Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
Something in the data train that leads to the speakers, from the QD disc(s) it-/them-selves, is interrupted.
Perhaps the read heads are a trifle corrupted with oxide or dirt? cleaning the read heads in any floppy-disk-type drive is standard maintenance, since the heads rest against the floppy disc surface and scrape off ferrite coating over time.
But there are also other possible faults, which could be in the data path as I said. Double-check that putting the new drive belt in did not disconnect or disrupt any connection!
And then, unfortunately, you might need circuitry repairs in the drive.
But first, before pronouncing any final opinion, I would need to know:
- What was the original problem with the QD drive that caused you to replace the belt in it?