Build Your Own Clone Message Board

While not the most common error we see here (that would be poor soldering quality, as Stephen will cheerfully point out!), the following problem description, or something very similar to it, comes up very frequently:

"My pedal works fine with a 9V battery, but won't work with a wall wart/external power supply. The LED doesn't even light up."

This good news is that (1) this problem is almost always caused by a simple wiring mistake, and (2) it is very easily fixed.

The problem arises when the connections for the positive wire of the battery snap and the positive wire to the PCB are switched on the DC jack. It might seem like the two positive connection tabs (the ring and sleeve) of the DC jack would be interchangeable....but they're not. The ring tab (the battery + connection) has a mechanical disconnect inside the DC jack that can deflect and break the connection with the sleeve of the jack, which is what is actually soldered to the PCB + power connection. When a power adapter plug is inserted into the DC jack, the ring tab deflects and disconnects the battery, thereby saving battery life when an external power adapter is being used. While this is a useful feature, if the two + connections on the DC jack are wired backwards, when an adapter plug is inserted into the jack, it disconnects itself!

Take a careful look at the following diagram, which shows the correct wire connections for the DC jack. Note the spatial orientation of the two positive solder tabs--the ring (battery +) tab is closer to the tip (ground connection) tab than the sleeve (adapter +) tab. While this diagram shows the newer style BYOC PCB with the power connections directly to the board, the same rules hold true for the older style, where the DC jack tip (ground) connection is to the ring of the input jack, and the + battery lead connects directly to the ring tab of the DC jack.

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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

Been there, done that. I will print that photo out as well

yep

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Twisting and tinning is for chumps.

I always use this phrase to remind me,

"The battery goes on the inside"

The inside tab or "ring" on the DC Jack
and
The inside "+" on the PCB

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I still do it backwards from time to time.

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

Hi! I'm having a similar issue - just built the Classic Fuzz pedal. First time building a pedal, first time soldering. All went well -- mostly. The pedal works really well when plugged into the DC adapter, but does not work at all on battery power while not plugged into the adapter.

With the pedal in the on position (I know it's the on position because it works with the DC adapter), and only on battery, here are the readings I get when using the multimeter on the - and (+) eyelets, I get 9.6 volts...good. But when when I use it on the - and the + eyelets, I get 400 mV.

Can I assume I should re-solder the + eyelet and then the pedal will work on battery power?

Anything else I should test?

Is it safe to say the battery measures about 9 volts by itself? Check the wiring. If you go in a circle clockwise, you have ground wire the dc wire then battery wire. If you don’t plan on using a battery, I wouldn’t worry too much. I don’t put battery snaps in any of mine, I never use it and they rattle around.


Sent from my iPhone using Tapatalk

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

Thanks! Yes. The 9v is good at 9.6 volts. I checked for continuity from the 9v pads through to the DC jack and all seems well connected. The wiring from the PCB to the DC jack also is good, continuity on those wires.

Any other things I should check? Like you say, not a big deal to not have ability for 9v power, but I want to learn how to figure out why it's not working.

I also. Checked continuity of the switch and the jumpers.

At this point, I'd recommend starting a separate troubleshooting thread so this one can stay more general purpose. Make sure to include photos. Let us know if you need help getting that rolling!

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Scott

My band, Austin Hollow

If I was never planning to use a battery and wanted the pedal to stay powered all of the time regardless of whether a cable was plugged in, is there an easy jump we can make on the board to bypass this feature? Thanks!

Sure. Just connect the wire from the "Ring" eyelet at the top of the PCB to the sleeve tab of the input jack rather than the ring tab.

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

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

Thank you, this is essentially the same as just connecting ring to ground to make the connection, correct? Thanks!

Yes, that's correct. The ring only grounds when a cable is inserted into the input jack and the cable sleeve makes contact with the ring. But the sleeve of the input jack is always grounded.

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

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