SOLVED First BUILD - Failure

[JDJudd]

Hi all - thanks for your encouragement and help as I embarked on my first pedal build.

I grabbed, PedalPCBs Mahayana Drive (Zendrive) and followed the guides available in this forum. I also followed The Tone Geek's video of his build of this same PCB.

I ordered the wrong potentiometers with my initial Tayda order, so after waiting for the right parts to show up and finishing my wiring, I was SUPER excited to try this thing out.

... but ... nothing.

Here's the gutshot:



What do you notice that I've done wrong?

 

[BuddytheReow]

Does signal come through when bypassed?

 

[JDJudd]

Yes. Signal is loud and clear on bypass. Total signal loss when pedal is engaged.

 

[Barry]

Lots of those solder joints look cold

 

[BuddytheReow]

Does it get power? Check voltages on the IC legs

 

[Nostradoomus]

Could be a cold solder joint. Some of your joints look pretty cold on the top side, can we see the bottom?

 

[JDJudd]

No power to the IC.

Here’s the underside

 

[JDJudd]

Could be a cold solder joint. Some of your joints look pretty cold on the top side, can we see the bottom?

View attachment 7434

Thanks for sharing this. Any recommendations for diagnosing/fixing cold joints?

 

[Barry]

Use the pictures provided, anything that looks other than the ones that say ok reflow

 

[twebb6778]

Is your LED lighting up? If you're getting 0v on pin 8 of your IC there could be an issue with the power.

 

[JDJudd]

No LED

 

[JDJudd]

Removed pots and wiring so you can see the board better.

 

[Nostradoomus]

What are you powering it with?

Any joint that looks suspect, just hold your iron on it until you see the solder transfer down to the pad smoothly. (Should only take 2-3 seconds depending on the temp of your iron)

 

[JDJudd]

9v battery.
Reflowing as I type this.

 

[Nostradoomus]

Can we see the power connections?

Also you may want to use both hands

 

[JDJudd]

I snipped the power leads to get at my board more accurately.

Do these solder joints look any better?


I think they do, but I thought my first joints were ok too.

 

[twebb6778]

Those are definitely looking better.

If you're not getting any power to the LED there's something stopping your power getting through immediately. It could have been as simple as a cold joint, but let us know how you go after it wired up again. If it's still there you might have an issue with the battery, the wires your using, short, or a damaged trace.

 

[JDJudd]

Reflowed, rewired and still nothing. No LED, no signal when engaged, signal is fine when bypassed.

I’ve got power to diode at the top, but nothing to the IC.

Here’s a pic of the power wiring:

 

[Robert]

Are you sure the polarity of that 9V battery adapter is correct?

Do you measure 9V on both ends of the diode, or only one end?

This sounds like it might be a reverse polarity situation.

 

[JDJudd]

Are you sure the polarity of that 9V battery adapter is correct?

Do you measure 9V on both ends of the diode, or only one end?

This sounds like it might be a reverse polarity situation

Didn’t even think of that. I’ve got a different adapter I’ll throw on there and see what happens.

not sure about the diode reading. I’ll check it again and report the findings.
Thanks!!!

Are you sure the polarity of that 9V battery adapter is correct?

Do you measure 9V on both ends of the diode, or only one end?

This sounds like it might be a reverse polarity situation.

POLARITY! That was it.

Thanks for the assist. Just played some solos through my first pedal build. Sounds better than I expected.

THANKS EVERYONE!