Did you use the headers supplied with the Pirate radio? If yes, you can just unplug the pHat Beat from the Pi and swap Pi’s to see if its a Pi Zero issue. Just remove everything from the case. If you soldered the pHat Beat right to the Pi Zero’s male header, please post a screen shot of the soldering. If the two are soldered directly to each other its going to make troubleshooting really tricky. You need to look at the status LED on the working Pi, versus the one that’s not working to see if Raspbian is actually booting up.