Build Your Own Clone Message Board

I get clear sound in bypass but when engaged, i lose sound. Not much experience in electronic troubleshooting. This is my second build with no issues on my first. Willing to test the circuit with guidance. Attaching photos.

Does the LED light when the pedal is engaged?

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Math illiteracy affects seven out of every five people.

I can't get enough minimalism.

+1. That's the first thing to check--make sure the effect circuit is getting power.

I don't see any obvious mistakes, so assuming that the circuit is getting power, I would suggest systematically going through the PCB and re-flowing EVERY solder joint. Only takes 20 minutes or so, and you'd be amazed how often this simple procedure fixes problems like yours. Also check the joints on lugs 5 and 7 of the footswitch, since those are the entry and exit points for the signal path to & from the PCB. The I/O jacks and the rest of the footswitch are OK, since bypass works.

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“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

The LED light does come on when engaged. I checked the switch and see continuity between 4 and 5 when not engaged and 4 & 8 when engaged. As far as reflowing, is that just heating up each joint or desolder and resoldering the joints?

Other way around--4 and 5 when engaged and 4 & 8 when not engaged (i.e. when bypassed).

Also check the 7-8 lug connection in the engaged mode, since this is the processed signal output path from the PCB to the output jack.


Just reheat the joint until the solder melts. Make sure that the solder pad is comletely covered, and the joint should be shiny, smooth & conical in shape. Add a bit more solder to any joints that look "thin"--flat in profile, or if the shape of the eyelet hole is visible through the joint. For any blobby or "domed" joints, you can dab away a bit of the excess solder with a clean solder iron tip.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Sorry, your correct, 4&5 engaged, 4&8 not engaged. Also, I see continuity at 7&8 and 1&2 when engaged. I reflows all joints and still no luck. Is there a way I can isolate the segment that is causing the issue?

looks like this cap might be bridged

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Doh! Stupid Diode

It was the angle of the pic. I checked with my volt meter and it's not connected.

Have you double checked your component placement? You may have an incorrect resistor or cap.

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Math illiteracy affects seven out of every five people.

I can't get enough minimalism.

Thanks for the tip. I checked every resistor and cap, and all of the schematics. it is all per the instructions. How can I test to see if any of the individual components are bad?

It's rarely bad components. I'd reflow some suspect joints. There are some cold looking ones in the middle and some blobby looking ones on the bottom.
This is were patients is important. It'll be worth it when you get a working pedal.

All joints have been reflowed earlier, and that did not fix it. Anyone can tell me how to check the components for issues? That is the only thing left that could be wrong.

Can you post a new photo of the solder side of the PCB? One that is in crystal clear focus and not so grainy? A couple at slightly different angles than just straight down from the top would help. Chances are very high your problem is a soldering issue somewhere.

Once we can rule out the soldering as the problem I would suggest using a signal probe to track down where exactly you're losing the signal.

Begin by probing the following places on the PCB. Once you find where the signal is being lost we can fine tune the probing.

Top & bottom of C1
Bottom of R1
Top of R1 & pin 6 of IC1 (sound will be lower in level)
Pin 7 of IC1 & bottom of C2 (sound at higher level)
Pin 10 of IC1
Pin 8 of IC1 (sound at higher level)
Pin 3 & 1 of IC1
Pin 13 of IC1 (sound at reduced level)
Pin 14 of IC1 (sound at higher level)

_________________
"It’s your soldering."

Three years from now you're going to have the occasional cold joint, happens to the best of us. Did you bias it with your meter?

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Pedal building is like the opposite of sex. All the fun stuff happens before you get in the box.

A Stephen has stated, once solder joint problems have been definitely eliminated--and please forgive our harping on this point, but probably 90% of the problems we see here are solder-related--BY FAR the best way to troubleshoot the circuit is with a SIGNAL TESTER. It allows you to probe various points in the signal path of the circuit and determine where the problem first occurs. You can either purchase one from BYOC or make your own using the instructions on that URL link, since it is a very simple device.

Something else you can do which requires only a multimeter is to take a full set of DC voltage readings around the 14 pins of the IC and report them here. We can compare your readings to those from a working Mimosa, to see if there are any significant differences.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

I'll try the volt meter first then. I do not have a signal tester. I have an analog volt meter. When I test the pins, where am I placing the probes? Is it testing between 1&2, then1&3, etc?

Set the meter to the next higher DC voltage range than 9V, unless it's an auto-ranging meter. The black/negative probe should be on ground (I generally just stick it in one of the four corner screw bosses of the enclosure, assuming the effect is already mounted in it) and then touch the red probe to whatever point you're testing.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Perfect, will do it tonight and give the readings at each pin.

Here are the voltages I got from IC1 and a few other spots.

Power Supply - 9.02V

IC1
1) 4.51
2) 4.51
3) 4.51
4) 9.02
5) 4.51
6) 4.52
7) 4.51
8) 4.94
9) 4.94
10) 4.84
11) 0 (ground)
12) 4.51
13) 4.51
14) 4.50

Right side of R4 - 9.02
Left side of R4 - 4.84 (same is pin 10 of IC1)
Right side of Q1 (Drain) - 9.02
Center of Q1 (Source) - 2.60
Left side of Q1 (Gate) - 1.67
Bottom of R22 - 9.02
Top of R22 - 4.51
Bottom of R8 - 4.51

_________________
"It’s your soldering."

I am not getting these readings at all. Its hard to tell the exact reading since my voltmeter is analog but i can see that approx below.

1. 5.0
2. 3.0
3. 5.0
4. 7.0
5. 4.0
6. 1.5
7. 5.0
8. 9.0
9. 4.0
10. 4.0
11. 0.0
12. 1.0
13. 1.0
14. 5.0

Can you post a photo or two of the face of your meter, so that we can see what you're working with?

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Here is the meter.

Are you setting the meter range to 10DCV and reading the results off the 0 - 10 (bottom) black scale on the meter? You should be able to read the result to a tenth of a volt quite readily that way.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

I am reading the bottom i gave the approx readings since they were so far off from the ones provided.

I'm thinking you have a soldering issue. Pins 5 & 12 of IC1 should be exactly the same because they are both connected together by a trace on the PCB which in turn is connected to the voltage divider (R22 & 23) portion of the circuit.

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"It’s your soldering."