General questions about damaged PCBs and repair solutions

[jinx_defusing]

Hey everyone,

I'm a bit rough with my pcbs. And this roughness is totally unwarranted. Every step of the way should be done with light touch, so I'm trying to pull back the reins. Go slow. Be gentle. Use only as much solder and heat as is needed. So on and so forth.

Anyways, I have some questions about damaged PCBS:

What do you all do when you have damaged or completely destroyed a contact point (not sure if this is proper terminology. I mean the little metal circles that you solder the leads to)?​

1. What if the contact point is only damaged on one side?
2. both sides?
3. I use a copper wick to de-solder, but using this is what most often leads to damaged contact points. Are solder suckers safer to use? I can't seem to make them work well for me.

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When you scratch the surface of the PCB and reveal the copper that was beneath the surface, how concerning is this?​

1. I'm concerned that the scratch can act sort of like a jumper between any conncections that come into contact with the exposed copper. However, copper is an insulator, right? So is it right to assume that the current will not travel across the scratch/exposed copper?
2. If this is a problem, what can be done about it? Is there a way to cover the exposed copper?

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Sometimes, my iron will come into contact with components that are already soldered on to the PCB. Capacitors, usually. This happens mostly with polypropylene film box caps. It's easy to melt off a small bit of the capacitor's outer layer.​

1. If I just barely nicked the edge/ coroner, can I still use this component? Or is it fried at that point? Can I determine that by using a multi-meter?

 

[temol]

Stop worrying about melted plastic on caps.
Copper is excellent conductor. It's all about copper in pcb's You can use nail lacquer to cover the scratch.. or do nothing if it's small and wont' get in contact in potentiometer cans, enclosure, etc..

There's no single method of repairing damaged pads. It the pads lifted off the board - try to bridge the connection. If there's some pad left - handle with care, use as usual..or bridge it also.

 

[jinx_defusing]

Excellent! Thank you for the replies.

So when I bridge a connection, I can just refer to the schematic to figure out which solder joint I need to connect to. That should be no problem.

As far as how to bridge the connection, I am guessing the way to do this may depend on the the situation that I'm dealing with.

Since copper will act as a conductor, then I could make some scratches and use that to help me bridge the connection. Right?

For example, could I jsut find the little path where the current needs to run along, make a little scratch on it, then bend the lead on top of the scratch, and add a bit solder?

Alternatively, could I add a wire to the circuit? With one end soldered to the component and the other end soldered onto the next joint on the currents path?

 

[temol]

You can run a wire to the closest pad from the same circuit node or you can scrape off some soldermask from the track (the one with a lifted pad) and just bend a capacitor or resistor leg and solder leg directly to the exposed track. Improvise

 

[jinx_defusing]

haha ok great. I might as well experiment a bit. Best case scenario, I get a few new working pedals from this pile of wrecked PCBs that I have laying around. Worst case scenario.... I still have a pile of wrecked PCBs. Nothing to lose at this point!

 

[Mcknib]

1. If I just barely nicked the edge/ coroner, can I still use this component? Or is it fried at that point? Can I determine that by using a multi-meter?

I think if the coroners looking at it, it's definitely dead!

 

[jinx_defusing]

I think if the coroners looking at it, it's definitely dead!

omg... this took me a minute. No, it took me like two days. wow. hahah

 

[zgrav]

you cannot really fix a broken connection on a PCB by trying to scratch the board to expose more copper. the fix is all about connecting something else conductive on each side of the broken trace or broken connection.

 

[jinx_defusing]

you cannot really fix a broken connection on a PCB by trying to scratch the board to expose more copper. the fix is all about connecting something else conductive on each side of the broken trace or broken connection.

Ok, let me know if I understand correctly:

If I need something conductive on each side of the broken trace, then I could use a wire?

I would solder one end to the leg of the component that would normally be soldered to the pad that was lifted. I could add a good amount of solder so that it will fit snug in the through hole, and it won't move around.

And then I would solder the other end of the wire to the next pad in the circuit. I think this is basically like jumping, right? Except I'm not trying to bypass any of components, I'm jsut bypassing the part of the PCB that is damaged.

 

[zgrav]

You got it. Use a wire to jump the break. You can use the leads clipped off of your resistors and capacitors if you can connect to each side of the break, or use an insulated wire to make the connection between two component leads that are supposed to be connected based on the schematic.

 

[Mcknib]

You're correct that's exactly what you do

The best way to look at board traces is as wires thats basically what they are connecting components in the correct order so if you damage a pad or trace you simply hardwire or bypass it with a wire jumper

I do it on the underside of the pcb stick your component leg or pin through the pad hole attach your jumper and solder to the next component like this because these required short jumpers I just bent the component leg over and used that

 

[jinx_defusing]

You're correct that's exactly what you do

The best way to look at board traces is as wires thats basically what they are connecting components in the correct order so if you damage a pad or trace you simply hardwire or bypass it with a wire jumper

I do it on the underside of the pcb stick your component leg or pin through the pad hole attach your jumper and solder to the next component like this because these required short jumpers I just bent the component leg over and used that

View attachment 11447

Seems simple enough!

Almost done with the stockade (eqd palisades clone/ several TS clones in one). I just need to jump one connection, drill my enclosure, solder the pots, and solder my wires.

I was so damn careful with this build. I used to pray to the PCB gods, but they never answered. This time, I checked every damn component several times to make sure they were placed correctly. And I used a magnified lens to look over all of my joints.

If this works, then I will also try to fix 4 other PCBs that are 98% done but just need 1 or 2 jumpers.

Ok, this might take a while. Hopefully, I will have 5 new pedals and some very annoyed neighbors before the end of the night.

 

[jinx_defusing]

so the stockade is on hold. I could have sworn I had at least 3 stomp switches to use for this, but I can only find 2. Which brings me to another set of questions (unrelated to the topic, but don't think it needs it's own thread).

There seems to be 6 places on the board where one can place LEDs. The build calls for 3 LEDs (I assume there's one that corresponds to each of the stomp switches). So what's with the 3 extra spots for LEDs? Is this just to give me options about where I would like the indicators to be? If so, then do I just leave the unsused spots alone? Or will those need to be jumpered to themselves to close off the circuit?



One last question... I just noticed the through holes for wiring up the stomp switches are not labeled. I know that technically, they don't need to be. I just have to copy the diagram. But I was planning on using breakout boards on my stomp switches. And so... yeah. I will probably screw that up. please help lol.

 

[mitch]

Re: LEDs - the build doc actually calls for 6 LEDs.

The "DIODES" section has 3x 3mm Red LEDs, which are used as clipping diodes. These are the three you circled in the upper right area of your pic. The LEDs listed in the "LEDS" section of the build doc are the indicator LEDs - and they show if Bypass/Boost/Gain are engaged. There is an indicator LED located above each stomp switch in the diagram.

You can use any color LED for the indicators, but stick with Red LEDs in the clipping section if you want the stock sound. Different color LEDs have different forward voltages, which will alter the sound. You could also try socketing the clipping LEDs and experiment with different colors.

 

[jinx_defusing]

Re: LEDs - the build doc actually calls for 6 LEDs.

The "DIODES" section has 3x 3mm Red LEDs, which are used as clipping diodes. These are the three you circled in the upper right area of your pic. The LEDs listed in the "LEDS" section of the build doc are the indicator LEDs - and they show if Bypass/Boost/Gain are engaged. There is an indicator LED located above each stomp switch in the diagram.

You can use any color LED for the indicators, but stick with Red LEDs in the clipping section if you want the stock sound. Different color LEDs have different forward voltages, which will alter the sound. You could also try socketing the clipping LEDs and experiment with different colors.
View attachment 11512

Holy crap thank you so much. I can't beleive I overlooked that. Ok, well, not a problem. I have a bag of 50 3mm red LEDs.

 

[EGRENIER]

Just jumping in, about your challenges of using wick... I use it all the time and never burnt off a pad. Which makes me wonder if you iron may be to hot ? I keep min at about 730F or 390C, what's yours at ?

 

[jinx_defusing]

Just jumping in, about your challenges of using wick... I use it all the time and never burnt off a pad. Which makes me wonder if you iron may be to hot ? I keep min at about 730F or 390C, what's yours at ?

D'oh

Its probably between 800F and 900F. Hard to say since there is no digital display. But I crank the temp control close to it's limit.

 

[EGRENIER]

D'oh

Its probably between 800F and 900F. Hard to say since there is no digital display. But I crank the temp control close to it's limit.

This may be the source of your problems and why you are pulling so many pad off, at that temperature, you margin of error are slim. I would try to dial it back a bit and see if this help...