Hi Tony,
In answer to your questions.
All 3 springs are the same length when lined up on the bench. However, the one in consistent use on the lightest (farest stretched) notch on the arm tracks at 7g. The other 2 weigh around 2g on the same notch. So the additional 30 years of being stretched has caused this as when I first had the jukebox it was 3g on a mid setting notch.
Needles. I have tried the same needles in my Continental and there is no issue there, the cantilever does not pull the cartridge along. Continental is tracking 3g on its bendy metal adjuster. That to me rules out styli.
The friction is uniform all along the arc. No binding at certain places. Even with arms and mounting post off the jukebox and in my hand the rotation of all 3 arms in their respective shafts feels stiffer than expected.
Regards
Nigel
On 22 Jan 2023 at 01:49, Tony Miklos via Jukebox-list jukebox-list@lists.netlojix.com wrote:
I can't help with all your questions, except I've never seen a spring go weak unless it was stretched to far. You do realize that the Tighter you make the spring, the Lower the tone arm pressure, right? So a stretched spring will make it a lot heavier.
I know you said you tried different needles, just throwing it out there that long ago I had some needles with so little compliance that with a loud bass note, the needle would actually jump out of the groove. (that's with the volume down low/not vibration from the speakers).
For troubleshooting purposes, I've often hung the end of the tone arm with a light string/thread and move the string right and left to see for sure which way (if only one way) and where the interference is if it's not in it's entire path.
Tony
On 1/21/2023 1:06 PM, Nigel Pugh via Jukebox-list wrote:
Can anyone tell me please is there a bearing in the bottom of the brass tone arm pivot ? I cant tell with a torch if it's actually a bearing or an indent ?
The reason I ask is, I have 3 of these arms and each one seems to have the same problem, there is too much horizontal friction in that bearing and the stylus cantilever is pulling the arm, so when you watch it close up it looks like the cantilever is doing a little dance to the let and right.
I'm experienced in tonearm setup and have ruled out everything other than friction in that shaft.
Pivot shaft flushed clean with IPA and lighter fuel, spotless
Tonearm cable removed completely
Trip switch removed
Tracking set with digital guage between 2 and 7 grams (Shure M44MR original cartridge)
This issue usually occurs when attempting to track a cartridge at the lighter end of it's spec, or with stiff tonearm cable
If I track at 7 grams it's ok, but that's definitely not right. Should be 3 to 5.
Tried with kiddie spring and also counterbalance
Used various new and used styli, M44C and domestic M44-7
I've got 7 jukeboxes and 8 turntables and by a long shot this arm has infinitely more friction than all of them. And all 3 variants of this arm do also, hence asking if there is or should be a bearing in the pivot.
Or, is it just a really bad design ?
Any ideas ?
I've had this 470 for around 30 years and only discovered this when I realised the crappy arm spring had stretched over time and was tracking on the lightest setting at 7g. So I made a counterbalance and that's how it's come to light that the arm don't like tracking below 7g. It also sounds much better at 7g. Something isn't right so I'm looking for an outside of the box thought or a sensible modification. Maybe there's nothing wrong at all and it's just a rubbish design. I did think about dropping a bearing into the shaft but haven't got one to hand.
Nigel, uk
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