Service manual

CB-15
A/V Switching
On sets using the digital comb filter, CV is fed into an A/D converter at pin 5 of IC2400. This IC is pow-
ered by the +5VTune at pins 3, 12, 20, and 27. Output for chroma is at pin 23 and for luma is at pin 25.
Both are further cleaned by transistor circuitry that is powered by the +12VSW. Finally, combed luma
and chroma are returned to the A/V switch.
<<Figure CB-13>>
1
2
3
4
5
6
7
9
8
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
KILLER
VSS2
VDD2
CKIN
FILT
CBPF
VENH0
VENH1
1LINE
CORING
1/2VDD VDD3
VSS3TEST1
CLAMPC BIAS3
COUTBIAS1
A/DIN BIAS2
YOUTVREFH
VDD1 VREF1
VDD4VSS1
VREFL VSS4
IC2400
C2409M
C2412M
C2414M
C2415M
R2405M
C2417M
C2418M
R2408M
C2413
R2409M
C2419M
R2407M
C2446M
R2406M
+5VTune
L2413
C2445
C2444M
C2443
L2412
+5VTune
L2415
R2448M R2449M
C2449M
C2448
R2404M
Q2401
+12VSW
R2403M
R2402M
C2407M
L2402
C2405M
R2401M
C2406M
R2400M
C2451M
PROV
FSC
CV-Comb
C2423M
C2424M
R2446M
C2447M C2455
+5VTune
R2454M
C2459
R2461M
R2460M
+12VSW
1
2
3
4
5
DL2400
C2461M
C2450
R2471M
R2470M
L2411
C2471M
Q2413
Q2414
Q2411
+12VSW
23
46
L2409
23
46
L2408
Q2404
R2447M
R2436M
R2445M
R2444M
R2457M
R2439M
R2440M
C2439M
R2441M
R2463
C2442M
L2410
C-Comb
Y-Comb
+12VSW
R2455M
R2426M
R2427M
Q2405
R2416M
R2417M
R2458M
C2452
R2472M
Q2406
+12VSW
R2473M
R2474M
R2430M
C2453
**See Note!
IQB27B42W
IQB32B42W
IQB32B84R
IQB32B86R
IQB36B42W
IQB36B86R
**Note!
Boxed Areas
ONLY for these: