found this little note
"Slow flashing front LED , on screen high definition player only displayed.
Short on 12V supply on the HDD. Faulty HDD " if you get a short across the 12 or 5 volt line, its always worth checking the smd diodes on the PCB, I've had these go quite a few times and it a nice easy fix.
The most common HDD i find this failure on is the Western Digital ones,it is usually one of the black sm diodes onboard the HDD firmware pcb,a general purpose diode does the job