Question about waveshare pwm hat and power draw

Anyone here have experience with the waveshare clone of the adafruit pca9685 pwm controller hat for pi?

I have 12 servos hooked up with a 5V/20Amax supply direct to the terminal.

Pi is powered by its own 1a power bank via usb

It’s mounted on a pi zero via a 40 pin hat header.

When I put power into the pi, whether the servo power is connected or not, the servos chunter over and over like they’re trying to do the startup jerk but can’t and the pi never powers up. Without the driver connected, or with the driver connected without servos, it will start up fine.

This feels indicative of the driver trying to suck all of the servo power through the pi power rails and not the terminal.

Anybody have any knowledge or experience to share?

Thanks

submitted by /u/RizzoTheSmall
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