Spring fell out? That doesn't seem right...

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dougc84
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Spring fell out? That doesn't seem right...

Post by dougc84 »

I've got a 2007 Fly Mojo Flame. Love this thing so much. Aside from replacing one of the switches, I've never even opened the back up or touched the trem system - until tonight.

I was playing, pulled up on the bar slightly, and... OH SHIT, did I break it? All the strings went flat, the bridge was in a weird place, and I could hear metal jangling around.

I popped the back off and my spring had completely fallen out. I inspected everything and it all looked fine. I put the spring back in place and everything was super flat. I tuned up and everything seems okay, but the bridge looks like it's sitting a little more proud off the body than normal.

However, I'm wondering if I'm missing something. In 17 years with this guitar, I've never had the spring fall out when pulling up on the trem arm. But I found that I can repeat this behavior if I pull up on it again without fail. Is there not some sort of clamp on the spring to keep it in place? Or is this expected behavior for this guitar and, somehow, it has just never happened until now?

And, in pulling it out, I accidentally dropped the cover and yanked one of the 9V compartment cables off. Ugh. What a day. Where's that soldering iron?
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mmmguitar
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Re: Spring fell out? That doesn't seem right...

Post by mmmguitar »

@dougc84, I'm curious about approximately how many steps up in pitch your G detunes before this happens. Though it's likely different for every Fly, I just measured my 2011 (same parts as your Mojo) as having around 3.31mm/0.13" space for pull-up travel between the ridge plate and step-stop block's points of contact.

step stop gap.JPG

Because the orientation of the Fly spring being anchored behind the bridge means that pulling up decompresses it via pulling the ridge plate away from the stationary T block the other end of the spring is set into, the step-stop block's job is to set the maximum pull-up travel for the ridge plate in order to prevent what you're describing from happening - But it only works if the following two conditions are met:

1. That the zero position of the trem is calibrated via the step-stop being able to swivel in and out of the block position without affecting string pitch (with the trem barely being able to pull up in the dive-only step-stop position), and

2. that the spring is under sufficient compression to counterbalance the string tension at zero position that it does not fully decompress at the max point of pull-up travel dictated by the step-stop block's distance from the ridge plate in floating mode.

Have you been using the same spring for seventeen years, and do you have a spare to A/B with? This other member's spring issue would likely produce the same symptom you're experiencing. In their case, it's caused by the spring being too stiff to compress under the pressure exerted by their string set tuned to pitch. I mention it because the springs themselves are a factor difficult to diagnose or rule out without having a spare to swap in.
Summary of the Parker Guitars speculator market from 2020 onward: https://en.wikipedia.org/wiki/Greater_fool_theory
dougc84
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Re: Spring fell out? That doesn't seem right...

Post by dougc84 »

Hey @mmmguitar - It's not when I drop the bar and go flat, it's when I pull up on it and go sharp.

I generally have it set in floating (not fixed/drop only) mode. I can move back and forth without issue (there is no change in pitch). Detuning works fine all the way down until the bar hits the body of the guitar, and I can watch the spring bend nicely. Pulling up (going sharp) eventually releases the spring from the clamps entirely.

It does seem like there is very little tension applied to the spring when in unity. It doesn't take much to pull up and drop the spring. It also seems really finicky (I've never worked on the trem system myself), like, I'm not sure how it all holds together in the first place. The T bar at the butt of the guitar just kinda sits in a hole and can easily fall out, and the bar toward the neck with the three slots - I'm not sure the reasoning for the multiple slots. However, I feel like, if there was added tension on the spring, you'd never be able to get the spring in or pull one out.

I'm considering picking up another spring. To be honest, I'm not a huge trem user, but I guess, even without excessive use, it's still had 17 or so years of tension on it.
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vjmanzo
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Spring fell out? That doesn't seem right...

Post by vjmanzo »

Hi @dougc84—do you generally tune the instrument in fully-floating mode? Meaning, is the step-step ever down? There’s nothing “wrong” with that, but if so, it might explain some of what’s happening.

It’s a balancing act, as you know, getting the vibrato bridge to float properly; specifically, it’s a balancing act between the strings pulling the back of the bridge toward the headstock and the spring pushing the bridge back so that its vertical. As the threaded rod in the body moves in and out of the recessed cavity, more or less tension will be applied to the spring, which you can counteract by tuning—this is the balancing act. The reason to balance the bridge so that it uses the step-step as a means of switching between full-floating mode and bend-down only mode is that you’d then have tuning consistency while switching between both modes; you’d get some of the pitch-stability benefits of a hardtail when in bend down only, which can be useful for string bends and have an easier time tuning the instrument than when it’s floating.

When players set up their Fly to use the step-stop in this manner, then they’d be likely to see between 10 and 15 threads showing on that rod once it’s balanced and in tune. However, if you’ve only been tuning the guitar while it’s floating, you can actually achieve that balance of the bridge at various points regardless how many threads are showing on that rod—you just tune the strings to pitch and the spring pushes back on the bridge wherever it is relative to the threaded rod.

This wouldn’t be an issue except that there is a point where the threaded rod may be so far into the recessed cavity that bending up causes the spring to fall out from between the three-ridge spring plate and the t-bar like you’re describing, but this sentence—as an explanation for what you’re experiencing—is a guess. I’ve never heard of that happening while someone was playing. If you’re swapping a spring, you really have to back up that threaded rod a lot and then bend the bridge up to to get the spring to drop out—I always have the guitar detuned while I’m doing that.

If this were me, I’d detune the guitar until the strings were flopping, then move the threaded rod so that about a dozen threads are showing, and then start to bring the guitar back into tune with the step-stop down using the steps described in this post. I would love to hear that this fixes the strange issue you’re having.

Again, that’s what I’d try before I went looking to swap the spring. Usually when the springs fail, you get the opposite problem—the spring is no longer putting enough tension on the bridge, so you have to really crank the threaded rod out (more than 15 threads showing) so that the bridge doesn’t tilt forward.

I hope this helps!!

#VibratoBridge
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