From: legg@nospam.magma.ca   
      
   On Mon, 12 Feb 2024 15:58:16 -0800 (PST), Samuel Oh    
   wrote:   
      
   >On Sunday, January 15, 2023 at 6:07:33?PM UTC-8, Joe Jaramillo wrote:   
   >> On Sunday, September 25, 2022 at 11:23:12 AM UTC-7, Joe Jaramillo wrote:   
   >> > I have the same problem on a C 430. I’ll be playing either quiet or loud   
   and then a hear A rumbling noise that kind of trails off for a bit and then   
   comes back. Did you ever find out what the root cause was?   
   >> > On Wednesday, March 12, 2003 at 9:56:01 AM UTC-8, Michael and Janet Inman   
   wrote:   
   >> > > I have a Yamaha CLP-411 Clavinova that is about five years old. It has   
   >> > > developed an occasional rumbling sound that comes from both speakers.   
   >> > > It only lasts a few seconds at a time, is unbelievable loud, very low in   
   >> > > pitch, and sounds just like wind noise on a microphone. Seems to happen   
   at   
   >> > > random times although more common when someone is playing it. Volume   
   >> > > control position has no effect on the noise volume but does sometimes   
   seem   
   >> > > to affect the timbre of the noise. It goes away when you plug   
   headphones in   
   >> > > (you don't hear it in the headphones).   
   >> > > Without the benefit of a service manual/schematic, I have tried to   
   trace the   
   >> > > analog audio signal with an oscilloscope to at least determine from   
   which   
   >> > > stage the noise is coming. I'm suspecting it's originating in the power   
   amp   
   >> > > section - the amps are IC "bricks", one for each channel but since it's   
   in   
   >> > > both speakers equally I'm thinking it's not them. Due to the sheer   
   volume   
   >> > > of the noise it actually loads the power supply to a point where   
   signals at   
   >> > > all stages are affected. I did change the filter cap in the dc supply.   
   No   
   >> > > improvement.   
   >> > > I did read some newsgroup accounts of noise in the Clavinovas being due   
   to   
   >> > > dirty contacts in the volume control... I'm picking up some contact   
   cleaner   
   >> > > today and will try that but I'm not too optimistic about it.   
   >> > > Any experience with this problem or guidance much appreciated.   
   >> > > Mike   
   >> Incidentally it also happens with headphones so I’m a bit flummoxed. Oh and   
   btw I have a CLP-440. Next stop Yamaha…   
   >Oh damn my church piano developed this issue too a few months ago, and it's   
   been driving me crazy!   
      
   Check for degraded adhesive used on pcb assys for vibration   
   defense.   
      
   Remove it and clean the area with alcohol, anywhere it comes   
   into contact with board traces or connector terminals.   
      
   RL   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)