We have a Coby DVD298 player.
We have a consistent problem in that there is no sound while playing DVDs until we either jump up and down on the floor near the unit, tap the front or touch its audio cable.
Sometimes, the sound subsequently cuts out again and we have to follow the steps above.
The video through the HDMI is fine.
All suggestions are appreciated.
Thank you in advance.

If it's hooked up via an optical cable for audio, it's sounds like it's just loose.

If it's hooked up via an optical cable for audio, it's sounds like it's just loose.
Well, we push it into the DVD player and it never seems lose.
We have tried that many times.