F lever tuning drifts

Mats Raknerud · From: Norway

Hi. On my Zum e9 I allways have to flatten the the E-F lever when I start to play, and from there it slowly drifts back to where it was during the first 30 minutes of playing.
The other changes are pretty much bang on except if I just got the guitar in from a cold car or so.
But having to constantly chase the F-lever tuning bugs me. We’re not talking an awful lot. But maybe something like 7-10 cents.

Does anyone have an idea what’s causing this?

Have a great day!

Mats. Smile

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Strings don't drift up! Sounds like it's over-tuned. To test this, pick the 4th string, and then (without activating the lever) loosen the 4th string raise tuning nut a quarter turn, and see if the 4th string tuning drifts lower. If it doesn't, then do the same with the 8th string. If loosening either tuning nut makes the 4th or 8th string go lower, you have no slack and you must back off on the tuning nuts completely and start over retuning the pulls.

Lee Baucum · From: McAllen, Texas (Extreme South) The Final Frontier

Jon Light wrote this most excellent piece on overtuning.

It's a "sticky" at the top of the Pedal Steel page.

https://bb.steelguitarforum.com/viewtopic.php?t=326460
_________________
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There are only two options as I see it.
Either I'm right, or there is a sinister conspiracy to conceal the fact that I'm right.

Williams Keyless S-10, BMI S-10, Evans FET-500LV, Fender Steel King, 2 Roland Cube 80XL's,
Sarno FreeLoader, Goodrich Passive Volume Pedals, Vintage ACE Pack-A-Seat

Jon Light · From: Saugerties, NY

I have seen levers be inconsistent. Not 'drifting' but raising erratically, sometimes raising (or lowering) X amount, and other times Y amount.
There are several potential causes of this.
Among them, lateral movement on the lever's mount or cross shaft causing the lever to hit its stop in different places on the stop screw as it moves laterally.
Also, a loose bellcrank can be erratic.
Also, pull trains might be binding due to humidity shifts of the body and/or need for lubrication, making the string movement from the pedals and levers more sensitive to how fast and hard they are engaged.

Bottom line? A picture of what you have, and definitely identifying exactly what guitar it is will make this less of a guessing game and more of an informed assist. Is this a full-pro Zum or a Stage One or an Encore?

And thank you Lee -- yes, overtuning is always something that needs to be examined.

Mats Raknerud · From: Norway

Thank you for answering.

It’s a pro version zum from 84 i believe.

Been serviced by a proffesional a couple of times the last three years also. So it’s in top shape except for this issue.

It’s not a case of overtuning.

And the weird thing is that once it settles in after about 30 - 60 minutes of playing the e-f change is stable. But up to that point it’s too sharp. I have tried to not tune the nylon nut, and every time it ends up being perfectly in tune after a while. But this can be a pain on stage. Tuning the e-f change between the first songs.
And it’s only on string 4. String 8 behaves as it should.

I’ll se if I can get a video of the problem tomorrow. Smile

Ian Worley · From: Sacramento, CA

Tucker Jackson · From: Portland, Oregon, USA

I think Ian is on the right track when he says that, as part of the raise action, the lowering-scissor for the 4th string is moving when it should not be. That will always cause tuning problems.

In addition to a weak spring, the problem might be caused by stickiness where the two scissor pieces are connected together with a rivet, deep down in the changer. This gummy stickiness goes away as you play the guitar. Friction warms the parts and they begin to move more freely on that rivet, as they should.

If you tune the F-lever when the changer is cold and scissors are sticking, when they un-stick after you play for a while, the pitch will rise. You are getting a pure raise at that point, with no (incorrect) lowering added in.

You can test this theory with the guitar in the case when it is cold by moving the F-lever by hand. Watch the changer. In a perfect world, the end of the lowering-scissor for the 4th string should not pull away from the stop-bar. The easiest thing to look for is movement of the spring: it should not move when you are doing a raise. If the spring does move, then the lowering-scissor is moving from its "at rest" home position when it should not be.

As Ian said, one solution is to tighten that spring. But if the problem is not that the spring is weak, if it is really sticky scissors, tightening the spring will maybe overcome the problem but not really fix the root cause. So you can try to put one drop of lube on the rivet that holds the two scissor pieces together. Since this is deep down in the changer mechanism, you can use a long spout or a piece of wire to run just one drop of lube to deliver it to the rivet. You may have to remove the spring for the 4th string to get access to that rivet.

See this web page. The rivet is the small dot in the middle of the diagram. This labels them as 'raise finger' and 'lower finger' instead of 'lowering-scissor' but it's the same thing.

http://steelguitar.com/maps/changer.html#
.

Mats Raknerud · From: Norway

I’ve tried to film the problem. Smile

https://youtu.be/6JxVkjdw5Zw

And here's a picture after I oiled it. A good amount of dirt on the e-string changer. Maybe I should take it apart and do a cleaning job?

Jon Light · From: Saugerties, NY

I see you have raise helper springs. I suggest disconnecting them (as part of your diagnostic procedure).
No -- the lower return springs should not be moving at all on the raises. Ultimately, lubrication or even, first, solvent degunking is what I suspect is called for.

Mats Raknerud · From: Norway

Raise helper springs, is that what I call "return compensators"? It's on all the strings that both lower and raise. If I untighten the screws that is attached to the return compensator my strings won't return properly after lowering. So they work as they should. But yes, I can see that the tuning is more stable on the strings that don't both lower and raise.
I'll try to loosen the screws on the picture and se if the e-f raise is more stable.

Jon Light · From: Saugerties, NY

No no -- this is the raise helper spring I'm talking about:

Mats Raknerud · From: Norway

Ok. But Can you tell me what the screws I pointed out do? I Thought they where for the compensators. And now that I have loosened the one for the high e it behaves just like it would without a return compensator. Returning a little sharp after being lowered.

What does a raise helper spring do? Should I loosen it completely?

I can see three sets of springs:
- return springs (the ones closest to the floor)
- a set of springs on just some of the strings (in the middle)
- a row of smaller springs all across the strings (farthest from the floor)

The smaller springs seems almost impossible to get to if I don't dissemble the whole thing. Smile

Jon Light · From: Saugerties, NY

The raise helpers simply make the pedals lighter, easier. They are 100% expendable. You can remove them or, if they are adjustable, reduce their tension with no side issues. I am NOT at all certain they are the issue. But mis-adjusted raise helpers can cause problems or, in the event of other issues, they can exacerbate problems.
I am not familiar with Zums so I will not try to answer your question about those screws. I have never seen split tuners or return compensators in that location so I'm not sure what I am looking at. I'll leave that to someone who actually knows.

Mats Raknerud · From: Norway

Ahaaa!
That's great to know. Thank you so much for answering.

Ian Worley · From: Sacramento, CA

At about 1:08 in the video you pointed at the lower return springs and commented "these should not be moving". That is correct, the lowering scissors needs to remain in firm contact with the stop bar. The springs should be tightened, but they appear to be at the end of their range so you will likely need to remove the springs and trim off a couple of coils, then reset the nut inserts a little deeper into the spring to give some more adjustment length. To reset the insert you can relax the spring by rotating it in the opposite direction to allow screwing the insert in a bit farther.

This may or may not be the source of your problem, but it is likely at least contributing to it. You should check and make this adjustment for any other springs that don't hold the lowering scissor tight against the stop bar when a raise is activated. You don't want to over-tighten them either as this will make the lowers stiff and can cause other issues. Make them just tight enough to hold the lowering scissor firm on the longest raise for each string.

Raise helper springs can sometimes cause similar issues on lowers, but not raises, they're working in the opposite direction. They are generally not a great idea IMO on strings that have both a lower and a raise, but they're not likely contributing to your specific problem here.
_________________
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Jon Light · From: Saugerties, NY

Mats Raknerud · From: Norway

https://youtu.be/n1mrlDaD9KU

Wow!! My english is a lot worse than I thought. Hahaha!
Well, hopefully you can both understand what I’m trying to say and get a good laugh as well.

Jon Light · From: Saugerties, NY

A) language is not an issue at all
B) the only return compensators with which I am familiar address lowers returning sharp. They would not be a factor with the raise mechanics.
C) again, I won't muddy the waters by speculating on those screws.
D) It does appear that shorter/tighter springs are called for. But that could very possibly be because of gunk in the changer affecting the free movement of the raise & lower fingers. The most correct hing you could do is to clean the changer (flushing it with something like naphtha without removing the changer, definitely an outdoor activity, or removing the changer and dunking it in a bucket of solvent). I could see this eliminating the need for messing with the springs.

Ian Worley · From: Sacramento, CA

I've never seen return compensators done like that but I think you may be correct about the row of screws. I thought at first it was a hybrid changer, they have a row of screws like that to adjust the open note, but it's on the raise side, not the lower.

Jon's suggestion for cleaning is a good idea, gunk is always a likely culprit.

Also, you should be able the shorten the springs from the hook end, just bend it down a couple of loops in to make a new loop and clip off the excess. Good luck!
_________________
All lies and jest, still a man hears what he wants to hear and disregards the rest - Paul Simon

Mats Raknerud · From: Norway

I’ll try to clean it.

Naphta, that’s the stuff you would use to clean paint brushes with, right?

Mats Raknerud · From: Norway

So I tried to take out the changer and clean it. But I just can't get it out. When I wiggle it, I can se that the hardware outside the rod that goes through changer goes under the fretboard and can't be moved. The pickup seems to be mounted in the same piece of metal that goes outside on each side of the changer. So I just wonder if I have to take off the whole fretboard to unmount the changer. Seems like a fair bit of work since the screws that mounts the fretboard to the body collide with the stop points for the pedals and such.

Anyone who knows? Smile

I also uploaded some better pictures of the smaller springs. What do these do?

Jon Light · From: Saugerties, NY

I would instantly say that the springs with the white nylon beaded pullers are the raise-helpers. This is the method used on my Williams. However because I do NOT know what the row of ten springs closest to the deck are, I am hesitant about everything.
My casual speculation is that the ten springs are actually across-the-board raise helper springs as part of the balancing act of a Zum pull train and that the others with the nylon are additional adjustable helpers. I hope to learn, as someone explains (I'd love for Bruce to drop in).

Can't help on the changer removal. My respects to you for diving in.

Danny Letz · From: Old Glory,Texas, USA 79540

The row of ten smaller springs against the body hold the spacers between the changer fingers against the body. This is a sound transfer or “body contact” device. Removing or altering these springs have NOTHING to do with the adjustment of the guitar. The next row of larger springs are raise helpers & probably not on every changer finger. The row of screws below the nylon tuning nuts are an early form of return compensator. This appears to be a Zum from around the 1984ish era & they usually sound very good.

Danny Letz · From: Old Glory,Texas, USA 79540

Just a little farther explanation. The spacers between the finger elements on the changer axle that might just be spacer washers on some other guitar is instead elongated into a blade that extends beneath the guitar. There it is firmly held against the wood cabinet by the small springs. Again, this for sound transfer & has nothing to do with any adjustment on the guitar.
On the return compensators there is a tiny compression spring in the bore of the adjusting screw that bumps against the changer finger. I guess it works like the o rings on the later ones to cushion the return of the finger.

Donny Hinson · From: Glen Burnie, Md. U.S.A.

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