PCB beeps only when power disconnected

Thread Starter


Joined Aug 1, 2014
Hi, I just bought a Philips air purifier (Series 1000) at a garage sale, for very cheap because it wouldn't turn on. I thought it would be an easy fix, but it wasn't. I determined that power reaches the main PCB. I'm not discounting that the problem could still be in the main PCB, but there is another PCB connected to the main PCB (I'll call the other PCB "pcb2") that controls the inputs (power on, fan speed, etc.). I found that pcb2 beeps and flashes lights now and then if I move it slightly, but only after I've unplugged the purifier (so that I can somewhat safely move pcb2 around) and only for a limited amount of movement. So I assume caps are making the beeps/flashes. I'm guessing I should resolder as many connections as I can on pcb2, but would appreciate any input....?
I could upload photos & all that but was just hoping for some quick ideas.