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 Post subject: Strange behavior from my YPVS servo
PostPosted: Sun May 13, 2018 3:25 am 
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Joined: Mon Dec 26, 2005 1:13 am
Posts: 334
Location: Melbourne Australia
I'm getting a strange rapid oscillation in the YPVS servo at the tail end of it's cycle when the ignition is turned on, If I twist the pulley home it ceases.
Does anyone know what is causing this?

Image20180512_125150 by Matthew Leahy, on Flickr

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 Post subject: Re: Strange behavior from my YPVS servo
PostPosted: Sun May 13, 2018 8:40 am 
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Joined: Fri Sep 02, 2011 7:02 pm
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Location: UK
Sounds like your pv cables do not have enough slack.


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 Post subject: Re: Strange behavior from my YPVS servo
PostPosted: Mon May 14, 2018 4:50 am 
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Joined: Mon Dec 26, 2005 1:13 am
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Thanks Begbie, I'll double check them.

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 Post subject: Re: Strange behavior from my YPVS servo
PostPosted: Mon May 14, 2018 7:14 am 
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Joined: Thu Mar 09, 2006 12:54 pm
Posts: 243
Location: Germany
Something got stuck and the jerking you see is the strategy to overcome it.
Check if the bowden cables pull out easily and if the valves rotate easily in their cylinder bores.
The latter one can be cured with using pliers to move them until it gets easier.

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 Post subject: Re: Strange behavior from my YPVS servo
PostPosted: Wed May 16, 2018 7:16 am 
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Joined: Tue Jul 19, 2011 7:49 pm
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Location: Toulouse France
Does it occur with cables removed ?


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 Post subject: Re: Strange behavior from my YPVS servo
PostPosted: Thu May 17, 2018 12:04 am 
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Joined: Wed Apr 20, 2011 3:18 am
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Location: Niagara, Ontario,Canada
Are the YPVS cables routed correctly between the rear pipes?

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 Post subject: Re: Strange behavior from my YPVS servo
PostPosted: Thu May 17, 2018 4:52 am 
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Joined: Mon Dec 26, 2005 1:13 am
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Thanks for the input folks, I'll check all this on the weekend.
I was initially thinking it might be a problem with the potentiometer in the servo or a problem with the controller but it makes more sense that it's a mechanical issue.

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 Post subject: Re: Strange behavior from my YPVS servo
PostPosted: Sat May 26, 2018 4:29 am 
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Joined: Mon Dec 26, 2005 1:13 am
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So, disconnected the cables at the servo, servo operates as it should, disconnected the cables at the bell crank, the cables are free and operate smoothly, rotated the power valves manually about a dozen times, sprayed some lube on the linkages re-assembled and re-adjusted the cables and now eveything works just fine.
Thanks for all the suggestions folks.

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