I bought an arachnid top gun dart game. The owner had it in storage and assured me that it worked. I had no way of testing it. Got it home and of course it will not come on. The power supply, switching type is making a buzzing noise. The 12v lead is reading low around 10v and the 5v is reading 3v. So I assumed a bad power supply, but then I noticed when I unhooked the main board the buzzing stops and I get the right volts. 12vs and 5vs. My question is should a power supply be tested under a load. I also tried using a computer power supply, but I think it has too many amps. The main board started getting hot so I pulled the cord. I don’t want to spend money buying the wrong part. Thanks.