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vampyretim · 25th Nov 2020, 4:01 pm

Hi,

I've just recapped this old sig gen but am getting (and was prior to recapping) an out of phase second oscillation on my scope which is fainter than the main one. The oscillator seems to be a bit unstable on lower frequencies and on the lower p to p settings, ie; I get distorted waves that bounce about a bit on the x1mv and x10mv (x10 and x100).

I've been reading up on the wien bridge circuit and was wondering if there might be a problem in the feedback loop hence why I have an out of phase trace. I've never attempted to repair a sig gen before and was looking for some guidance, I have the service manual for it but don't know how to properly shield the oscillator circuit whilst also being able to tweak it.

Any help greatly appreciated.

25th Nov 2020, 4:01 pm	#1
vampyretim Heptode Join Date: Aug 2011 Location: Bristol, UK. Posts: 538	Farnell LF1 oscillator Hi, I've just recapped this old sig gen but am getting (and was prior to recapping) an out of phase second oscillation on my scope which is fainter than the main one. The oscillator seems to be a bit unstable on lower frequencies and on the lower p to p settings, ie; I get distorted waves that bounce about a bit on the x1mv and x10mv (x10 and x100). I've been reading up on the wien bridge circuit and was wondering if there might be a problem in the feedback loop hence why I have an out of phase trace. I've never attempted to repair a sig gen before and was looking for some guidance, I have the service manual for it but don't know how to properly shield the oscillator circuit whilst also being able to tweak it. Any help greatly appreciated.