What was your most annoying circuit last year

[Shortwhile]

Last year, I was haunted by a control board that only decided to act up at the most inconvenient times. I'm curious about what everyone else struggled with. What was the most frustrating circuit you had to tackle?

 

[capacitorkid]

Built a sensor circuit that worked perfectly… until humidity showed up. Took forever to trace it to leakage across flux residue. Now I clean boards like a ritual.

 

[Tovaren]

Once chased a ghost bug in a compact audio board that vanished whenever probes touched it.
Weeks later, found a cracked ground via. That board aged me.

 

[OhmMy]

Had a motor controller that only failed after lunch, never on the bench. Turned out to be a drifting regulator. Spent more time side-eyeing it than fixing it.

 

[barfle]

I have a groovy lamp that senses sound in the room, and changes color when there are sound peaks. The circuit is dead simple - an opamp with hysteresis and a couple of triacs. It works perfect on the bench, and just acts like a flashing light when it’s packaged up.

Still on the “someday, hopefully soon” pile.

 

[OhmMy]

I have a groovy lamp that senses sound in the room, and changes color when there are sound peaks. The circuit is dead simple - an opamp with hysteresis and a couple of triacs. It works perfect on the bench, and just acts like a flashing light when it’s packaged up.

Still on the “someday, hopefully soon” pile.

I know the feeling. Everything runs perfectly in theory, but once you put it all together in real life, it becomes a puzzle. Here’s hoping it gets sorted out soon