baa9b099   
   From: ccon67@netscape.net   
      
   On Jan 30, 4:48 pm, Jon Elson  wrote:   
   > DaveC wrote:   
   > > 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?   
   >   
   > Put in ANY frequency, as long as it is known.  Fire the gear up, and   
   > observe the video output with a scope.  measure the horizontal sync   
   > frequency.  Now, you can easily figure the ratio (up or down) to   
   > get the desired H sweep freq, and most simple monitors should sync   
   > to it, even if the number of vertical lines is a bit off.   
   >   
   > Jon   
      
   or get some scope with video lines countable, to find out 525 or 625   
   system ...   
   the rest is in google, or folks in this group   
      
   :-)))   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)