Pi Zero won't power up with Phat DAC


I’m having some problems with my newly acquired pHAT DAC. When I connect it to my Pi Zero, the Pi completely refuses to power up. The Pi powers up on its own, and also if I attach another hat (JustBoom Amp Zero).

I suspect the problem is either my beginner-level soldering (my first ever attempt) or that there’s something wrong with the pHAT DAC.

Any ideas / suggestions?


What power supply are you using? How much current does it supply?

I would try an alternative one first, as if it’s not a strong one then it may not provide enough juice to run everything together.


Could you post a picture of your soldering?


I’ve tried three different power supplies - one of them being an official RS Components Raspberry pi power supply.


I’ll try and take one when I get home later on. It’ll give you a laugh if nothing else.


Here is the butchery that I committed to the Phat DAC

Is there any hope for it?


I suspect the possible short between 5v and 3.3v might be your problem.

Without adding any more solder, just touch the tip of your iron to each joint and hold it there for a couple of seconds until the solder forms a neat cone- like a volcano- around the pin.

And watch this: https://www.youtube.com/watch?v=K5zrgEDsxSQ

It really helped me grok the rhythm and technique of soldering… although the video is getting a little dated now!


Thanks for the swift reply. I’ll give that a go and see how I get on.


There’s a couple of other shorts which would also benefit from the same treatment.

The key thing about soldering is that the iron is to heat things up, not to paint solder on. Don’t use too much, but make sure there is some on the iron (it is “tinned”) to get good thermal contact to the pins or whatever.

Warm everything up, then apply the solder and let it flow and make the joint. Use enough to make a nice smooth one, but don’t overdo it. Less is definitely more here.


With your advice, I managed to patch up my dodgy soldering. It’s all working as it should now. Thank you!