ac/dc power supply problem ?

I have a problem with acuson X700, when I was press the power on button the machine tries to boot but within 2-3 seconds it shuts down, we found problems in ac/dc power, and after ac/dc repair the machine can not a startup. The AC power supply only shows power light intermittent green, none of the other lights come on, 48V and 12V checked out OK on AC. Also checked the DC-DC TPs: All tested, apparently OK, I looking for a service manual for this model, but x300 service manual will be very helpful to me. I'm living in Brazil and I have noted many mentions of a similar problem in x300 and x700 models if you could give me a suggestion i"m appreciate. Thanks.