Ohhhhh Kay!!

[kaycee]

As you can follow the schematic through, your best bet would be to use an audio probe and trace the signal through with that. Easy and cheap to make and use one, follow the signal through from base and collector of each trans to find where it dies or goes weaker.

Certainly for circuits like fuzz, an audio probe, signal generator, continuity tester and bench amp will find your issue if you can follow a schematic through.

As an aside, I share Iain's love of the BD139 transistor.

[duck_arse]

your transistor voltages look good OK, and your cap voltages are a little hard to follow, circuit reference-wise, but any cap that is attached to ground, or is pulled down to ground via a resistor, will read MUST read 0V on that end. very very VERY difficult to blow a cap from soldering. if your soldering technique is putting that much heat into components, they are probably all dead.

we need to see photos of your board so we can actually make out what is happening on your board [and the state of those caps!]. and we need to see all off-board wires, to check you aren't using the pot-rivet holes, or like that. please.

[francis1978]

ok, so I successfully built an audio probe. Yes, I wrote successfully because I built a circuit tester and it ain't working but I suspect is the DC power jack...

Anyway, probing the circuit, I get signal (high continuous "pitch") from Q3 (collector / base pins) to cap after diode 2.  Everything else surrounding that part of the circuit is dead thought power gets thru.  The is no audio from input jack either although signal gets thru when bypassed.

Makes me wonder if the true bypass switch wiring isn't' killing the sound at input when the circuit is engaged

Pictures will come later!

[iainpunk]

Anyway, probing the circuit, I get signal (high continuous "pitch") from Q3 (collector / base pins)

would be nice if we actually knew which transistor is Q3, do you have the schematic of which you build this?
is this high continuous pitch from outside the pedal, or does the circuit produce that?

diode 2

i suppose that its one of the clipping diodes?

so i gather from this that there is no signal getting in to the filter section. correct?

cheers, Iain

[francis1978]

a little update (..)

I bought one those USB microscope to check for any microscopic bridges between the tracks (stripboard) and probed the circuit again.
Now, there is a white noise passed Q1 up to Q3 and there is signal (squeal) up to the cap after the 2nd diode (like before)
Touching the components elsewhere creates a "cracking' noise that last less than a second but nothing (no noise/signal).

I also probe the input jack (nothing) with and without some music going thru.
With music there is no signal, Can I assume that I should hear a signal?
Without music, probe the jack, mono cable inserted and test for continuity as described in this post
https://www.diystompboxes.com/smfforum/index.php?topic=105011.0
Tip tested fine. With ground at the non-inserted jack both sleeve and ground tested also fine.
at first I thought the sleeve and ground (on the jack) where shorted but since I was using a mono cable that reading is perhaps correct.

Probe the switch (ON) for continuity is look fine.
I don't know why I keep thinking that it's the way I wired the switch that kills the audio.  but if signal goes thru when in bypassed mode then it must be something else.

Schematics and drawing are on my previous post
As for pictures, I'm sorting them.  That USB microscope is quiet handy!

Disappointment and annoyance is slowly taking over my frustration... hehe

[iainpunk]

I also probe the input jack (nothing) with and without some music going thru.
With music there is no signal, Can I assume that I should hear a signal?

yes you absolutely should.

do you have (atleast decent quality) pictures of your build, that would help us a bunch.

it might be that the switch is wired wrong, or turned 90 degrees or something in that range, you might want to test the circuit without the switch, just without bypass, just to check if the circuit itself is broken or not.

cheers, Iain

[francis1978]

Hi,

(this post originally written on Dec 28 has been modified in its entirety - here is the new version)

Current status
- Signal is going in fine from input jack to IN on the circuit - so this means the IN jack and switch are good and their wiring are ok
- I untwisted the IN/OUT wires going to the circuit as well as the wires going to the POT - I think that helped a little

Issues:
- The incoming audio going thru the first resistor (22K) gets quiet at exit (before entering the 10uF cap / see first red square to the right on the board pic) - I suspect a faulty resistor although I find it strange as I'd believe this should also impact power but who knows...
- So, in order to hear signal, I increased the volume of the income signal (luckily I am probing with music thru my focusrite preamp)
- Signal goes thru normal up to T1. I also probe the T1 Pot leg - signal heard is fuzzy and seems to be octave down)
- T2 has not signal (nothing on the T2 pot leg as well), and subsequently, cap and resistors wire to T2 has no signal. The 10K resistor has signal coming (from 22K resistor) but has not signal on the other end, the part 'wired" to T2
- Consequently, no signal goes to trimmer and therefore no output - Am I correct to suspect a faulty POT?

I did some readings on the POT and although is its a 100K Lin, it only goes from 0 to about 40ish. Fully rotate and reading 0 the signal cuts off. I though the purpose of having the 200K resistor was to avoid the signal to cut...

Notes:
- the second red square on the board is a place where I initially made a cut by mistake. I fix it with some copper tape. Seems to be ok but I am hesitating if I should just desolder all the components and rebuild the circuit using a new stripboard, what are your thoughts?

Since things seem to have improved a little, i will check the schematics and the layout wish fresh eyes tomorrow...

thanks for your patience!

[francis1978]

Solved!!

FYI
The main issue was the outgoing signal from pot 2 which was going to ground and as such it wasn't reaching the trimmer to output.
Once I corrected this mistake everything went great.

The signal still drops after the 22k resistor (Input) but the output buffer compensates for this loss.

After the fix, I plugged the pedal to my audio interface. At first I was a bit down because the bypass signal (clean) was louder than the effect when engaged.
i rotated the trimmer (it's a multiturn pne) but nothing happened yet the signal did increase but wasn't at gain unity with the clean one.

Then later on, I plugged the pedal to the Send/Return  of my GT-10 and bloody hell!! the fuzz was loud!!!
it works!!

Now I just have to open the enclosure to set the trimmer at a comfortable level once for all.

thank you all for your wisdoms and patience!

Wish you all a great 2021!

Now next project, perhaps a FA-1 or a treble boost


** Sorry I couldn't delete the previous post, I wish there was a delete button **

[PRR]

..... I plugged the pedal to my audio interface. At first I was a bit down because the bypass signal (clean) was louder than the effect when engaged..... Then later on, I plugged the pedal to the Send/Return  of my GT-10 and bloody hell!! the fuzz was loud!!!

"Audio interface" can be many things. But a lot of them are 22k input loading.

GUITAR inputs are 220K, 470K, or more.

Are you using the plan in post #10 of this thread?


The output section is all 10k, 22k, 100k or so. This will give some or a lot of loss driving a 22k input.

Also "line input" is 770 milliVolts, maybe 200mV cranked. A guitar can make this much, but we are accustomed to guitar inputs that can be maxxed with a mere 20mV (for easy overload).

** Sorry I couldn't delete the previous post, I wish there was a delete button **

You have some short time to edit (or delete) your words.

Mostly, here, we don't try to re-write the past.

If you have posted something horribly embarrassing, use the "Report to moderator" bottom-right of your post. Say you want your post deleted and Aron will do it (when he has time).

[iainpunk]

nice to hear that it works, audio interfaces can make things sound more similar in volume since some have compressor/limiter in them.

cheers, Iain