Pondering the effects of bad soldering

spi

Well-known member
In the last year, I built 2 pedals where a tone control didn't have any effect--I fixed both of them by identifying a bad solder joint on the tone capacitor.

Those were easy to identify because the non-functional knob was a dead giveaway. But it makes me wonder how many pedals I may have built that have a component not working, but because it's not breaking the signal path or a control, it's not easily detectable.

Like maybe some of my builds are not reaching their full potential because something is off in the circuit OR maybe some accidental mod has upped the pedals game.

Anyone have stories to share around these kinds of mistakes?
 
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mnemonic

Active member
I built a jfet copy of an orange graphic mk II preamp. It sounded great the day I made it, then dark and farty the next day. I found changing the j201’s used seemed to make it sound good for a minute or so then it went back to sounding farty.

Turns out changing the jfets didn’t make it sound better, slightly flexing the board did…

I pulled my hair out over that for a couple days until, when carefully looking over the pcb for the 10th time, I spotted a single strand of wire wedged under two box caps, joining two legs that shouldn’t be joined. Touching just softly enough that contact would break periodically and it would sound normal.

Pulled it out and now it sounds great, but what a headache it was to track it down.
 

bowanderror

Active member
I built a jfet copy of an orange graphic mk II preamp. It sounded great the day I made it, then dark and farty the next day. I found changing the j201’s used seemed to make it sound good for a minute or so then it went back to sounding farty.

Turns out changing the jfets didn’t make it sound better, slightly flexing the board did…

I pulled my hair out over that for a couple days until, when carefully looking over the pcb for the 10th time, I spotted a single strand of wire wedged under two box caps, joining two legs that shouldn’t be joined. Touching just softly enough that contact would break periodically and it would sound normal.

Pulled it out and now it sounds great, but what a headache it was to track it down.
Intermittent issues like this are the WORST to troubleshoot. I've run into this when trying to wedge a large vero build into a 1590BB. Between board flexing, invisible offboard shorting, & sockets, it's like playing Operation.
 

Harry Klippton

Well-known member
I built a jfet copy of an orange graphic mk II preamp. It sounded great the day I made it, then dark and farty the next day. I found changing the j201’s used seemed to make it sound good for a minute or so then it went back to sounding farty.

Turns out changing the jfets didn’t make it sound better, slightly flexing the board did…

I pulled my hair out over that for a couple days until, when carefully looking over the pcb for the 10th time, I spotted a single strand of wire wedged under two box caps, joining two legs that shouldn’t be joined. Touching just softly enough that contact would break periodically and it would sound normal.

Pulled it out and now it sounds great, but what a headache it was to track it down.
I love reading troubleshooting threads for stuff like this so I can learn from other's mistakes. I HATE asking for help so my usual method of troubleshooting is to imagine what I'd write and what the responses I'd get would be, check that shit, and then usually I can fix it
 

Big Monk

Well-known member
My MO for the last year or so has basically been to solder a component in place, clip leads and touch it again before moving on. I try very hard to maintain my soldering top as well. My current tip is almost a year old.
 

Feral Feline

Well-known member
That's similar to the method I adopted as well. Touch up all the joints after clipping the leads, but I still do several components in one batch instead of one-by-one.
 

andare

Active member
I built a Minnow that had a volume drop. Cleaning the PCB with isopropyl alcohol revealed several pads with no solder (or maybe removed solder?).
I took it out of the box, reflowed every bad joint and now the volume issue is still there and as a bonus it sounds worse than before haha.

I probably cooked an IC, who knows, I'll never find out. Too many components...

Now I'm also inclined to touch every solder joint but I'm afraid of cleaning PCBs lest I make another mess.

The only time I was able to clean a PCB nicely was right after finishing populating it. If I wait a few days the flux just spreads around in a sticky mess.
 
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