Toshiba 2857DD - Schematic Diagram (1;4); Signal Board Connections; PAL Comb;1 H DL Unit; Pro-Logic Unit Connections

SCHEMATIC DIAGRAM # MODEL: 2857DD
(1/4)
CAUTION: The international hazard symbols “A\” in the schematic diagram and the parts list designate components
which have special characteristics important for safety and should be replaced only with types identical to those
in the original circuit or specified in the parts list. The mounting position of replacements is to be identical with
originals. Before replacing any of these components, read carefully the PRODUCT SAFETY NOTICE on page 2. Do
not degrade the safety of the receiver through improper servicing.
SIGNAL BOARD 285'/DB PBS6GSSA
285 70D PBS6SSB
20570 “FPBSesae
9G]
58 ‘a, ‘B SOCKT
Hoot
TUNER
ALPS
SONY
MATSU
MATSU
285708 = RA _UFB128LX1
RB UFSt2BL
EGSESLX1
EG4ESLX1
$N23321196
‘$N23321162
‘$N23321162
$N23321162
TO POWER/DEF
285700
28570F
388Farsy
GJ21 SHORT
GJ22 SHORT
GJ31 OPEN
GJ32 OPEN
%
Ct) sti
GJ21 OPEN
GJ22 OPEN
GJ31 SHORT
GJ32 SHORT 0624
2SC1815Y
HR?
YS SW V-BLK
O
HOO2
A
IF/MPX MODUL.
285708 RA 0B-IMG MVGS4SA SN23148249
RB DB-IMB MVGS43 $N23148233
285700 ©: DD-IM9_ MVGS44
28570F__DN-IM10 MVOS45
SN23148235,
$N23148236
IF/MPX
.
3
SDAI/SCL1
coz |e
16V220,'
Relgucps
ReBuce)
COQAAE)
Rago-1
OBSERVATION
OF
VOLTAGES
AND
WAVEFORMS
NOTES:
1. Voltages read with VTVM from point shown to chassis ground, line voltage 220
volts, colour bar signal. Voltages reading may vary +20%.
Coe
sama
Kae
DOO
De) Na
ie) |
Vy
KAA ORK
PAL_M/N
Y_COMB
21PIN-R
5B ae SOCKT
a Le ‘SDAI/SCLI GS
St DET
S$ S2
FRONT AV
GND
L s2
R S2
21 PINR
<|
apne (oLzems |
ape fey zeme |
Oa
21PIN-Ys
SDA1,SCLI
SDAI.SCL1
Z|
Be al
S OUT
V-2
2. All waveforms are taken using a wide band oscilloscope and a low capacity probe.
3. Waveforms are taken using a standard colour bar signal. 3.05
4. Make sure that CONTRAST and COLOUR controls are in mid position and
BRIGHTNESS control is almost in maximum position. Set other controls for best
picture.
ie RE EN RTS PRO-LOGIC UNIT
Fd
Za,
=
°
5
Z
oS BEg 2h s 6
COOOO OOADADOOO
TEXT/RGB SW UNIT
Vy
—
IS)
Nay
iii AN, ie
2/|
| s+ ee:
| Ko
1. D.C. ‘resistance value of a principal t
gram. These are measured for separate
2. The circuits are subject to change with
: Solder links.
NC(DAC1)
) NC(2IPIM-Ys)
21PIN-B
i S
a —\)
Ve
IS "a
po) |