Re: Digest for gale-audio@googlegroups.com - 3 updates in 1 topic

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Simon Yearwood

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Sep 21, 2020, 2:45:29 AM9/21/20
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On Mon, 21 Sep 2020 at 01:00, <gale-...@googlegroups.com> wrote:





Incredible ! Well done. 

















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Google Groups



















































al <alki...@gmail.com>: Sep 20 03:55PM -0700







Well, it turns out that an oscilloscope is an extremely useful tool for the


controller. With Howie's schematics you can trace what bit is non


functional: in my case the variable frequency generator on board 3. I


replaced the IC but that didn't work. So checked the power in and the -10v


rail was off. It comes through a resistor, which had failed. Replacing that


made everything work!


 


I also thought everyone might be interested in seeing the wow and flutter


trace and the corresponding voltage fluctuation in the drive to the motor,


which is surprisingly big (given that 33.3 is coded by 1.2v and 45 by 1.5v:


the variation is up to 0.1v!). The optical feedback loop is working hard


and I think the motor would be pretty ropey without it... The flutter is


typical of a direct drive: what is interesting is the biggest variation x1


per revolution, seen in both the wow/flutter graph and the voltage trace.


Can't make it go away however much I clean the disc: must be something


mechanical. Figures still excellent though...


 


On Monday, 24 August 2020 20:48:22 UTC+1, al wrote:










al <alki...@gmail.com>: Sep 20 03:56PM -0700







Well, it turns out that an oscilloscope is an extremely useful tool for the


controller. With Howie's schematics you can trace what bit is non


functional: in my case the variable frequency generator on board 3. I


replaced the IC but that didn't work. So checked the power in and the -10v


rail was off. It comes through a resistor, which had failed. Replacing that


made everything work!


 


I also thought everyone might be interested in seeing the wow and flutter


trace and the corresponding voltage fluctuation in the drive to the motor,


which is surprisingly big (given that 33.3 is coded by 1.2v and 45 by 1.5v:


the variation is up to 0.3v!). The optical feedback loop is working hard


and I think the motor would be pretty ropey without it... The flutter is


typical of a direct drive: what is interesting is the biggest variation x1


per revolution, seen in both the wow/flutter graph and the voltage trace.


Can't make it go away however much I clean the disc: must be something


mechanical. Figures still excellent though...


 


On Monday, 24 August 2020 20:48:22 UTC+1, al wrote:










al <alki...@gmail.com>: Sep 20 04:15PM -0700







.... and I just realised: the schematics are from Markus, not Howie. They


are what got me out of the hole. Thanks Markus!


 


On Monday, 24 August 2020 at 20:48:22 UTC+1 al wrote:


 
































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Markus Alber

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Sep 21, 2020, 5:07:32 AM9/21/20
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Hi Al end all the GALE-enthusiasts, thanks for the interesting measurements. Glad my schematics were of some help, sorry for my awful scribbling and possible mistakes, as always I was in a hurry, still intend to redraw them in eagle, but unfortunately no time so far….. 
All the best  Markus

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Jack Ward

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Oct 17, 2020, 10:39:14 AM10/17/20
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John Mayberry

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Oct 17, 2020, 5:38:01 PM10/17/20
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