Open your coin door and you should see a switch with two positions. To put the machine in test mode, put the switch in the down position. Up position is for game mode. Turn the machine on, and after about seven seconds you should hear a series of beeps. I believe there are 16 beeps total if I remember correctly. High tone beeps are good, and low tone beeps are bad. If you have bad chips, you will hear a low tone during the series of beeps as well as see an error message on the screen during the test indicating which chip is bad and where it is located on your board. I recently had to replace one of my VGRAM chips on the video board. The error message I got was something like "BAD VGRAM2 AT 3C". This was a 2016 SRAM chip and was causing the fireballs to look messed up. Replacing this SRAM module fixed my problem. I got a replacement from twistywristarcade.com. Please post the results of your hardware test and let us know what the error message says, and we'll try to help you.