How to reset a relaxation oscillator

[Ilya]

I'm trying to modify the following LFO circuit of a synth so it can be synchronized from external pulses. The goal is to get the oscillator to restart each time the pulse arrives.

I was able to force the restart by shorting C1, but each such restart begins with a huge spike. This is especially prominent on the triangle wave output.

Is there any way to gracefully restart this circuit? Any ideas?

 

[zamproject]

Hello

What about the top of C1 (TP1) at 0V ?
By shorting C1 you force everything at -12V

Or one low R in serie with C1 + one high R in parallele (in serie with the short) to ramp a little ?

 

[Ilya]

Here’s what worked for me. I limited the pulse to 5V and managed to get a relatively clean restart.
Thanks for suggestions. This is an existing circuit, so modding it as little as possible is a benefit.