T
Tim Williams
- Jan 1, 1970
- 0
Joerg said:Ouch! That doesn't exactly speak to the competence of the guys who
designed it. Or maybe they didn't do design reviews?
I have a Wavetek 193. Excellent generator, but then the output stage died.
Same damn thing, driving a load at high amplitude...then suddenly not
driving it.
The output stage is an AC coupled RF follower using 2N3866 and 2N5160, one
set to drive and two pair for output. (An op-amp controls bias, including
"DC" output signals.) They all have heatsinks, but TO-39 isn't renouned for
heat dissipation.
Here's a picture of the layout. Schematics are on BAMA, IIRC. This is
actually some guy's 191, which has the same main board as the 193, and looks
the same as mine used to. Now I have two ugly TO-126 transistors on small
heatsinks where the four outputs used to be. Risetime sunk to an appalling
50ns.
http://myweb.msoe.edu/williamstm/Images/Wavetek_191_Output.jpg
Tim