KV-1352 Video Input Hacking

The Sony KV-1352 CRT Color TV has no Component or CVBS video input.

However, there is an option enhancement "OPK-103" to add a "V-Board" into the KV-1352 which seems to provide Teletext-functionality. Additionally, the already present cut-out in the KV-1352s back case suggests potentially a SCART connector.

Nevertheless, I could not find hide nor hair about this miraculous "V-Board": there is no place to buy this board, not even hints to its part number, but also no documentation like functional description or schematic.

Therefore, let's try some reverse engineering in absence of the subject ...

= Extracting hints from the KV-1352 service manual

OPK-103 Teletext add-on mod

The KV-1352 Service Manual describes in chapter 2.6 adding the option "OPK-103" in the following (functional) steps (I added my interpretation of the effect these changes take on the TV):

1. cut JW2 (wire link) on the M-board
   • this leads to change input level on IC2 (M50120P) / Pin 24 (Mode2) from pulled down to ground to being pulled up, thus changing the remote control receiver from TV-mode to Text-mode
2. new connections:
   1. V1 - M12
      • M12-Signals:
        • n/c
        • GND
        • nDATA from/to remote control receiver controller IC2 (M50120P)
        • nDLIM from/to remote control receiver controller IC2 (M50120P)
   2. V2 - A14
      • A14-Signals:
        • 7 - KILLER
        • 6 - BLK - blanking
        • 5 - HP
        • 4 - SYNC
        • 3 - VIDEO
        • 2 - GND
        • 1 - +12V
   3. V4 - A16
      • A16-Signals
        • 1 - IH-Delay out
        • 2 - GND
        • 3 - GND
        • 4 - IH Delay in
   4. V5 - A11
      • A11-Signals
        • 1 - GND
        • 2 - R
        • 3 - G
        • 4 - B
   5. V9 - F7
      • a closer inspection of my KV-1352 showed that the same connector labeled with "F-7" on the top/component side of the PCB is labeled with "A-6" on the bottom/solder side ??? ...
      • (BTW: same seems to have happened with A15 (solder side) vs A-17 (component side), as well as A-16 (component side) vs. A-18 (solder side)
      • F7(A-6)-Signals (A-6 reference in the schematic)
        • 1 - GND
        • 2 - GND
        • 3 - n/c
        • 4 - +6V
        • 5 - +14V
        • 6 - n/c

What a possible Teletext decoder might do with these connections can be inferred from the Philips SAA5281ZP teletext Decoder Datasheet:

• gets CVBS input from the TV
• decode Teletext from the CVBS signal
• be controlled by an I2C or similar interface from the TV's remote control
• generate RGB text video rendering

The downside of this integration is that the RGB data from the text decoder cannot transport an sync information as the Teletext is displayed in sync with the video programme it is extracted from.

Soo, this seems to have been a dead end for now ...

OPK-102 "SCM Board mod

There seems to be another modification, adding a mysterious "SCM board" to the KV-1352.

Not knowing what a "SCM board" is meant to be, I again resorted to the involved connections and other modifications when applying this mod:

• "SCM" may be "SECAM" or "SCART" (something has to use this SCART cutout in the back cover, please!)

1. Disconnect A7 (normally connected to C-4)
2. Remove R344/R345/R346 (33k) on A-board
3. Remove R350 (100R)
4. Remove JW-35 (next to R337, labeled "SECAM CUT") on A board
5. Connect SCM Board
   1. SCM-4 - C-4
   2. SCM-5 - A-17
      • A-17(==A-15) signals
   3. SCM-1 - A-18
      • A-18(==A-16) signals
        • 1 - IH-Delay out
        • 2 - GND
        • 3 - GND
        • 4 - IH Delay in
   4. SCM-3 - A-7
      • A-7 signals
        • 1 - n/c
        • 2 - Blue channel
        • 3 - Green channel
        • 4 - Red channel
        • 5 - +12V
        • 6 - n/c
   5. SCM-2 - A-15
      • A-15 signals
        • 1 - GND
        • 2 - PIC - picture control voltage from remote control receiver
        • 3 - COL - color control voltage from remote control receiver