I had my plumber change the PCB of my boiler last year. Last week it stopped working and I tried to troubleshoot the problem. The circuit board just doesn't show any sign of life, the ON LED doesn't turn on at all.
On the board I see a brown area. I suspect it has burnt but the damage doesn't look really important, so I would like to check with you if this indeed looks like burnt damage and if that could make the whole PCB dead:
Thanks in advance
Best Answer
You've got three 33 ohm resistors in series there, (R1,R2,R64) someone did that on purpose, probably because they needed a higher wattage than a single resistor could handle.
That sort of discolouration is fairly common where boards get hot. it does not necessarily indicate a fault.
If the board gets too burnt it can become conductive, your board is part-way there. but I don't think all the way there.
Remove the resistors (R1 R2 R64) and measure the resistance on between the pads where R2 connected, if it shows less than 1 Mega ohm the board is damaged, if not the fault lies elsewhere. .