Please explain bad traces to me

[brightlight]

On a few occasions I've come across people here saying a board had a bad trace and only once jumping that component to the next one did it work.

Is this a result of a faulty board from the factory or something the user caused? How do you find them? Only by audio/continuity probing? How exactly do you jumper the faulty trace? Is this common?

Thanks!

 

[JamieJ]

Sometimes if a component has received too much heat the trace can lift or become damaged. I wouldn’t say it’s hugely common but something to consider when you are trouble shooting. Good inspection, continuity testing and audio probing can help to work it out. There can be “bad traces” if a board isn’t designed correctly also. This is where the schematic either hasn’t been designed correctly or not transferred to the PCB correctly so that that trace doesn’t exist as it should.

This is an example of a pretty large lifted trace. They can be a lot smaller than this:

 

[brightlight]

Sometimes if a component has received too much heat the trace can lift or become damaged. I wouldn’t say it’s hugely common but something to consider when you are trouble shooting. Good inspection, continuity testing and audio probing can help to work it out. There can be “bad traces” if a board isn’t designed correctly also. This is where the schematic either hasn’t been designed correctly or not transferred to the PCB correctly so that that trace doesn’t exist as it should.

This is an example of a pretty large lifted trace. They can be a lot smaller than this:

View attachment 45324

Ok, thanks for the picture example! So a bad trace is the copper "path" from one pad to the next? Or a bad trace is the pad itself?

How does one correctly jumper these? And are these somewhat common?

 

[JamieJ]

A trace is the copper from one pad to another. It is normally within the PCB. They are “bad” when they are damaged or they lift up like in the picture because the PCB itself has been damaged.

Pads can also be damaged and lift or fall apart if they are repeatedly over heated.

You diagnose the trace that was damaged and use a jumper to effectively replace the damaged trace.

Inspect where the trace goes too and from (be aware that traces can split into multiples or go through a via. Check on the schematic that you know what that trace supplies. Then solder a wire between the components to “replace” the trace. I hope that helps.

 

[PunchySunshine]

And are these somewhat common?

They are when I'm desoldering!

 

[Brett]

They are when I'm desoldering!

Desoldering can be a pain!

 

[brightlight]

A trace is the copper from one pad to another. It is normally within the PCB. They are “bad” when they are damaged or they lift up like in the picture because the PCB itself has been damaged.

Pads can also be damaged and lift or fall apart if they are repeatedly over heated.

You diagnose the trace that was damaged and use a jumper to effectively replace the damaged trace.

Inspect where the trace goes too and from (be aware that traces can split into multiples or go through a via. Check on the schematic that you know what that trace supplies. Then solder a wire between the components to “replace” the trace. I hope that helps.

Thank you!

 

[KR Sound]

How does one correctly jumper these? And are these somewhat common?

Not very common unless the board’s been damaged.

I’m working on repairing some pulled traces from when someone tried to replace an IC. Here are some good videos explaining the process:

 

[DGWVI]

On a few occasions I've come across people here saying a board had a bad trace and only once jumping that component to the next one did it work.

Is this a result of a faulty board from the factory or something the user caused? How do you find them? Only by audio/continuity probing? How exactly do you jumper the faulty trace? Is this common?

Thanks!

I've gotten a few boards with factory defects- a couple boards have had pads linked to ground that shouldn't have been, and in other cases traces completely missing between pads that definitely should have linked.

This has only been about 4 boards out of at least 1000

 

[Chuck D. Bones]

I've gotten a few boards with factory defects- a couple boards have had pads linked to ground that shouldn't have been, and in other cases traces completely missing between pads that definitely should have linked.

This has only been about 4 boards out of at least 1000

Too many people are ready to blame the board or the components when the real cause of circuit failure is workmanship. If a pad or trace is bad, in all likelihood it's the guy with the soldering iron that made it that way.

 

[DGWVI]

Too many people are ready to blame the board or the components when the real cause of circuit failure is workmanship. If a pad or trace is bad, in all likelihood it's the guy with the soldering iron that made it that way.

My most recent was this Parasit Sidescroller. That's pin 11 of the 4069 with a clear trace to ground, where there shouldn't be one



I also have a Griffin FX Buzz King board that has traces completely missing, I'll try to dig it up and take photos

 

[Chuck D. Bones]

I believe you. It happens, I've seen it.

My point was out that a 0.4% failure rate for board manufacturing is very good. Our workmanship should be so good.

 

[DGWVI]

I believe you. It happens, I've seen it.

My point was out that a 0.4% failure rate for board manufacturing is very good. Our workmanship should be so good.

I've built a few things in my time, and my most common failures are still upside down or missing chips

 

[brightlight]

Too many people are ready to blame the board or the components when the real cause of circuit failure is workmanship. If a pad or trace is bad, in all likelihood it's the guy with the soldering iron that made it that way.

This is kinda what I was wondering in terms of how common this is. It seems factory flaw is the exception and user error is the rule.

Visually would it always be fairly obvious that something isn't right? Or can the (rare) flaw be under the board unseen? The examples in the videos shared above are obviously very visible

 

[Laundryroom David]

This is kinda what I was wondering in terms of how common this is. It seems factory flaw is the exception and user error is the rule.

This is why troubleshooting begins with cleaning the board and making a close visual inspection.

As a side note, It’s AMAZING how I have had zero dead builds since I started testing components before building.

Edit to clarify: testing components has not yielded any great surprises for the most part, but it does force one to slow down and make sure that 10k or .22 uF actually is.