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C pedal problem

Posted: 28 Apr 2019 7:10 am
by Rani Platek
An old problem I’m trying to solve again:

On my Mci s10 (Emmons setup) the C pedal raises strings 4 and 5 a whole tone. Problem is that I can never get a full tone raise on the fourth string, E to F#, always short in about ten cents (I tune my E’s 3 cent sharp, but still i need 7-8 cents to reach the desired F#).

What is noticed is when I reach a certain point in the pedal travel, the lowering finger spring start to streach.. an obvious fault.. so I tried to shorten the spring to make it stronger but it didn’t help, also I’ve tried different springs (and in the past different string gaughs). Do you guys think it’s in the spring only, and I should maybe shorten it more, or there are more issues that can cause this problem..?

Thanks!

Posted: 28 Apr 2019 7:35 am
by Bill Moore
Just a thought; you should be using a .014 for the 4th string. Using a heavier string might cause your problem.

Posted: 28 Apr 2019 10:24 am
by Rani Platek
Yes I’m using 14

Posted: 28 Apr 2019 11:47 am
by Ian Worley
Tightening the spring more is the obvious solution, springs weaken over time, but there could be other mechanical issues at play too, scissor binding, etc. If you over-tighten the spring it will affect the feel and operation of the lower and may not really correct the underlying problem.

Before you shorten the spring further, you could do a test by simply wiring the scissor in place temporarily so that it can't move, overriding the spring. You can then see if this corrects the raise issue or perhaps illuminates a secondary problem. The lower scissor should never lift off the stop during a raise, if there is something else binding that is causing the issue this should help you figure out what it is

Posted: 28 Apr 2019 12:37 pm
by Craig A Davidson
Is this a new issue since a string change or has the guitar always been this way?

Posted: 28 Apr 2019 12:42 pm
by Jerry Overstreet
...sounds like a problem of not enough travel. Loosen the pedal stop so that it can pull the string further. After this, string 5 will be sharp with the pedal pull, so you'll need to re-tune it.

Posted: 28 Apr 2019 1:03 pm
by Ian Worley
Jerry Overstreet wrote:...sounds like a problem of not enough travel...
Lengthening the travel will just allow it to pull the lowering scissor further off the stop. When a raise is pulling the lower scissor off the stop it is a self-defeating operation no matter how much travel the pull has

Posted: 28 Apr 2019 1:34 pm
by Ken Metcalf
Does 10 cents short sound in tune?

Posted: 29 Apr 2019 3:19 am
by Rani Platek
Craig A Davidson wrote:Is this a new issue since a string change or has the guitar always been this way?
Yes, always been this way.

Posted: 29 Apr 2019 3:47 am
by Rani Platek
Ian Worley wrote:Tightening the spring more is the obvious solution, springs weaken over time, but there could be other mechanical issues at play too, scissor binding, etc. If you over-tighten the spring it will affect the feel and operation of the lower and may not really correct the underlying problem.

Before you shorten the spring further, you could do a test by simply wiring the scissor in place temporarily so that it can't move, overriding the spring. You can then see if this corrects the raise issue or perhaps illuminates a secondary problem. The lower scissor should never lift off the stop during a raise, if there is something else binding that is causing the issue this should help you figure out what it is
At least one time when I tried replacing he spring with a hard wire it helped to fix the problem.

Posted: 29 Apr 2019 10:40 am
by Jerry Roller
Rani, try backing the 4th string tuning nut completely off and retune it. It may be pulling too far due to overtuning. If it is the gray MCI I sold you it was not doing that when it was shipped. A lot can can happen in three or four years. I would first slowly press the C pedal and see if it pulls to pitch then starts going flat. Overtuning will cause it to drag the lowering finger. Also check very carefully to see if a broken string end might be hung in the changer. Email me at rollermusic@cox.net and I will help you correct it. (For sure!)
Jerry

Posted: 30 Apr 2019 4:31 am
by Rani Platek
Thanks Jerry and everybody
All you have mentioned have been tested already. Few years agowhem I got the guitar it was Day setup, I’ve changed it to Emmons setup, maybe I didn’t arrange stuff well enough, there was other changes I did in the Copedent as well.

Posted: 30 Apr 2019 7:34 am
by Jerry Roller
Email me Rani, we can fix it.
Jerry