Service manual

In order to display the external AV sources by the PIP panel, source selection circuit is
incorporated on the panel. In A10 PIP execution, 3 external AV sources are possible
(AV1, AV2/S-VHS1, AV3/S-VHS2). The selection between these sources is done by
IC7801 HEF4053.
Note: When S-VHS is inserted from the rear, AV2 source will be disabled. Likewise
when S-VHS is inserted from the side-AV.
The switching logic of AV sources is shown in Table-2.
Table: AV switching logic for PIP picture
Device
IC7403
pin Function
RF
(CVBS)
AV1 AV2 AV2SVHS AV3 AV3SVHS
4 S1 1 0 X X X X
5 S2 0 0 1 1 1 1
IO
Expander
9 S3 X X 1 1 0 0
Since the PIP processor input needs CVBS signal, the YC from the SVHS inputs (rear &
side AV) are being 'added' by TS7817 or TS7816.
PIP Processing
IC7803 M65669 is a PIP signal processor whose sub-picture is composite signal for
NTSC, PAL M/N. It also has a built-in V-Chip data slicer and built-in field memory (144k-
bit RAM). The PIP picture size can be 1/9 or 1/16, with picture freeze capability. The
composite video signal from the PIP tuner or AV source is fed to IC7803 pin-22. Since
the PIP is only NAFTA execution only one x'tal 1802 (14.3181MHz) is connected to pin-
28, for decoding the CVBS into NTSC YUV signals, in the digital domain for PIP
memory & output control. The compressed YUV then reconvert back to analogue by the