I finally figured out why my scope was showing double lines after 3 hours of frustration

Turns out it was a bad grounding clip on the probe, not the actual circuit like I thought. Spent way too long checking solder joints before I swapped the probe and it fixed everything. Anybody else ever get tricked by something that simple?

2 comments

2 Comments

vera_lewis12d ago

That grounding clip thing is a classic trap but here's something most folks don't realize. A bad ground on the probe actually makes your scope act as an antenna picking up noise from the room around you. That double line you saw was probably your fluorescent lights or computer monitor bleeding into the signal through the ungrounded probe. Next time try moving the probe around in the air near different electronics and watch how the noise pattern changes. Its wild how much interference is floating around in a normal room. Have you tried using the 10x setting on your probe to see if that changes things?

rileyl9812d ago

Wait did you try wrapping the ground lead around the probe tip instead of clipping it? That trick saved me when I was chasing a weird 60Hz hum on a power supply once. The clip was picking up everything from my phone charger to the LED strip under my desk, but wrapping it tight and short cleaned it right up. I even held it near my laptop fan just to see and yeah the waveform went totally crazy, like you said its wild how much junk is floating around. And yeah the 10x setting helped too, it lowered the capacitance and killed that ghosting on the edges I was getting.