Block Diagram - Panasonic EASA-PHONE KX-T2355 Service Manual And Technical Manual

BLOCK DIAGRAM
IC2 PQVISC77655S IC3 PQVIIRSN34A
TRANSMIT CHANNEL
——
TRANSMIT
LEVEL
DETECTOR
TRANSMIT
ATTENUATOR.
TRANSMIT/
RECEIVE
ATTENUATOR :
DETECTOR CONTROL COMPARATOR
PEAK
LIMITER
SPEAKER ' RECEIVE
ATTENUATOR
—<$<_.
SIGNAL'
NOISE
RECEIVE
LEVEL
DETECTOR
AMP
ver ee Oe tee init Rg ——_—a
ADJUSTMENT
Loop Simulator
RC Oscillator
Please refer to Circuit Board and wiring Connection Diagram
which is located test points (¥).
Schematic Diagram of Loop Simulator
_ VARIABLE
- RESISTOR 4
. Set the unit's controls as follows:
A. SP-PHONE SWITCH—"'ON"
B. VOLUME CONTROL— "MAX"
2. Connect Test Points W-Y
resistance (fully counterclockwise).
Connect the unit to the loop simulator.
. Make adjustment in a quiet room. |
Transmission Level: .
a Set the loop simulator selector switch to "TX". |
2. Connect the RC Oscillator to Test Point ®(—)—W(+), and |
connect an electrolytic capacitor (50 V, 1 uF) as shown below. |
3. Set RC Oscillator to 1 kHz, —56 dBm. .
ut
: 1 kHz, —56 dBm 50 V 1 uF Vv
a ae Vv
4. Connect the VTVM to Test Points & (-) - W (+).
5. Adjust VR2 for a reading of —-23 dBm +0.5 dB on the VTVM.
>
oe on
If a 48 V OC power. supply is not available a
20 V OC power supply can be substituted.
However, ihe vanabie resistor (0O-5000
must de set to CG ohms.