Real world tips for testing printed circuit boards for hidden faults

[Voltgnome]

I’ve got a board that works... well, sometimes. There are no obvious burns, and the capacitors look fine, but something’s definitely off.
Intermittent faults are the absolute worst to track down! What’s your go-to process for spotting hidden shorts, cold solder joints,
or those pesky hairline cracks before you decide to toss it in the bin?

 

[soldersoldier]

I use compressed air to freeze it. If it misbehaves in the cold, it’s usually due to a cracked joint since the cold causes the metal to shrink.

 

[bit&board]

Then there's the tap test. You just lightly tap the board with the plastic handle of a screwdriver.
If it glitches, you’ve likely found a bad joint or a cracked trace.

 

[Circuitsmith]

I’ll reflow the entire board, focusing on the connector pins.

A cold joint might look fine, but sometimes just reheating can sort it out.

 

[Alan]

These tips are spot on. Using cold spray, trying the tap test, and doing a full reflow, especially on connectors, pretty much tackle the whole issue of intermittent problems. That mix has rescued more 'dead' boards than I can count.