Schematic for VA48 Sencore

[JohnCT]

I have the quick setup guide and full operator's /maintenance manual, but I don't have a full schematic (I have a partial someone sent me a while ago).

Mine has no bar sweep and intermittent color bars, so I'd like to start at the 500 board. It does generate a cross hatch and dots though.

If anyone has the schematic for the 500 board, PLUS, the parts location grid for the 500 board (lots of chips, none with silk screened legends) on a .pdf, I'd appreciate it.

Thanks.

John

[JohnCT]

Guys, two friends scanned and emailed me sections of the original schematic.

If anyone wants a copy, email me and I'll forward what I have. Between the two, it's a mostly if not complete schematic.
delstv/at/aol/dot/com

BTW, looking over my 500 video generator board, there are a lot of factory revisions not shown on the schematic. Most seem to be with dropping the Vcc to the chips.

Instead of 15V, I was getting about 14.4 from the power supply. There was no continuity between the boards but I do read a diode in the line front to back, so they dropped the 15V source to the 500 generator board. They also opened up the Vcc line to the crosshatch generator IC and put in a 2.2V zener, so the generator chip now runs closer to 12V than the original 15v.

There are also transistors and resistors added to the top of the board and tacked onto ICs, so I'll have to deal with those.


John