Forum dedicated to helping people debug and troubleshoot non-functional pedals or builds. Please use an clear and informative title, indicating circuit and basic problem. Don't forget to mark the issue as fixed if this is the case.
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Debugging 101 General rules and hints to succesfuly bring back that old pedal to life
I have a unit where the Regen knob is going haywire. No matter how much I turn the Regen, it always product endless repeats. Any idea what could be wrong?
I’m building a fuzz face circuit on my breadboard with two BC108 transistors. I have gone over this thing again and again and have checked all the components and they are fine yet I still get no signal out of it. Can anyone take a look at my work and tel me what I did wrong? I would really appreciate it. Thank you.
Hope my questions here won't be too dumb; I'm trying out a couple of circuits on veroboard/tagboard with layouts from the tagboardeffects site, one of these is their Boss SD-1, now I have some soldering/troubleshooting experience (I've built pedals and tube gear before) but I can't seem to make the clipping section of this pedal work; it passes signal fine and the level and tone controls work as they should. But no matter where I put the drive knob it doesn't do anything, I've...
I have constructed a Univibe clone pedal which works on 24 volts DC. I am trying to make it work using a 9 volt DC supply and a charge pump using the LT1054CP Integrated Circuit. I was hoping to get 18 volts out of the charge pump (Road Rage 2019) but it supplies less than 17 volts. (It varies rapidly from 16.5 volts to 16.9 volts). I have measured the voltages around the circuit and I have enclosed them in the attached circuit diagram. I have corrected one ground loop already but I cannot get...
I got a Fulltone OCD v2.0 for repair, the issue is, that the LED is all the time on, no matter where the footswitch or the bypass mode switch are. Also the LED seems to be quite dim. I have opened the box, and saw, that C14 is missing, however I have seen other pix on the internet with that cap missing too. Also I was foolish enough to remove the LED, only to find that it is ok, but I have destroyed a trace and a pad in the process, so I'll have to rework that too... Anyhow, I don't...
Hey all! First time, long time, etc. Was hoping somebody could give me a hand repairing an oldish MojoHand FX Bayou Trem ( ). This is a pedal I've had for a while and haven't had any problems with, but sometime I think in the last move I must have rattled something loose, since it now displays a lot of the classic non functional tremolo symptoms - passes clean signal, volume control works as a clean boost, and rate LED flashes with the rate knob, but no tremolo when the effect is turned on.
I would need help to understand if this pedal that was sold to me, has or not a problem
Basically if I connect in a series guitar amp effect, the mono output has a fairly low volume.
If I plug in the output next to stereo, the volume is ok.
There is a pronounced decrease in volume both in bypass and with the pedal on, the trimmer gain compensates for this drop.
But, as mentioned, the volume on the stereo input is ok.
In case I connect the pedal in loop instead everything seems ok.
The...
Hi, I've just rebuilt a Small Stone phaser from the tagboard layout:
SmallStone.png
and am having some issues tracing the board - I've built one a while ago, so I know that the layout is good, but does anyone have voltages for this particular version of the circuit?
I've had this one for a while, was working perfectly but now i get low output and the effect drops volume when engaged, bypass works, the Chorus/Vib/Trem modes all work but the sound has a very loud bass thump to it.
I've attached a schematic i've found, I suspect the first Transistor because the LFOs all work and the leds behave normally, anything other i need to check just in case ?
Working on an Ibanez AD-80 (narrow box) currently. I’m in the process of replacing a broken diode and just want to make sure this the right part on the schem? Going to replace with a 1N4004.
ibanez1.jpeg
ibanez2.jpeg
Link to schematic:
The pedal powered on (led), but passed no signal. There was one cap that had broke lose from the board and this diode. I re-soldered the cap, and will replace the diode. hopefully this brings it back to life!
I'm working on a Danelectro 3699 (Foxxtone) (layout: 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...
Built out a janglebox using the lm13700 layout and not getting expected behavior.
Getting a mis-biased type sound, with sound only kicking in with louder notes and decay sputtering out then abrupt silence.
Video here:
Pictures of top and bottom of board:
Pins 3 and 4 are giving me an expected voltage reading of about 2.92v with a .02v max differential between them. Pin 1 is 1.31v with attack at max and 1.20v at min.
Issue seems to stem from pin 5. Getting a voltage reading of...
Hi all !
The pedal has no effect when engaged. It also has a big volume drop.
There was a shortcut due the bad shape of the Color switch. I cut the common leads and the ones at the down position and put together.
One of the transistors was dead, I put a bc239 (same pinout as the bc309's.)
I guess I can use ca3094's instead of eh1048 wich are completely impossible to find. Now there are five ic sockets for the op amps.
The ca3094 near the pot area measures 0.70v @ pin 6 with the...
windgabgutz.jpg Hello,
I'm building a VFE Windbag and I'm having an issue.
Everything seems to be working fine, but I get a steep volume drop and a muffled under-the-blanket sound when engaged. If I crank the volume, I can hear everything doing what it's supposed to do delay, reverb, envelope, etc...just at a very low and muffled volume like a hi pass filter.
I checked the voltages, and they are a bit off, but I'm not sure what to do about that. If it matters, I subbed a TL072 for the OPA2134...
i've tried to build this bass preamp explained by Rob Mods ( in the pedal version.
Here's the schematic (also attached):
However, after soldering everything, i don't get an output when I engage the pedal. However, the LED is lighting up (so stomp switch seems to work properly), but don't hear anything (no noise hum, nothing).
When I bypass the pedal, my signal moves through the pedal, so no issues with that.
Does anyone have tips & tricks on how I could start debugging? I have a...
Hi i bought a ibanez cpl compessor really cheap. I new it didnt work well i have checked everything. i cant see anything burnt or broken what its doing is it will pass a signal when the pedal is turned off soon as you turn it on the signal stops. I even put a new ba6110 chip in it didnt do anything doing the same thing got a signal in bypass signal stops when you turn it on. I have checked all the voltages everthing is good. So would anybody have any ideas what is wrong with it. Here is the...
Hi. I've got this Companion labeled Shin-ei fuzz wah, the fuzz works but the wah does not. I've noticed from pictures of other shin-ei fuzz wahs the wiring in mine looks different. The ground is wired directely to the wah pot. Also there is a red capacitor where it's supposed to be green. (not sure if it's a capacitor). Can anyone give me some advice on how to fix? Thanks
Hi all !
The pedal has no effect when engaged. It also has a big volume drop.
There was a shortcut due the bad shape of the Color switch. I cut the common leads and the ones at the down position and put together.
One of the transistors was dead, I put a bc239 (same pinout as the bc309's.)
I guess I can use ca3094's instead of eh1048 wich are completely impossible to find. Now there are five ic sockets for the op amps.
The ca3094 near the pot area measures 0.70v @ pin 6 with the...
I'm moving my post which was initially on the MXR MicroChorus dedicated thread ( here, since it seems to be the proper location for that!
So, long story short:
the MXR MicroChorus uses a SAD512 BBD chip which is hardly sourceable.
Fender3D provided on page 5 a complete rebuild schematic and a PCB in order to use a MN3007 chip instead
Since the original schematic and the updated one are quite close, I just made a small additional board
I basically use my rat between 8 and 8:30 o'clock - or right above zero on the the pot sweep. It is super hard to dial in with the stock design since every micro movement makes a huge difference. This is the only part of the pot range I use, so I'm wondering if there is any modification I can do to get more sweep in this range so that I can use this pedal more easily and so I don't have to spend a few minutes micro dialing it in if the pot moves a smidge?
Hello everybody, so, recently i built Civil War Big Muff clone with schematics from tagboardeffects. All the components that I used have the same values like the ones in the schematics. For transistors i used kt3102em and for diodes kd521a.
First build was not working from start, i was not getting any fuzz, just a slight distortion. I noticed that when i rolled off the sustain (distortion) potentiometer that I would get constant, high pitched buzz (sounding kike synth), after a minutes of...
I am trying to learn how to design PCB with KiCAD. My first attempt is a simple 3PDT breakout board for true bypass. Before I place an order, is anything willing to give my design a sanity check?
Hi,
I'm trying to make an inverting op amp buffer as I want to flip the phase and buffer the signal. I've attached a photo of my breadboard and the circuit I'm trying to follow.
When I connect it all up, the output is super low, -30dB or so from where I started, and it looks like my signal is being low passed. I've tried a few different resistor values from 1M to 10k for both resistors with more or less the same result. Also tried a TL072 op amp, also no luck.
I assume I'm missing something...
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