Forum Top Banner Ad


Ebay Classic organs



No announcement yet.

Aurora Classic, mains hum and Leslie noise

  • Filter
  • Time
  • Show
Clear All
new posts

  • Aurora Classic, mains hum and Leslie noise

    I'm wondering if relatively loud mains-frequency related hum is typical for an Aurora Classic. I've just replaced the three main filters capacitors 4000mfd, 50V, with no improvement to the hum. Also checked the rectifier diodes, all ok.

    While on the subject of noises, the Leslie mechanism in my Aurora makes a mechanical noise once per rotation when at full speed, but is perfectly quiet at Chorale speed. I've had it out of the organ, there is nothing obviously scraping. Again, am wondering if this is this typical.

    Would appreciate any feedback from other Aurora owners.


  • #2
    Can advise that in this instance the hum was due to poor connections at the pcb edge connectors to both power amplifier modules. After putting a fresh (thin) layer of solder on the pcb connector fingers, and cleaning the loom side connectors with a fine wire brush, the hum is much reduced.


    • #3
      Hi Gary

      Normal issue with the edge connectors, you'll probably do a few more over time. Routine maintenance for LSI models, but the later ones like yours are better than the first generation models.

      As for the leslie, if it's not scraping, it may be a bit out of balance or it may be just old age! Checking alignment of motors and drum? Sounds like you've done that!
      It's not what you play. It's not how you play. It's the fact that you're playing that counts.

      New website now live -

      Current instruments: Roland Atelier AT900 Platinum Edition, Yamaha Genos, Yamaha PSR-S970, Kawai K1m
      Retired Organs: Lots! Kawai SR6 x 2, Hammond L122, T402, T500 x 2, X5. Conn Martinique and 652. Gulbransen 2102 Pacemaker. Kimball Temptation.
      Retired Leslies, 147, 145 x 2, 760 x 2, 710, 415 x 2.
      Retired synths: Korg 700, Roland SH1000, Jen Superstringer, Kawai S100F, Kawai S100P, Kawai K1


      • #4
        Check to see if the black rubber grommets have pulled away from the foam Leslie rotor hub. If so push them back in and secure with some silicone glue.
        Servicing electronic organs since 1969.


        • #5
          Thank you td, that was exactly the problem. After repair, the Leslie is now much quieter. Thanks also to andyg for your advice.


          • #6
            I Have the same problem on a Aurora I just bought. Shouldn't I hear some "scratch" when I pull on the connectors if they are faualty?
            I have one key on the lower keybord that does not work - any tips on how to get access? and maybe what can be wrong?

            Regards Peter and thank's for a great forum.