Philips MC-20 Service Manual page 20

COMBI BOARD (Part 3) - CIRCUIT DIAGRAM
0250 G11 2250 E6 2254 E11 2258 G5 2262 D15 2266 B15 3251 A8
1250 D2 2251 D8 2255 F11 2259 G5 2263 C18 2267 E6 3252 H5
1251 E3 2252 D11 2256 A6 2260 H7 2264 C15 2268 F12 3253 H5
1252 I3 2253 E8 2257 B7 2261 B14 2265 D19 3250 A6 3254 H7
1 2 3 4
COMBI BOARD
Supply part
A
B
C 7.9V ac
8.3V ac
8V ac
MC20
T250
D
*
6250
1N4003
*
1250 * *
6251
1251
1
15.7V ac 1
T251
11.6V ac 1N4003
2 *
16V ac
11.8V ac 9253
2
16.5V ac 3
E 12.2V ac
*
3 6252
4
EH-B 1N4003
EH-B
*
6253
T252
1N4003
15.8V ac
F
16.6V ac
T253
16.1V ac
MC10
G
H
I 1252
T257
1
T258
to 2
+C
Low Power Standby (L.P.S.)
T259
3
Transformer
T260
4
STANDBY
J * EH-B
Item
1250 1251 2250 2255 2256 2257
Model
3M3
MC10 4M7
25V
16V
K
MC20
22u 10u
Item
6250 6252 6256 6258 6263
3264 3282 3283 3284 4250
6251 6253 6257 6262 6264
Model
L
MC10
1N4003 1N4003
MC20
1K 2K2 2K2 2K2
1 2 3 4
PCS 104 568
7-3
3255 B14 3259 C15 3263 D14 3267 F17 3271 H14 3275 H15 3279 J19 3283 C17
3256 B14 3260 C16 3264 C19 3268 F17 3272 I14 3276 J17 3280 K19 3284 C17
3257 B15 3261 D16 3265 E16 3269 G16 3273 I14 3277 K17 3281 C17 4250 B19
3258 B15 3262 C17 3266 F17 3270 I12 3274 K15 3278 J18 3282 C17 6250 D4
5 6 7 8 9
* * * *
2256
3250 6266 3251
470R 2K2
22u 1N4148
* MC20
*
2257 6268
10u BZX79-F8V2 -8.2V -8.2V
*
6267
1N4148
13V
MC20
13.7V
9.2V
10.6V 9.8V
*
*
9251
2251 6254 6255 6256
+AMP
100n 1N4003
1N4003 1N4003
15V
T254
+B
* *
*
2250 2267 2253 6260 6261 6262
3m3
4m7 100n
1N4003 1N4003 1N4003
T256
2258 2259
4u7
4u7
Recognition
6269
Mains Breakdown
6.2V
6.2V
1N4148
6270 6.2V
3254
PWRDWN
1N4148 2K2
3252 3253 6271
2260
4K7 4K7 47n
BZX79-F6V8
2261 2263 2264 2265 2266 2267 2268 3250 3251
2u2 47u 47u
3M3 4M7
4u7 100u 100n 470 2K2
16V 25V
6266
6268 7253 9251 9252 9253
6267
1N4003 1N4003 1N4003 1N4148 BZX79-F8V2 BC368
5 6 7 8 9
6251 D4 6255 D8 6259 D10 6263 E10 6267 B7 6271 H8 6275 J17 7253 C19
6252 E4 6256 D9 6260 E8 6264 E10 6268 B8 6272 B16 7250 A14 7254 E17
6253 E4 6257 D10 6261 E8 6265 E10 6269 G6 6273 E18 7251 C14 7255 G17
6254 D8 6258 D10 6262 E9 6266 A7 6270 H6 6274 I12 7252 C16 7256 H16
10 11 12 13
17.7V
18.4V
-8V2 +A
21V
*
2261
-8.2V
(MC20)
3255
1K
*
3263
STANDBY
1K
* *
6257 6258 6259 2252
MC20
19V
100n
1N4003
1N4003 1N4003
19.4V 18.8V
21.7V 19.8V
21V
T255
+A
* *
6263 6265
6264 2254
1N4003 100n
1N4003 * *
1N4003
2255 2268
3m3 4m7
PAD
P_GND D_GND A_GND
0250
to
BOTTOM
PLATE
+C
3271
4R7
(no L.P.S.)
3272
9255
+B
4R7
3270
6274
3273
1N4003
3R3
4R7
(L.P.S.) (L.P.S.)
3263
1K
4K7
10 11 12 13
7-3
7257 I15 7261 K19 9254 E18 T251 E2 T255 E12 T259 I4 T263 I19
7258 I14 9251 D6 9255 I12 T252 F2 T256 F6 T260 J4 T264 J19
7259 J15 9252 B19 9256 E16 T253 F3 T257 I4 T261 A19
7260 J18 9253 E4 T250 D3 T254 E6 T258 I4 T262 E18
14 15 16 17 18
12.2V
BDW94CFP
7250 0V
12.2V
*
2266
2u2 100n
6272
BZX79-F10
3258
47K
3256 3257
2.3V
1K 1K
2.3V
21V
* *
0V
18.4V
17.8V 3284 2263
0V 2K2 47u
7251
BC847B
0.57V
BC847B 3260
0.57V
3259 7252 * *
220K
*
2264
330R
47u 0.58V
3262
0V 1K
3261
2262
0.58V
82K
1n
9.2V
(forseen only)
0.4V
3265
9.8V
MC20
1R
BC369
13V
7254 13.8V T262
9256 9254
+B
0.4V
3266 6273
12.3V
47K
15V 1N4003
13V
(forseen only)
8.5V
10.6V
3267 3268
9.1V
2K2 2K2
MC20
0.14V 0.14V
10.6V
0.14V
0.7V
15V
0.7V 0.14V
3269
STANDBY MC20
7255
22K
0V
BC847B
MC20
9.1V
10.6V 9.8V
3275
470R
BC327-25
13.8V 15V
12.9V
7256
MC20
12.9V
5.35V
9.1V
BC327-25
10.6V 9.8V 5.5V
13.8V 15V
7257
5.7V
MC20
12.9V
BC327-25
8.4V
13.8V 15V
10V 9.3V
7258
13.3V
9.1V 6275
3276
2K2
10.6V 14.5V
BZX79-F3V3
9.8V
12.3V
3278
MC10
2.85V 2.8V 47K
2.7V
7259
BC847B
2.35V 2.2V
2.1V
3274 3277
390R 2K2 BC847B
(230V MAINS SUPPLY ) DC VOLTAGES MEASURED IN :
V CD Mode 1KHz , 0dB track, DSC "OPTIMAL", DBB "OFF", INCR "OFF", VOLUME "20"
V
Tuner Mode 1KHz , df "22.5kHz", DSC "OPTIMAL", DBB "OFF", INCR "OFF", VOLUME "20"
V Standby Mode
14 15 16 17 18
19 20 21
A
T261
+12V BACKLIGHT
ETF_MOTOR (MC20)
*
9252
+AMP
B
*
4250
+12V_AF TUNER
*
7253
C
BC368
+12V_AF TUNER
ETF_AF
*
3264
(MC20)
1K
*
2265
100u
D
E
+CD_MTF_MOTOR CD SERVO
MTF_MOTOR (MC10)
F
G
H
T263
I
+5V6 uP
CD
BC807-25
5.35V
7260 5.5V T264
+5V6_S AF
0.5V RDS
MTF_AF (MC10)
J
4.8V
ETF_LOGIC (MC20)
5.67V
4.6V
3279
1K
0V
0V 5.67V
3280
7261
STANDBY K
22K
0.65V
0.65V
0V
L
19 20 21