Foxxtone low output

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rtc37
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Post by rtc37 »

I'm working on a Danelectro 3699 (Foxxtone) (layout: https://dirtboxlayouts.blogspot.com/202 ... -fuzz.html) and am testing by running the wiring through a breadboard to pots (which I've mounted directly into the breadboard) which is my usual testing process before boxing. I don't currently have a SPDT switch for the tone so I've jumpered it through the breadboard and same with the octave switch - I haven't wired a DPDT or 3DPT yet. This layout calls for three 50kB pots but I'm currently testing with what I have on hand until I order (50kB, 250kA and 10kB). All pots are set to max for this test.

I'm getting fuzz, the tone and octave work (depending on how I set the jumper for each) but the volume output is extremely quiet but it doesn't sound misbiased like it's farting out. I realized I missed the 2n2 cap so I soldered in a mylar one until I can get a film box one (fits better). I haven't cut the legs off so it kind of looks like a solder bridge in that area of the photo but it's not. I soldered the electro caps in to lay down but have pushed them up for troubleshooting which is why they look weird. I've double checked the positive and negative leads and they're all right and nothing seems to be touching anything it shouldn't be. I'm also using the specific weird resistor values and haven't subbed anything.

With my audio probe and the schematic ( I traced the signal as best as I could figure out and everything sounds fine until Q4. The base and emitter give me sound but the collector is where the signal goes very quiet. Everything after that is also quiet. I found blutack stuck in the socket for the collector so I desoldered and put a new socket in but I still have the same problem. The problem persists with any transistor I use and I test the pinouts with my tester just in case. I also went through a printout of the layout and double checked every resistor, capacitor and diode value to make sure I didn't solder the wrong thing in.

I removed the 22uF cap (output cap?) temporarily and I got a much more audible signal on Q4 collector with my probe.

Voltages

Battery=6.96v

Q1
C) 1.985v
B) 0.664v
E) 0.968mV

Q2
C) 5.24v
B) 1.983v
E) 1.389v

Q3
C) 5.57v
B) 0.663v
E) 93.9mV

Q4
C) 5.96v
B) 0.667v
E) 112.9v

I have cleaned the tracks and used IPA more since these pics but the problem persists. I don’t get continuity where cuts are but if I plug the circuit in to power I was getting really bizarre results where some cuts would beep on either side but they sounded almost like the guitar riff that was looping, every so faintly (amp not turned on). I would run the razor some more and eventually some cuts would start or stop having continuity with the “faint riff” beeping. The cuts and tracks are so cut I can’t imagine it’s making a connection that way. I’m at a total loss. I have reflowed a number of joints but no dice.
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rtc37
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Post by rtc37 »

Problem solved, I noticed voltage on the output and discovered I missed a cut on the third row.

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deltafred
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Post by deltafred »

Thanks for coming back to report what the problem was, not everyone can be bothered.
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