@roboscrap, If it works, with 1.5A, when it was designed to operate with 3A, it’s 100% not going to operate optimally!
In order for the unit to function as designed in all situations, you need a PSU that’s capable of delivering at least 3A. Running it with a PSU with less power could very well be destroying the device, as it’s trying to utilize more power than it can possibly get.
An analogy is: You can lift a max of 100lbs, but to operate your job it is required that you lift 200lbs. You try to lift it, and you can possibly slightly move the weight, but in the long run you’re simply destroying yourself in trying. (NB! The human body would grow, and the more you tried, the better you’d get at it. Electronics does not work that way.)