Hello,
I have built on a breadboard a curve tracer that uses the sine wave generated by a Wien oscillator. The breadboard version works fine. I have built a smd version for which I made a PCB. The smd version is not working despite being mostly identical to the breadboard version. The only difference is the switchable filter in the smd version. It is not my design, it is Mr. Carlson's, except the Sine wave generation part.
At pin 1 of the TL074 I am getting nothing, only random noise, not even a square wave. At this point I am scratching my head in despair as I do not know how to tackle this situation. I have to admit it is my first time working with smds and oscillators.
Here is what I have checked:
1. Placement of the components and solder joints. (No solder bridges on TL074, all pins are soldered fine, no shorts)
2. Split supply generated by LM358 (it is fine, the TL074 is receiving proper power)
3. Any mistakes made in the tht to smd transition. I only found an extra 100k resistor which i just removed.
What boggles me is that I used the same LM358 and TL074 for the breadboard version which works fine as I am writing this. I have not changed any component values. I am using the same 1N4148 diodes.
Thank you for taking your time to read this. I have attached the relevant info below.