DOWNLOAD Panasonic KX-TS2350UAJ / KX-TS2350UAS / KX-TS2350UAT Service Manual ↓ Size: 1.2 MB | Pages: 29 in PDF or view online for FREE

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• Repair service shall be provided in accordance with repair technology information such as service manual so as to pre-

vent fires, injury or electric shock, which can be caused by improper repair work.

1. When repair services are provided, neither the products nor their parts or members shall be remodeled. 
2. If a lead wire assembly is supplied as a repair part, the lead wire assembly shall be replaced. 
3. FASTON terminals shall be plugged straight in and unplugged straight out. 

• ICs and LSIs are vulnerable to static electricity.

1. Cover plastic parts boxes with aluminum foil.
2. Ground the soldering irons.
3. Use a conductive mat on worktable.
4. Do not grasp IC or LSI pins with bare fingers.

In the information below, Pb, the symbol for lead in the periodic table of elements, will refer to standard solder or solder that con-
tains 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.

• 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).

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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 manufac
turer’s specific instructions for the melting points of their products and any precautions for using their product with other materi-
als. 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. 

When discarding P. C. Board, delete all personal information such as telephone directory and caller list or scrap P. C. Board.

• Specifications are subject to change without notice.

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MELODY

SEQUENCER

LINE ADAPTATION

POWER EXTRACTION

DC MASK

CONTROL

LOGIC

TONE

GENERATOR

RING

FREQUENCY

DISCRIMINATION

OSC

RAM

MUTE

DIALLER

LINE

CURRENT

SENSE

SOFT CLIP

AGC

V

DD

LI

CI

LS

RI

STB

A

GND

LED

V

DD

V

SS

MO

FCI

HS/DP

LLC

OSC

MFL

M

ODE

C1

C2

C3

C4

R1

R2

R3

R4

M2

M1

RO

CS

R9

sv1

AGND

3.58

ADL

RS

R

T

Q1

Q2

D23

R55

R103

S3

L

H

OFF

D24

R14

R2

C1

Q8

Q3

Ringer

D2

C34

D17

C22

HS Speake

r

HS MIC

R10

C5

C9

R5

R6

KX-TS2350  BLOCK DIAGRAM

R102

58

1

2

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When the hook switch SW1 is ON (off-hook), the circuit is closed, and current is supplied to the base of Q2 via the diode bridge
D17 and Q2 is On 

→ Q1 is ON (OFF-HOOK condition).

Q1 and Q2 are the dial pulse generating circuits, and are driven by the DIALER (IC1), when the DIALER Pin 10 of IC1 is LOW
→ Q2 is OFF and Q1 is OFF (break). If port Pin 10 is HIGH → Q2 is ON → Q1 is ON (make).

The tone dialing circuit consists of a DTMF (Dual Tone Multi Frequency) signal generator (outputted from Pin 25 of the IC1) for
tone dialing, and also a circuit for outputting the signal to line.
The DTMF circuit identifies inputs from the 12 keys (1, 2, 3, 4, 5, 6, 7, 8, 9, 0,   and #) by means of a total of seven frequencies,
that is four low frequencies (Low group) and three high frequencies (High group).

When a dial key is pressed, a DTMF signal is output from Pin 25 of IC1 as an analog synthetic wave.
The signal flow to the line is as follows.
Pin 25 of IC1 

→ Q3 → R9 → Q1 → Tel Line.

The DTMF signal is sent to the line via the following path. Q3 is an amplifier which is used to output the signal to line.
Shown below is the signal flow used to output the DTMF signal from the handset as a monitor tone when a dial key is pressed.
Pin 3 of IC1 

→ VR1 → C15 → Handset Speaker.

The signal combination and frequency corresponding to each dial key is shown on the next page.