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If I have the mule going into the kicker I just get high pitched squealing, no guitar sound at all. But having the kicker going into the mule everything works. What could be the problem?
- Does each circuit work independently with the order switch in either position? (Provide details)
- Is the power supply being used 9v and capable of at least 30mA?
- Did you make any part, or value substitutions?
- Is the capacitor used in position C13 a ceramic or a tantalum type?
- Do you have a RC4558D chip similar to all of the others used to try in IC1?
Both circuits work independently and together only when the kicker is boosting the mule. If the mule is set to boost the kicker then there no sound from the kicker and a high pitched squeal from the mule. Also there is no sound from either circuit in by pass mode.
The power supply is 9v and capable of much higher than 30mA. There were no part substitutions. I have 7 RC4558D and RC4558P chips, tried both but still no change.
Just to clarify, when you say there’s no sound in bypass, do you mean you’re still hearing the guitar signal as expected in bypass mode, or nothing at all?
Is the capacitor used in position C13 a ceramic or a tantalum type?
Note: If both circuits function correctly on their own—including both active and bypass modes (i.e., you’re getting clean bypassed guitar signal)—then the issue is likely not within the individual circuit components themselves. The first thing I would check is the order switch. It may need a quick re-flow, but keep in mind that these switches are sensitive to heat and can be easily damaged if overheated during soldering, so that’s something to consider.
The C13 is a MLCC. Everything works as it should if the order switch is set to have the kicker boosting the mule. When both circuits are in by pass mode (off) and flip the switch to the right putting the mule boosting the kicker there is no clean guitar sound, no sound at all. If I put the kicker on there is no sound. If I put the mule on and start turning the volume than I get a high pitched sound. I also changed the order switch and there was no change. Someone please solve this issue. Thanks.
So as I now understand both circuits are dead when the order switcher is flipped to the right. Regardless of ACTIVE or BYPASS. Squealing doesn’t count as functioning.
So again just to clarify (it is important), both circuits function normally whether they are used in tandem, or independently, and also produce clean guitar sound when bypassed as long as the order switch is flipped to the left.
Note that we have to completely understand what is going on since this is not normal, and we are basically trying to help you troubleshoot online without the ability to have a hands on approach.
I just downloaded the PCB image and noticed many questionable solder joints.
I suggest a complete board re-flow. The pads need to be filled in on every joint.
Have some solder handy and while working from the backside of the PCB touch your iron to every joint (suspect or not) to re-flow it. When a pad is questionable add some solder to it. You do not want a huge blob of solder but just enough to melt into the pad.
Here are just a few of the questionable solder joints I found when I zoomed in but re-flow the entire PCB (every component joint). There should be no spaces in the pads. Since you will need to bend the potentiometers back to get at them do so carefully with as few repeated bends as possible. Take your time. Then after you have re-flowed the entire components of the PCB and bend the pots back into position you will then need a light re-flow on every potentiometer because bending them will weaken the existing solder joint. A quick re-flow will fix that.
The difference between too much and just right.
All your component values and orientation that I can see look correct I can’t see R15, 16 and 17 completely
As Barry said some of your joints do look potentially dry it’s difficult to tell with the reflection
A3 on the order switch looks like it may have a poor connection
Thanks for that answer.
The issue may be due to an intermittent connection. A full reflow of all solder joints should help resolve this and also prevent potential future issues in any weak areas. Given the size of the PCB and number of components, a careful reflow should take less than 10 minutes. Just be sure not to repeatedly bend the potentiometers more than necessary. Once you’re finished and have repositioned them, it’s a good idea to do a quick reflow on all of the potentiometer solder joints to ensure a solid connection to finish it off. As Billy mentioned reflow the switch as well.
I have done everything that has been suggested, even cleaned the pcb with alcohol .It still does not work. To me it is looking like there is a problem with the pcb.I have been putting pedal kits together for about 15 years now. I know how to do it. I will keep messing around with it. Please keep making suggestions. Thanks Barry and all that are trying to help.
Thanks for the update. I still highly doubt there’s anything wrong with the PCB unless there was visible physical damage, which should be apparent.
For context, I’ve personally built and verified this circuit before its release, and also assembled another unit that was sold to a friend without issue. Additionally, another builder has successfully completed one, which you can see here:
https://guitarpcb.com/community/topic/mule-kicker-pro-completed/These are all from the same production batch.
At this point, please upload clear photos of the solder side and a new Top side photo of the PCB. Since we’re supporting you remotely, we have to rely entirely on what we can see and what you describe—so detailed visuals are essential for spotting subtle issues like cold joints, bridges, etc.
I’ve been building for 20 years and still make mistakes, it’s easily done
Continuity check your order switch connects as it should in both positions ie with fx1 first then fx2
From your description with both circuits working independently it does sound like an order switching problem one switch position works the other appears to not work why idk
Continuity checking all 3 switch connections will hopefully reveal the answer
I checked the continuity of the order switch and there is no continuity from lug B1 and FX1 out. Also i am getting continuity from FX2 output and C1,C2 andC3.
We still need photos to see what we can discover.
For now post a closeup, clear photo of the 6 connector pads on the Klon side of the main PCB Top and Bottom, and the 3PDT wiring board Top and Bottom. Make sure all 6 pads are visible with no shadows.
So this complete section, both sides, but clear with no shadows.
We may need a couple more later but lets start with that.
FYI: I will be out the rest of the day. That said my status is always online.
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