Sniffer XR-71 help

[Jafar]

The diodes are dead , remove them and check them, the voltage over there should be 0.6Vpp, increase R6 to 1k.

“I increased R6 to 1 kΩ, but the peak‑to‑peak voltage didn’t change and remained the same as before. I even reduced the resistor to 500 Ω, but still nothing changed. I lowered it further to 330 Ω, yet again no change occurred.”

[pito]

if diodes are ok ( not burned out ) then there is no needs to change resistors, your problem is in this area, add a capacitor as on the drawing, check DC voltage on both sides of the diodes ( betwin ground and diodes ), with coil and withouth coil.

[Jafar]

“Is the capacitor shown in the picture not sufficient?
Should I add the capacitor you mentioned?”

[pito]

Should be enough, DC voltages on diodes ?

[kt315]

green trace is the output of the LF365 at pin 6, and the yellow trace is the input of the LF357 at pin 2.
I still don’t understand what you mean by the ‘classical’ view.

Also, in my new board I’m using a 7812 to keep the voltage fixed at 12 V.”

MAIN RULE is - if you measure the analog signal ie opamp output, you have to set GND-GROUND probe of your o-scope on D6A pin 1 - Voltage Divider (your schematic).

Classic is TYPICAL FORM OF THE SIGNAL. your signal is ununderstanding for me.

[pito]

Take another photo of this area on both sides of the PCB

[Carl-NC]

Your oscope is set to use 10X probes; are your probes also set to 10X, or are they set to 1X?