Panasonic KX-TG7120FXT, Service Manual

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KX-TG7120BXS/KX-TG7120BXT/KX-TGA711CXS/KX-TGA711CXT
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 address of EEPROM (0144) from 00 to 01.
( O ) Sensitivity Receiver
Confirmation
- Follow steps 1 to 3 of (K) .
4.Set DECT tester power to -88 dBm.
5.Confirm that the BER is < 1000 ppm.
IC1, IC4, C66,
C58, C57,
C50, C52,
C53,
R52, C60,
C61
( P ) Timing Confirmation - Follow steps 1 to 3 of (K) .
4.Confirm that the Timing accuracy is < ± 2.0 ppm.
IC1, IC4, C66,
C58, C57,
C50, C52,
C53,
R52, C60,
C61
( Q )* RSSI Level Confirmation - Follow steps 1 to 3 of (K) .
4.Set DECT tester power to -81 dBm.
5.Execute the command “readrssi“.
6.Confirm that the returned value is 1C ± 8 (hex).
7.Set DECT tester power to -63 dBm.
8.Execute the command “readrssi“.
9.Confirm that the returned value is 25 ± 8 (hex).
IC1, IC4, C66,
C58, C57,
C50, C52,
C53,
R52, C60,
C61
( R ) Power RAMP Confirma-
tion
- Follow steps 1 to 3 of (K) .
4.Confirm that Power RAMP is matching.
IC1, IC4, C66,
C58, C57,
C50, C52,
C53,
R52, C60,
C61
( S ) 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/1 KHz 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 -20dBm/1KHz to Line I/F and measure Receiving level at REV1 and
REV2.
6. Confirm that the level is -21 dBm ± 2 dBm and that the distortion level is < 5 %
at Receiver. (vol = 2)
IC1, R21, R22,
R23, R24,
R25, C11,
D4, D5, C12,
C73, C74,
C75, C95, C96
( T ) 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_TEST1
and SP_TEST2.
5. Confirm that the level is -14 dBm ± 2 dBm and that the distortion level is < 5 %.
(vol = 3)
IC1, R21, R22,
R23, R24,
R25, C11,
C39, C12,
C73, C74,
C75, C95, C96
Items Check
Point
Procedure Check or
Replace Parts