Power supply question

[polaraligned]

Measure the voltage when machine is running. I would bet the machine is pulling more current than the supply can reasonably deliver, so the voltage is being pulled down.

[SLK001]

Any ideas why this isn't sufficient power?
Thanks

Probably a power supply that is specified at levels greater than it is capable of making. Is the 7A supply a switcher (is it really heavy, or light)?

[challenger]

I have a tennis ball machine that I purchased a power supply for. The machine is supposed to be battery powered by a 12v 7ah battery. The battery went bad and it's convenient for me to use a cord. I ran the battery wires outside of the unit and powered it with a 4amp,old style, battery charger and it worked fine. I ordered a 7amp power supply and the unit runs but the low battery light glows and the feed tray won't rotate. Any ideas why this isn't sufficient power?
Thanks