The outputs that feed the Zeners are AC coupled with a zener and a 100K to
ground. My guess is that the zeners just clamp the voltage to a safe level
for the 6739 inputs. Look at the 6739 data sheet and find out if there are
any input voltage constraints for starters.

A bit suprising that Zeners would be used to clamp video lines...since they
typically have a high capacitance. This leads me to think that they may be
some other type of clamp diode.
Oppie


"Jerry Lynds" wrote in message
news:2l6Vh.7705$VF5.3567@edtnps82...
Hello,


I need some help determining what value of zener diode is in the path
between the LMH1251 RGBout and the input of the LMH6739.

D1, D2, D3 in schematic below...

http://img333.imageshack.us/img333/6...scoder29mx.gif

or

http://www.national.com/ds/LM/LMH1251.pdf page 9 figure 2



Thanks!

Jerry