🚀 go-pugleaf

      The person who installed the new Hard Drive is a very good friend of mine.




My wife is a very good friend of mine, but she's the last person I'd get to install a HD!

      Is there anything that might cause a DC offset apart from a damaged sound
      card?




A damaged MD recorder could do this as well, but I agree with MusicConductor - sound card damage is by far and away the most likely cause. But...

      I am only able to bring the recording onto the horizontal centre line
      by dropping the recording level to almost zero. When this happens there
      is virtually no sound in Adobe.




If, when the input level is reduced to zero, the flat line is at the centre of the screen and only shifts when you increase the level, it may well be the MD. The way to tell is to unplug the MD recorder and then increase the input level. If the line shifts without the MD being connected, then it's not implicated directly. But if it shifts as the level is increased with nothing connected, then your sound device has been damaged.