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LP12 Nima Problem

L

Lefty

Trade: Amar Sood Photo
Unfortunately I have encountered a problem with my recently acquired LP12. I went to play a record on it tonight (probably only the 6th or 7th time I've listened to it since I got it) and noticed the Nima has come loose from the armboard. (i.e. it rotates). I have linked a short video to show what I mean:


I tried tightening the arm pillar grub screw, but as the arm base is also rotating am I right in saying the problem is actually the bolt that screws to the base of the arm, under the arm board? (i.e. that has come loose).

If so, is there an easy way to tighten it without having to take everything apart and upset the suspension / need to set the turntable up again?

Lefty
 
It’s the nut that tightens the threaded pillar to the arm board, you’ll have to go in from underneath with an appropriate spanner/wrench.

Can’t see why you would have to reset the suspension, remove the platter and sub-platter, tape up the suspension if you think it moving will cause a problem, take off the bottom cover and do the deed, shouldn’t take long.
 
Easy fix. It's the same as older Rega arms. Take the base off the deck and tighten the big nut holding the arm on. Job done.
 
Thanks everyone for the quick response - I thought as much. (Of course I meant nut, not bolt!)

I'll lock the arm's bearing as well by putting it into its transit position.

Any tips on what I could use as a setup jig to allow me to keep the deck level while gaining access to the bottom from things lying around around house?

I'll give it a go tomorrow (remembering to also remove the platter / sub platter as well)

Lefty
 
Lefty said:
Any tips on what I could use as a setup jig
Click to expand...

Children? Significant other? Lego? Zoom lenses? ;)

Just tape up the suspension if it worries you, tip the deck backwards while you remove the bottom and tighten up the nut, don’t be too shy about tightening it up either, hand tight isn’t enough or you’ll be back in there in a couple of months. Hand tight and a 1/4 or 1/2 turn further than that.
 
Lefty said:
Thanks everyone for the quick response - I thought as much. (Of course I meant nut, not bolt!)

I'll lock the arm's bearing as well by putting it into its transit position.

Any tips on what I could use as a setup jig to allow me to keep the deck level while gaining access to the bottom from things lying around around house?

I'll give it a go tomorrow (remembering to also remove the platter / sub platter as well)

Lefty
Click to expand...
Don’t remove the sub platter, not necessary and you risk contaminating the bearing oil.
 
Lefty said:
Any tips on what I could use as a setup jig to allow me to keep the deck level while gaining access to the bottom from things lying around around house?
Click to expand...

For small simple jobs I used to work on it from underneath with the place I needed access to slid over the edge of the dining table. No need to flip it or turn it over then.

For just tightening the arm nut I'd be doing that.
 
What ever you do, do not hold onto any part of the tonearm, its bearing housing and/or arm rest platform whilst tightening from below. The best way to counter any rotating force is to insert a 1.5mm hex key into the height adjust grub screw and hold onto that such that it both counters the rotation of the threaded arm holder whilst tightening the nut down below, and allows the grub screw to be aligned rightward such that it remains accessible for adjustment of tonearm height.

This is covered within the Nima manual.
 
david ellwood said:
I’ve never heard of taping up the suspension?
Click to expand...

Just to stop it moving if you’re worried that perfectly ordinary springs moving in a way that they’re actually designed to move in, might somehow change the way they’re supposed to move in. It seems to be a Linn ocd type thing, and I have no idea how far down the Linn rabbit hole Amar is, so, if he’s worried about about it going weird, tape it up so it doesn’t move while he carries out a minor adjustment whilst the table is in a plane that it is not normally in.

Personally, I wouldn’t bother, but then it’s a long time since I’ve owned a fruit box, which I quite liked, btw, so I’m not sure if their springs are of lesser quality than in the 1980’s. I’m pretty sure they’re quite a bit more expensive in relative terms these days so one would hope they’re even more resilient...
 
Thanks so much for all the advice chaps. Where else can one get such a comprehensive guide on how to do something so niche at 11pm on a Friday night? I love PFM.

I feel confident enough to attempt it. I will use the hang it off the edge of a dining table method. I will keep the sub-platter in place but will raise it slightly by resting it on some books so the spindle is not in contact with the ball bearing. My main concern is protecting the arm bearing as it feels really delicate. I think the only way is to fully lock the bearing in its transit position.

I will report back. Wish me luck!

Lefty
 
The Nima bearing itself is just a stainless steel pointed grubscrew sitting in a counter-sink in the top of the stainless pillar
 
Thanks again chaps. The deed has been done and I'm pleased to say it went without a hitch. The only issue was I couldn't get a spanner in there due to the chassis getting in the way where it's screwed to the armboard. However, I was able to hand tighten it pretty well, largely thanks to @Craig B advice to use the arm grub screw along with allen key to give me sufficient leverage. This worked a treat. Whilst not as tight as it would be had I used a spanner, I'm hoping it's tight enough to stop it coming loose again. I did consider using a pair of pliers, but it seemed a bit barbaric and I was worried that if I lost my grip with them, the pliers could hit parts of the innards and cause further problems.

A play test confirms that it's sounding as good as ever. Looking forward to having a listening session tonight :)

Lefty
 
Lefty said:
Thanks again chaps. The deed has been done and I'm pleased to say it went without a hitch. The only issue was I couldn't get a spanner in there due to the chassis getting in the way where it's screwed to the armboard. However, I was able to hand tighten it pretty well, largely thanks to @Craig B advice to use the arm grub screw along with allen key to give me sufficient leverage. This worked a treat. Whilst not as tight as it would be had I used a spanner, I'm hoping it's tight enough to stop it coming loose again. I did consider using a pair of pliers, but it seemed a bit barbaric and I was worried that if I lost my grip with them, the pliers could hit parts of the innards and cause further problems.

A play test confirms that it's sounding as good as ever. Looking forward to having a listening session tonight :)

Lefty
Click to expand...

Top tip for hand tightening nuts is to wrap an elastic band around it or on to your fingers as you get far more purchase, hope it's sorted anyhow!
 
@matt j - thank you, I'll keep that in mind for future reference!

Vinny said:
The Nima bearing itself is just a stainless steel pointed grubscrew sitting in a counter-sink in the top of the stainless pillar
Click to expand...

Indeed - my worry is that the grubscrew could scratch / mark the counter-sink, thus creating friction / notches which will inhibit smooth functioning of the uni-pivot? I even make sure to gently pull the spike out of the bearing whenever I am making counterweight adjustments, just to be on the safe side. (perhaps I am being too cautious?)

Lefty
 
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