YLOD -RED LIGHTof DEATH??

Okay so I have done a few ylod repairs but today I was repairing 2 ps3s and they both seemed to have the YLOD, after doing the repair on both of these systems i attempted to turn them on. They both seem to have the same problem, i hit the button it turns green for 2 seconds then a red light comes on, then you here it beep twice and power down with a flashing red light.

Can anyone tell me what the problem is? I dont think its the HDD as i have already tried alternating between 2 HDDs. and I have already done the YLOD repair.