CA3080 saturation/lock up?

[jh]

>I have a ckt which appears to lock up or something 
>(resets after 30 seconds or so) possibly when the
>input signal peaks...
>is the 3080 susceptible to this?
>the only other thing in there is a TL072, which i cant
>remember seeing do anything like this..

I don't know about the specific circuit, but here is one hint:

JFET input opamps can invert their output when the negative
common mode range is exceeded. So if you use  such an opamp 
to buffer a 3080 output, never use the opamp as non-inverting
unity gain buffer.
I have once built the VCO core of the Bode Frequency shifter,
which uses exactly this configuration, but with a bipolar opamp.
I put in a FET opamp (not sure if it was a 072, might as well
have been an LF353), and ... at first everything was fine, because
the oscillator was designed for a triangle wave of a few volts only.
But after switching the circuit off and on, sometimes it would
lock. If one opamp inverts its output state, negative feedback will
become positive feedback, so lock up is possible.

JH.