repairing broken traces on a PCB

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tracks/distance.

Hmm, worth a try. I'll try fishing it out of the rubbish bin then, and see if there not too many vias and resolder them, perhaps. I didn't think about the vias this time.

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Thanks, Frank.
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I was frustrated when I had this problem with an smd prototype after changing a few components several times by hand, I too found flexing the board can make it not work as well, ive found that ceramic smd capacitors can go half open circuit, acting like a bend sensitive variable capacitance !

I only realy got to the botom of this when I found a capacitor that changed in value the tighter i held it in the probes of the capacitance meter. took me a while to work out the connection.

Colin =^.^=

Hi

Ceramic capacitors are notorious for cracking on a PCB subjected to warping or shock, particularly around the outer edges. You should try to place the footprint a little in from the edge as good design practice. You will not usually notice the issue electrically if it is a decoupling cap as the others on that supply are making up for it, also the cracks usually take place where the ceramic joins the end cap and are not visible under high magnification. Be sure the operators are not misshandling or using a rough tool to remove the PCB from the panel after assembly. A company call Syfer

manufacture a 'flexicap' which uses a flexible epoxy to join the ceramic to the end cap therefore making them more resiliant to flexing. I handled an issue with a cracked SMT cap on roughly 1000 PCB's by replacing the standard cap with a flexicap so the PCB's could be used in production, while the operators were doing that I moved the footprint in more from the edge and didn't have any problems from the next batch on.

Alan

I bought a signal generator that failed to power up. I checked the power supply and it was OK, but the circuit wasn't energized. I followed the power trace, and realized that the voltage stops on a fat trace near the edge of the board, right after the area with a mounting screw. I had to use a magnifying glass to see the crack---apparently the unit was dropped and PCB cracked. I soldered a piece of wire across the crack, and it all works now. I was lucky that it was a fat trace, and that it was the supply and not some internal circuit.

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capacitors

capacitance

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Thanks, its interesting there are components more resiliant to flexing, as I said its only a problem in initial prototyping where ive had to change/resolder a component several times, and its a hand soldered hand made pcb, I often find the end cap comes off, sometimes I just cant get the solder to melt at both ends of the component with one soldering iron, sometimes think I shld make a pair of tweezers out of two fine soldering irons, maybe these exist already ?

I hate to think how the 'through hole' decoupling capacitors ive used would cope with any stresses that they might endure, fortunatly mass production or even long term reliability isnt required.

I think I might look for an alternative to smd/ceramic caps for some instances as im trying to eliminate sensitivity to even small vibrations.

Colin =^.^=

Colin

You should only solder one side of a ceramic chip capacitor or resistor at a time. If you solder both sides simultaneously, upon cooling, the constriction of the component and joints can cause cracking. Solder one side, then after a few seconds solder the other. If you are changing a component, get rid of all the old solder from the pads first, and apply with new solder.

Alan