check 

Point

Procedure

Check or 

Replace Parts

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Even if you do not have the special tools (for example, a spot heater) to remove the Flat IC, with some solder (large amount), a
soldering iron and a cutter knife, you can easily remove the ICs that have more than 100 pins.

• PbF (: Pb free) Solder
• Soldering Iron

Tip Temperature of 700 

°F ± 20 °F (370 °C ± 10 °C)

Note: We recommend a 30 to 40 Watt soldering iron. An expert may be able to use a 60 to 80 Watt iron where someone with
less experience could overheat and damage the PCB foil.

• Flux

Recommended Flux: Specific Gravity 

→ 0.82.

Type 

→ RMA (lower residue, non-cleaning type)

Note: See About Lead Free Solder (Pbf: Pb free) (P.4)

1. Put plenty of solder on the IC pins so that the pins can be completely covered.

If the IC pins are not soldered enough, you may give pressure to the P.C. board when cutting the pins with a cutter.

2. Make a few cuts into the joint (between the IC and its pins) first and then cut off the pins thoroughly.

3. While the solder melts, remove it together with the IC pins.

When you attach a new IC to the board, remove all solder left on the board with some tools like a soldering wire. If some solder is
left at the joint on the board, the new IC will not be attached properly.

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1. Temporarily fix the FLAT PACKAGE IC, soldering the two marked pins.

*Check the accuracy of the IC setting with the corresponding soldering foil.

2. Apply flux to all pins of the FLAT PACKAGE IC.

3. Solder the pins, sliding the soldering iron in the direction of the arrow.

1. Lightly resolder the bridged portion.
2. Remove the remaining solder along the pins using a soldering iron as shown in the figure below.

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• PbF (: Pb free) Solder
• Soldering Iron

Tip Temperature of 700

°F ± 20°F (370°C ± 10°C)

Note:
We recommend a 30 to 40 Watt soldering iron. An expert may be able to use a 60 to 80 Watt iron where someone with less 
experience could overheat and damage the PCB foil.

• Hot Air Desoldering Tool

Temperature: 608

°F ± 68°F (320°C ± 20°C)

• To replace the IC efficiently, choose the right sized nozzle of the hot air desoldering tool that matches the IC package.
• Be careful about the temperature of the hot air desoldering tool not to damage the PCB and/or IC.

1. Heat the IC with a hot air desoldering tool through the P.C.Board.

2. Pick up the IC with tweezers, etc. when the solder is melted completely.

• Be careful not to touch the peripheral parts with tweezers, etc. They are unstable. 

When it is hard to melt the solder completely, heat it with a hot air desoldering tool through the IC besides through the
P.C.Board.

3. After removing the IC, clean the P.C.Board of residual solder.