Here's the current schematic: http://marcansoft.com/uploads/images/transcoder.png I've fixed the problems and added power supply and sync processing. SYNC IN 1,3 are for the RGB inputs (1 and 3), and SYNC IN AUX is for expansion purposes (such as the addition of an LM1881 sometime, to provide sync separation for the RGB inputs, if needed). Sync for the YPbPr input (2) is of course always on-Y and separated by the LMH1251. The sync polarity is selectable through a pair of XOR gates. All the control signals will be supplied by a separate board (probably a PIC, once I get this board working). There's one little thing I'm left wondering about - should I put the 33ohm damping resistors (the ones that I added between both chips) before the capacitor and dc-biasing or after it? The LM1251 datasheet does it both ways in Figure 1 and Figure 2. I'll be off to buy the parts in a few days :) -- Hector Martin (hector@marcansoft.com) Public Key: http://www.marcansoft.com/marcan.asc -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist