17 Sep
2008
17 Sep
'08
7 a.m.
From: derschjo at msu.edu
---snip---
Now check for the 5V reference voltage from pin 14 of U4 (the TL494).
Hmm, I get 6.75V (measuring from Pin 7 (gnd) to 14.)
Now, I think that TL494 should be oscillating, at
least at startup. See if
you get anything on pin 8. A TL494 datasheet would be a useful thing to have!
7.91V on pin 8. (I have a datasheet at
http://yahozna.dyndns.org/scratch/tl494.pdf). I scoped it out, and pin
5 is oscillating, a nice sawtooth.