"DaveC" wrote in message
...
80's vintage German printing equipment (offset press industry) uses a
video
plug-in card (made by the manufacturer of this equipment) to generate
parameter display for the operator. The display is a standard baseband
video
tube monitor. (It is possible, being German and sold in the USA market,
that
the video may be NTSC or PAL.)

There is no video signal on the BNC output connector.

This is used equipment being resurrected, so operational history is
unknown.

There is a place on the video card labeled "Q2" that is the right shape &
size for a crystal can. The pads look like it was ripped off the board: a
short lead soldered in one pad; a hole in the other pad where a lead was
soldered (poorly, apparently!). (Rough handling is a distinct possibility:
the client is a used-equipment dealer and the fork lift is their main
tool...).

The board is populated with 80's technology, mainly 74LS' :: the crystal
pads
connect to an 'LS04 inverter/driver and then to an 'LS96
parallel-to-serial
converter. The 'LS96 spec sheet says that it can be driver up to 25 MHz.

The board uses a 8275 CRT controller, and in the datasheet it says: "CCLK
is
a multiple of the dot clock and an input to the 8275."

Maybe these clues will tell someone what frequency this crystal needs to
be...?

What frequency crystal should I be looking for?

Thanks.

Can you feed in a test signal from a signal generator and see what you get
on the display? A line in NTSC is about 64 us. If you have 80 characters x 7
dots, that's 560 dots per line or about 0.114 us per dot. That gives about a
9 MHz clock frequency. Maybe you can find a good signal generator and start
out in that range. At least it would give you a clue as to what the video
format should be.