Does not power up, magsafe green, fan and usb power every 5 seconds

Hi,

Have a Macbook 2012 13”

Does not power up, magsafe green, fan and usb power every 5 seconds (for less than a second)

I’ve tried every key combo, but no display. I’ve blown out the dust. I think a voltage circuit might be toast? I plugged in a usb fan and just like the exhaust fan, when it’s plugged in, both fans fire up every 5 seconds or so. Possible to fix without replacing the logic board?

Thanks