Maybe this helps
Ok maybe I can help you. My D60 did the same thing. Turn it off. I turned it over and opened it completely up. You will have to remove several screws. Turn it back on. Get a power tester and touch around, with it grounded, to random souldered joints. If it turns on, you can find out if the break in the power is in your power supply board or not. Mine was. For a while I left my machine on at all times because if I turned it off it would not come back on again without this whole process. I called Summa and they told me I could send it to them, but the cost involved, was not worth putting into a D60 of 6 years old. I took the chance confidently knowing that I could replace it. I did and it solved the problem. Since then I have replaced the head as well. The PS cost about $200.00, where the head was $3-$400. Dude walked me through it replacing the head and as any of you know it is still strong as ever. I hope that helps. Give me a holler if I can help any further.