The oscillator part works fine. My intention is to scale the triangle wave at the output of U1 to +/-2.5 V by using U4. In the simulation this works correctly; the gain of U4 is of course -(68/100) = -0.68, or 0.68. In the simulation the triangle wave at the output of U4 is approx. +/- 2.5 V.
However, on the breadboard, Vtri at the output of U4 appears as a triangle wave equal in magnitude to its original wave. If I increase or decrease R9 it has no effect on the gain. I am not sure why. Perhaps the way I am trying to couple the output of U1 to U4 is not working the way I want? I also tried AC coupling the output of U1 to a noninverting amp, but this didn't work either.
I thought maybe somehow my 074 was damaged; I popped a 324 into its place and I got the same result. I am not sure why.
Can anyone suggest a way for me to amplify the output of U1 by 0.68, preferably with my 074 op amp?