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Strange behavior from my YPVS servo

Posted: Sun May 13, 2018 3:25 am
by Matty
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

Re: Strange behavior from my YPVS servo

Posted: Sun May 13, 2018 8:40 am
by begbie
Sounds like your pv cables do not have enough slack.

Re: Strange behavior from my YPVS servo

Posted: Mon May 14, 2018 4:50 am
by Matty
Thanks Begbie, I'll double check them.

Re: Strange behavior from my YPVS servo

Posted: Mon May 14, 2018 7:14 am
by MK
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.

Re: Strange behavior from my YPVS servo

Posted: Wed May 16, 2018 7:16 am
by phildu31
Does it occur with cables removed ?

Re: Strange behavior from my YPVS servo

Posted: Thu May 17, 2018 12:04 am
by 2smoke
Are the YPVS cables routed correctly between the rear pipes?

Re: Strange behavior from my YPVS servo

Posted: Thu May 17, 2018 4:52 am
by Matty
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.

Re: Strange behavior from my YPVS servo

Posted: Sat May 26, 2018 4:29 am
by Matty
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.