Panasonic KX-TG8021BXS, Service Manual

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KX-TG8021BXS/KX-TG8021BXT/KX-TGA800BXS/KX-TGA800BXT
9.3.2. Troubleshooting for Speakerphone
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.
Setting Method
• Change the handset address of EEPROM (0129) from 00 to 01 by Engineering Mode .
( 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 -8.5 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 -22 dBm ± 2 dBm and that the distortion level is < 5%
at Receiver. (vol = 2)
IC1, R23, C12,
D21, D22,
C96, C97,
R27, RA4,
C11, C13,
R28, D3, D4,
R320, R321,
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 -14 dBm ± 2 dBm and that the distortion level is < 5%.
(vol = 3)
IC1, R23, C12,
C73, D13,
D14, R152,
C80, R320,
R321, MIC,
C11, C13,
RA4, R27,
R28, C72,
D3, D4
( Q ) Charge Pump 2.5V Sup-
ply Confirmation
CP2.5V 1. Confirm that the voltage between testpoint CP2.5V and GND is 2.5V -0.1/
+0.3V.
C52, C53, C49
Items Check
Point
Procedure Check or
Replace Parts