Nothing electronically wrong with this one. Only 2 broken potmeter shafts.
I removed the potmeter and then the broken shaft. Measured it and made a new one from brass. Why brass ? Just because I had 4mm hex stock and brass is very easy to machine.
At first it did not work but reseating the IC’s fixed it. It goes from 0,3 Hz upto 3 MHz, 20Vpp open circuit and amplitude is flat over the whole range.