Sony IT-B1 User manual

1
SERVICE MANUAL
SPECIFICATIONS
Dial signal Tone, 10 PPS (pulse) selectable
Dimensions Approx. 69 ×74.5 ×225 mm (w/h/d)
(Approx. 2 3/4 ×3 ×8 7/8 inches)
Mass Approx. 485 g
(Approx. 17 oz), attachments included
Supplied accessories • Telephone line cords (2)
• Handset cord
Design and specifications are subject to change without notice.
IT-B1
Canadian Model
Central & South America Model
TELEPHONE
MICROFILM
Notes on Chip Component Replacement
•Never reuse a disconnected chip component.
•Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.
Photo: WHITE Type

55
IT-B1
3-2. SCHEMATIC DIAGRAM — HANDSET SECTION — • Refer to page 7 for IC Block Diagrams.
Note:
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in Ωand 1/4W or less unless otherwise
specified.
• % : indicates tolerance.
•¢: internal component.
•C: panel designation.
•U: B+ Line.
• Connect J2 and J3 with handset cord.
Power voltage is dc 12V and fed with regulated dc power
supply from J3 with 100 Ωin series.
• Voltage is dc with respect to ground under no-signal
condition.
no mark : OFF HOOK
( ) : ON HOOK
• Voltages aretaken withaVOM(Inputimpedance 10MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Signal path.
N: RX (fromTEL LINE)
O:TX (to TEL LINE)
P: bell
• Abbreviation
MX : Mexican model
LA : Latin American model

66
3-4. SCHEMATIC DIAGRAM — CRADLE SECTION —
IT-B1
3-3. PRINTED WIRING BOARD — CRADLE SECTION —
Note:
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
• All resistors are in Ωand 1/4W or less unless otherwise
specified.
• % : indicates tolerance.
•¢: internal component.
•C: panel designation.
•U: B+ Line.
• Power voltage is dc 12V and fed with regulated dc power
supply from J3 with 100 Ωin series.
• Voltage is dc with respect to ground under no-signal
condition.
no mark : OFF HOOK
( ) : ON HOOK
• Voltages aretakenwith aVOM(Input impedance10 MΩ).
Voltage variations may be noted due to normal produc-
tion tolerances.
• Signal path.
N: RX (fromTEL LINE)
O:TX (to TEL LINE)
P: bell
Note:
•X: parts extracted from the component side.
•¢: internal component.
•b: Pattern from the side which enables seeing.
(The other layer’s patterns are not indicated.)
D33 D-2
D34 D-1
IC1 B-2
ZD1 B-1
D1 A-3
D2 A-3
D3 A-3
D4 B-3
D5 B-1
D31 C-2
D32 C-1
• Semiconductor Location
Ref. No. Location Ref. No. Location
JW

7
• IC Block Diagrams
IC2 TEA1112AT
IC3 HM91510AP
CURRENT
REFERENCE
LOW
VOLTAGE
CIRCUIT
LED
DRIVER ATT
MICRO
MUTE
AGC
CIRCUIT
16
VCC
1
LN 2 SLPE 3 LED 4 REG 5 GAS 6 MMUTE 7 OTMF 8 MUTE
GAR QR VEE MIC+ MIC- IRAGC
15 14 13 12 11 910
ROW
INTERFACE CIRCUIT
COLUMN
INTERFACE CIRCUIT DIVIDER
OSC
KERNEL CONTROL CIRCUIT
INPUT
INTERFACE
CIRCUIT
OUTPUT
INTERFACE
CIRCUIT
ROW/COLUMN
PROGRAMMING
COUNTER
D/A
CONVERTER
DECODER
&
DATA LATCH
PULSE
GENERATOR
LNB
MEMORY
1
C1 2 C2 3 C3 4 C4
VSS
VDD
5
KT 6 OSCI 7 OSCO 8 XMUTE 9 VSS
18
R4 17 R3 16 R2 15 R1 14 MODE 1213 TONE 10 VDD
11
HKSPO
MEMORY
VDD