[HAM] Motor boating noise has returned to my friend's 1959 C3 even though the vibrato scanner was cleaned and reassembled twice.

[David Anderson]

Keith,

Just out of curiosity, what's the principle behind the alcohol soak procedure? I did this with the scanner on my recent organ project just to get the parts nice and clean before reassembly. 

Also, I have heard from some very authoritative techs that oil has little or nothing to do with motorboating vibrato. They've seen oil-soaked scanners that sound fine, and it makes sense. Oil is a good insulator; otherwise, there would be no paper in oil capacitors. I suppose oil can catch metallic dust.

I wonder if the preamp in Kon's friend's organ has a leaky 1uF capacitor at the output to the vibrato line. I'd have him check to see if there is any DC voltage on the vibrato line. In that case, the vibrato line would be acting like a voltage divider with the scanner is picking up a varying charge with every rotation. It would be an easier place to start than another complete scanner breakdown.

David

-----Original Message-----
>From: Keith H Clark <organtec at charter.net>
>Sent: Feb 25, 2008 5:57 AM
>To: 'The Hammond Forum' <hammond at zeni.net>
>Subject: Re: [HAM] Motor boating noise has returned to my friend's 1959 C3	even	though the vibrato scanner was cleaned and reassembled twice.
>
>Kon,
>   Take the scanner out again. Dis-assemble everything again. Soak the
>washers in denatured alcohol, 2 bowls. Soak in first bowl,dry,resoak in new
>clean bowl and dry. Do this to all screws etc and stator plates.Reassemble.
>Will be good for 10+ years anyway.