I have a gyroscope (MPU-650 on GY-521) connected with an Arduino Uno. The sensors works fine and I wanted to "sniff" the I2C data using a logic analyzer (ScanaQuad 100). This works if I only attach a probe on the SDA line and connect to GND. When I try to connect the SCL probe the sensor stops working.
For error searching I used an oscilloscope. Connecting to GND and SDA line works perfectly and I can see digital signals and measure 3.3V. Also there I have same problem that when I connect a probe on SCL line, the voltage drops to mVolts and stops working.
As an electronics newbie I would appriciate some advice on how to deal with this and possible explanations. I bought the logic analyzer and oscilloscope to learn more about electronics and to aid in error searching. Now these tools are part of my "challenge" and learning curve.