AMI J120 tonearm tracking force

[halfwaytree]

My J120 has a Shure M44 cartridge with a N44C stylus which has a max tracking force of 5g. Currently the best I can get is 8g using the copper spring under the tonearm. If I go any lighter than this then the tonearm is either held too high and doesn't descend onto the record or at best tends to skip or skate particularly at the run out grooves and then doesn't trigger the shutoff switch. The tonearm wiring has been replaced with a very lightweight thin wire that is dressed to provide minmum drag. The shutoff switch lever creates a little drag but I can move it so it is out of the equation but the tonearm still skips at anything lighter than 8g. Has anyone been able to get a lower tracking force than this? As far as I can know the original Sonotone ceramic cartridge also tracked at about 5g.

My Rocko-Ola 454 tracks with no problem at 4g using the same cartridge and stylus.

[jukeboxmarty]

The J120 manual I have states that the tracking force should be between 8 and 12 grams. This sounds correct for the GE cartridge commonly supplied with these machines.

If trying to reduce the factory tracking force, I would make sure the tone arm is well lubricated, especially in the area of the 'tone arm rest' pivot. If I recall there should be a ball bearing present which commonly falls out when the tone arm is lifted out of position.

[halfwaytree]

Thanks for the suggestions. I can't see a ball bearing on the tonearm components diagram I have or on the components list. However, looking at the tonearm components diagram again I see that the tonearm return spring is missing, so I'll try and get one of those and see if that makes a difference.

[jukeboxmarty]

On further investigation it looks like the tone arm ball bearing started with the 'K' model. My memory was only off a bit!

www.jukebox-world.de/en/Jukebox-Parts-USA-oxid/AMI-Rowe-AMI/AMI-K/Tone-arm-bearing-assembly.html