Despite being very careful, I partially pulled the surface mounted battery cable socket off the circuit board, slightly; not apparant at first, but enough to cause a similar problem. Re-soldering is not possible without special tools. That socketccalles for careful and delicate technique. I used the tip of an X-acto knive, very carefully, to JUST lift the retainer clip slightly; freeing the cable.
Also, ensure thsat the cable for the HD is inserted correctly. Reversed, can cause issues akin to the above. View videos at sites like this one.