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Messages - neiltheseal

Tech Help - Projects Page / Re: Skoolie IC3
September 18, 2023, 12:48:20 PM
Quote from: TF2112 on September 15, 2023, 05:59:45 PM
Having the same issue 14v on 1,2 like .4v on 3 what did you do to make yours work?

Hey. I did nothing special. I went through the schematic checking continuity with each part and that I used the correct parts.

I think I had an ic backwards and an electrolytic capacitor the wrong way.

Worth the effort. Love this pedal. Even got it to self oscillate by playing with the trimpots.
Tech Help - Projects Page / Re: Skoolie IC3
August 09, 2023, 10:13:05 AM
I managed to get mine working and it sounds pretty good.

The voltage on ic3 is still off however but it works fine. Although I can't get it to go into self oscillation. I wonder if these are connected somehow.
Tech Help - Projects Page / Re: Skoolie IC3
July 13, 2023, 12:29:07 PM
Quote from: geekmacdaddy on May 01, 2023, 06:07:59 PM
Hey Ya'lls
I'm getting signal into that "stress" LED, but no sound when blend is all the way delay...getting some analog noise (normal amount) when engaged. The beginnings of my problems start at IC3 pins 1, 2, and 3. 1 and 2 are somewhere north of 14v and 3 is jumping around. 4 is zero, 5, 6, and 7 are at 7.5, and 8 is 15.07...the A side of IC3. Any and all ideas are appreciated.

Hey how did you go with this?

I just built the Skoolie and am having similar problems to you. My voltages on IC3 are roughly the same as yours. Pins 1 and 2 are around 14v but my pin 3 is about 0.4v.

Would be great to hear how you have gone with this and hopefully can share how you fixed it.

After all of my trouble shooting, I plugged the pedal in to see if one of my half-baked ideas would work...and the pedal worked as it should.

My half-baked idea was not the fix, I think it may have been a glob of solder I dislodged while continuity testing.

Anyway, I got it going and an quite happy with it. I might have to do a build report.
I've continued trying to find the source of the problem. I did some continuity testing around the problem area, but it seems there is continuity everywhere there should be.

Here is a picture, yellow indicates continuity (please ignore my hand written notes).

Since everything is connected, would the issue be a faulty part? It seems to me there is too much voltage around q4 and not enough around q3-5. I'm guessing there is an issue preventing the voltage from q4 from getting to q3 and q5. Does anyone know why this might be?
I took some voltages and this seems to confirm that the problem is around q3-q5


  • E - 1.71
  • B - 1.38
  • C - 8.58


  • E - 1.82
  • B - 1.99
  • C - 7.45


  • E - 0
  • B - .07
  • C- 9.1


  • E - 8.45
  • B - 8.95
  • C - 9.07


  • E - 0
  • B - 0
  • C - 8.95


  • 1 - 1.3
  • 2 - .07
  • 3- 4.71
  • 4 - 4.71
  • 5 - 1.95
  • 6 - 0
  • 7 - 0
  • 8 - .04
  • 9 - .02
  • 10 - 0
  • 11 - 8.96
  • 12 .07
  • 13 - 0
  • 14 - 0
  • 15 - .09
  • 16 - .07
Here are some pics of the PCB
Hello again, I'm back with another issue that I'm struggling with. Can anyone help please?

I recently built the Keepressor (Keely compressor from PCB Guitar Mania). (build docs

The pedal "works" but not like I had expected. I built a dyna comp which compresses like I expect it to. This Keepressor is very subtle

With an audio probe I have found something that might be an issue, although Im not sure what do do about this.

The signal seems pretty strong up to the base of q3. When I touch many of the parts after this I get signal for an instant which disappears.

D3 - the signal is fine on the cathode.
D4 - signal for a moment on the cathode
Q3 - signal fine on the base, distorted and metallic signal on collector
Q5 - signal on base for a moment, distorted and metallic, but consistent signal on collector
R20 - signal disappears
R21 - Signal fine on one end (connected to pin 3 volume), but on the ohter side same problem as above.
C12 and C13 - Signal disappears

I have checked all of the parts (twice) and they are correct. Transistors and capacitors are oriented correctly.

I had the c5 issue mentioned in the build docs but have fixe this. Once fixed the pedal now works and definitely compresses. The issue is that it is really subtle and most knobs don't audibly do that much.

The pedal sounds ok, but it's a bit of a waste of a compressor at the moment as it is barely noticable. Not like the dyna comp which is very in your face at hight settings.

VOLUME: At full volume the pedal is about unity volume.
ATTACK: turned fully CCW has a mild overdrive sound, that I quite like. Compresses slightly more CCW.
SUSTAIN: seems to work like the sensitivity on a Dyna comp, although it only compresses about 1/4 of a Dyna comp
CLIP: I have no idea what clip does, except for a mild volume boost.

Quote from: NorthCoast on March 08, 2023, 07:25:57 PM
It looks like you used a pair of B2K pots where there should be B25K pots.

Take a look at the intensity and throb controls.

Also, be careful bending the legs of the pots, after 5-10 wiggles back and forth, they'll break.

Hey as an update. You were completely right, it was the pots that were the issue.

I put a 25kb in the throb control and a 50kb in the intensity and it works great. Thanks for picking this up. I can't believe I missed it.

I know the build docs say 25kb for intensity but I only had a 50kb. It sounds pretty good when I tested it so figured I'd leave it. Tacked a 50k resistor from lugs 1 and 3 (which I think should bring the pot down to close enough to 20k) but I couldn't really tell the difference so just went with the 50k pot.
Hi again

I recently put together a Total Bender from PCB Guitar Mania which is 3 tone benders in 1. I managed to get it working with mk3 as a PNP. Link to previous post (

However I have managed to break it and am hoping that someone can assist.

There was too much pressure on the fuzz pot so it only worked at around 10% and 100%. I reflowed solder on the legs of the pot and pushed it out to relieve pressure, however I think i removed the PCB trace rings around the pot so the connection is poor.

An audio signal does come out but it is very faint. An audio probe shows that the fuzz pot is the likely culprit as the audio signal is great until c3.5 on the schematic which is just before the fuzz pot. The signal on fuzz pot and q3 is very quiet.


To repair this, would i essentially solder jumpers from the 3 legs of the fuzz pot to the relevant components? I.e.:
- leg 1 to c3.5
- leg 2 to base of q2
leg 3 to positive end of d1?

Below are pics of the schematic and the PCB. I tried to solder jumpers as discussed but I think i got the legs wrong on the pot. It now does not work at all. Is it 1,2,3 from left to right with the pot facing you?

Also does it matter which leg of c3.5 I solder leg 1 of the fuzz pot to?

Further on the schematic i see d1 and base of q3 are connected. Could I solder leg 3 of the fuzz pot to either of these?
Damn you are completely right! I checked everything else but missed the pots. Hopefully I have some 25k around.

Thanks for that.

Yes I did realise after bending for the picture that it looked a little unstable.
Hello again.

With this forum's help with my previous posts I have successfully completed and/or troubleshooted quite a few pedals.

I was feeling confident however, I have run into an issue with the submarine device by PCB Guitar Mania. I hope that someone can assist with this as I'm a little stumped.

The problem

The pedal sort of works.

  • Works in bypass and when engaged.
  • The volume and voice pot affect the signal as does the switch. I can see the little LED change colour and intensity when the switch/voice pot is adjusted.
  • The switch and voice pots audibly affect the signal
  • However the LED does not throb as I assume it should. The rate, intense and throb pots do not affect the signal

I have checked all of the parts (resistors, capacitors and electro capacitors) and they are correct. ICs and transistors are correct and are placed correctly per the provided build docs. This is assuming the letters at the end of IC names mean nothing. I have TL074CN instead of TL074 and TL072CP instead of TL072.

Pics of both sides of the PCB and my audio probe can be found here (

There seem to be a lot of gaps in the audio probe:
- R3, 4, 7, 8, 10 and 11 and C2, 6 and 7 only had sound on one side.
- VR 2 had audio on one leg but none of the other light dependent resistors had an audio signal. Is this normal?
- The signal seems to come out of pin 1 on IC 2 but I cannot see where it goes in.
- The bottom half of the schematic does not have an audio signal at all but this seems correct.
- I can get the voice pot to adjust the brightness of the red/green LED and the switch changes the colour but I can't get it to throb.

I will reflow solder on all parts tomorrow and see how that goes.

Thanks in advance!

Link to build docs:

Voltage (not sure if it helps):

IC1 - TL072CP
1 - 4.61
2 - 4.61
3 - 2.16
4 - 0
5 - 4.02
6 - 4.61
7 - 4.63
8 - 9.28

IC2 (TL074CN)

1 -  4.84    8 - 4.59
2 -  4.64    9 -  4.61
3 -  4.59    10 - 4.58
4 -  9.28    11 - 0
5 -  3.58    12 - 4.58
6 -  4.61    13 - 4.61
7 - 4.62     14 - 4.61

Q1 (MPSA18)

C - 2.08
B - 0.59
E - 0

Q2 (MPSA18)

C - 1.48
B - 0.89
E - 0.23
Quote from: scotheath on February 13, 2023, 07:36:12 PM
I had the exact same problem with a Tayda MK3 build. With the help on this forum I got it going.
What's the volts at collector of Q1? needs to be 4.5v +-

Hey thanks. I actually did find this post and followed the tips but no luck unfortunately. This post (and this forum) helped me get a tayda tone bender mk2 working.

I ended up changing it to germanium and it works perfectly now.
Quote from: mauman on February 11, 2023, 03:48:51 PM
OK, let's give this a shot. Since 2/3 of the pedal is working, that's a good start, you've got power, in/out connectivity, and the 1:3 selector switch is working.  You've also got SOME sound out of this third section, it's just gating when your input signal is low level. 

Starting with the basics:
1. Are the transistors installed with the E, B and C in the proper holes?
2. Do you have this section's DIP switch set correctly for +9V power since these are NPN?
3. What are the voltages at each pin for each of the transistors?
4. Have you tried swapping out the transistors with spares?
5. If all that's good, I think I'd undo the mods and start with the straight build recommended by the PCB maker. When you get it working with the stock build, then you can add mods, and if one doesn't work, you'll know what did it.

Let us know!

Hi thanks for your response.

I followed your steps but still couldn't get it working as silicon. I did an audio probe be and the signal made it all the way to the base of q3.

I did try the pcb as the designer stated initially and it didn't work. The mods came about as suggestions to help get this working. And the mods helped. There was no sound initially.

For voltage :q3 collector is 4.27v, base is now 0.16v and emitter is 0v.

I tried my best to bias q3 with a pot but no luck really.

Some people suggest that perhaps the pcb was poorly designed...I'm not really qualified to comment but it seems to be the case.


I removed the parts and set up the pcb to be PNP. I tested it out with whatever PNP transistors I had lying Aryan's it worked. Not well but it worked.

I ended up buying matched germanium transistors and it works perfectly now.

This is a good outcome as I now can switch between germanium and silicon. The mi3 Germanium is now my favourite but it might be confirmation bias.
Hi everyone. I hope this is the right spot to post this

I just put together a Total bender from PCB Guitar mania. I have managed to get the Mk1 and Mk2 working but am having trouble with the Mk3. I'm hoping someone can help.

This is the silicon version and in the Mk3 transistors are 2n3904.

Currently I can get a very faint signal out of the Mk3 which seems to go to full volume and sound normal when I strum the guitar really hard. Below is a video.

I have asked around and the consensus seems to be that there is an issue with this PCB at least with the Silicon version. I have checked all of the parts are correct and re flowed solder etch and it all seems correct. Plus it sort of works.

Does anybody know what might be the issue here?

Build docs here


- Someone in a facebook group suggested I put a 100nf capacitor in c3.4 where the build docs said to put a jumper. This has helped somewhat and now I get an audio signal (before that there was nothing)
- I put r3.7 (10k) in when the build docs say leave blank as this was in the original schematic.
- Removed c3.9 (470p) as this was not in the original schematic (although I just clipped the capacitor out and didn't remove the legs.
- Reversed the diode (d1) next to q3. I did this because comparing NPN and PNP schematics that they were reversed. My soldering here is bad I know.

For q3 voltage, flipping the diode, adding 10k resistor and removing the capcitor had an effect.
- Previous voltage was: collector is 8.48v, base is now -0.01v and emitter is 0v.
- Current voltage: Collector 4.27, base is 0.16 and emitter is 0

Here are some pics

Thanks in advance!