[sdiy] Help trouble shooting noisy circuit

Joe Frey frey at radioles.com
Mon Jan 13 00:03:55 CET 2025


Hello, more than a decade ago I built with Harry Bissell's help a pitch 
to voltage circuit and an envelope follower and then built some 
supporting boards: power supply and two invert-offset circuits. One of 
the invert-offset boards is not functioning properly. It is a photo 
etched circuit board unlike it's brother that was made on strip-board. 
The invert and offset functions work properly but the output has a high 
frequency wave in it whether there is an input voltage or not. The 
brother circuit on strip-board works fine. Same power source for both. I 
have checked the component values(there are only resistors), checked all 
the traces with the circuit on paper, re-flowed all the solder joints 
and replaced the TL072  with others. I still have the issue. What should 
I look at next?

Is it possible that a faulty IC socket could produce this effect? I 
didn't change the socket because this basement darkroom circuit board I 
made then seems pretty fragile.

Thanks for any help. JoeF.




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