I got excited to find this thread only to discover that my printer is on 70 so it has the latest board already. It's also on the latest firmware which hasn't been updated in years.
I've bought multiple toners from different vendors and I keep getting issues with it streaking. If you replace the toner it goes away but the problem keeps coming back. I'm not sure I want to waste any more money on the HVPS or ETB. It's probably cost effective to replace the unit at this point.