trouble with (multiple) Civil War muff builds

analog_bham

analog_bham

Active member
i have now tried two separate PCB builds with the Civil War muff specs from the Muffin Fuzz pcb and neither has been functional. i'm not sure what is going on. I've built them the same way as the multiple Triangles and the Dope Priest that have worked fine. I am using the KT3102EM transistors and verifying EBC (has a reverse pinout from 5088) with the DCA75. Just wondering if anything jumps out at anyone as an obvious problem. Wondering if i'm making a component error or something since it's happened on two distinct builds and all my others have been fine.

thanks!
John
 

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swelchy said:
some of the issue is soldering..... What exactly is it doing? Do you have bypass signal.. led light working etc etc
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I’m plugging it into a PPCB auditorium. There isn’t an LED (I used the 3pdt board with LED). Bypass is fine but no signal when turned on.

I’m not defensive about the soldering but if you can explain what’s wrong with it I’d appreciate it. They’re soldered from the bottom, small teardrops and shiny and kind of exactly what I was trying to do. The rest is flux that I haven’t cleaned off yet. But I’m learning from the internet so if it’s wrong, some guidance would be great!

Thanks!
 
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Erik S said:
Is it just reverse? Or would you also need to cross the legs?

Take the Google AI overview for what it's worth, but might be worth double checking.

View attachment 116838
Click to expand...
Diagram I found was reversed. And I used them in my Dope Priest reversed and that pedal sounds great! I’m completely at a loss. I need to go through it with the audio probe but wondered if just looking at it, someone might see something obvious since it’s two separate builds with the same issue.
 
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The areas circled in red are not quite soldered all the way... you didnt get full solder wicked to both sides of board and these could be cold joints.... Just trying to help but you need to give it another second longer to wick through.

IMG_1462.jpeg
 
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The cold joint issue swelchy flagged is definitely worth addressing first since a few of those circled joints look like they didn't flow through. On the KT3102EM pinout — just to confirm: you're installing them EBC left-to-right (as labeled on the PCB) and physically rotating/bending the legs to match the CBE order printed on the board? If the Muffin Fuzz layout was designed for 2N5088 pinout (EBC), then the KT3102EM (also EBC) should drop in without crossing. If it's still silent after fixing the cold joints, checking the voltages at each transistor base/collector would help narrow it down.
 
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You can chopstick the suspect joints and see if it shows any signs of life.

You can also use your multimeter to check continuity between those components and schematically connected ones. Make sure your probes are on the leads of the components and not the board's pads. If you can manage it, try to wiggle the components while you check.

Regarding soldering, I solder everything other than semiconductors and wire with melty insulation way hotter than any tutorial recommends. If you like your current pace, you might up the heat a bit to improve solder flow.
 
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Back from work and staring at the board again. 4.3v at q1-3 and almost 5 on q4.

Tracing back from output with audio probe shows a pretty significant volume drop at the tone bypass switch.

I did crank the amp and there is output from the pedal, just much lower volume than unity.

Edit:
Removed the tone switch and permanently bypassed. Still not working.
 
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Feral Feline said:
Have you reflowed the pads Swelchy indicated?

Maybe once you do that, it all works — then no need to proceed further with other trouble-shooting methods.
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Reflowed everything.

Using the audio probe with a tone generator, I have tone throughout, some louder than others, but always tone. I imagine I’m crossed somewhere but I can’t seem to find it.
 
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AAUGH!​

ac82d27d86b94211d48d004eacaa4cb0.jpg



Uhm ok.

Back to the ol' drawing board...

Triple-check all component values...

Maybe ... compare where the signal is "louder than others", maybe there's a pattern there?

Maybe it's a bad pot, or one (all?) of the transistors... I'm just spitballing here...

BILL THE CAT THPPPPT.jpeg
 
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Feral Feline said:
AAUGH!​

ac82d27d86b94211d48d004eacaa4cb0.jpg



Uhm ok.

Back to the ol' drawing board...

Triple-check all component values...

Maybe ... compare where the signal is "louder than others", maybe there's a pattern there?

Maybe it's a bad pot, or one (all?) of the transistors... I'm just spitballing here...

View attachment 116882
Click to expand...
My response has been very similar to Charlie Brown…

I wondered if it was a bad pot. After this weekend, I’m off all next week so I’m going to try to dig into it then.
 
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analog_bham said:
Back from work and staring at the board again. 4.3v at q1-3 and almost 5 on q4.

Tracing back from output with audio probe shows a pretty significant volume drop at the tone bypass switch.

I did crank the amp and there is output from the pedal, just much lower volume than unity.

Edit:
Removed the tone switch and permanently bypassed. Still not working.
Click to expand...
It drops at q3 then?
 
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