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Help! Belt coming off at 45rpm

Posted: Sun Jun 18, 2017 3:25 pm
by block
Bought a systemdek iix900 for a spare system. Wanted to buy a cheap tt to play with and it seems to have good reviews but maybe I should have started with rega.

Plays 33rpm at the upper rotating pulley, I think you call it, ok.

But when I change the belt to the lower 45rpm the belt starts to move up as the platter rotates and the belt either ends up coming off or goes into the 33rpm.

I googled the problem and there seems to be a fix/adjustment but I don't really understand. Its something about a grub screw located between to screws which I found but don't know how to adjust it to raise the pulley.
Do get access to it by removing the base?



"Postby wobbleu » 30 Jul 2008 23:07
Larz
If you look at the top of the plinth in the rear left corner - you'll see 2 screw heads (these hold the motor frame in place) - between the two screws and bit more to the back there's a hole in the top-plate. Inside that is a grub screw which can be adjusted to set the angle of the motor assembly - if you adjust that you'll get the belt running true without affecting the 5mm gap.

You might find it easier to loosen the motor frame screws 1/2 a turn before you adjust it - and then tighten them up when it's set right.

It can be done with the platter in place too....

Adjust the suspension on a TT from the bottom ? whose stupid idea was that then? some TT designers get it right :D

regards C"

Re: Help! Belt coming off at 45rpm

Posted: Sun Jun 18, 2017 4:11 pm
by Fran
Can you see the 3 screws he's talking about - the two that hold the motor and the hole for access to the grub screw beneath. Juding by his description you don't need to go at it from the bottom.

Re: Help! Belt coming off at 45rpm

Posted: Sun Jun 18, 2017 7:17 pm
by block
Hi Fran
Yes I can see 2 screws holding the motor I think holding the motor to the top wooden base. The middle is a hole which I presume is a grub screw which I don't have a clue what you use to adjust.
Now looking closely I think an Allen screw is missing as well holding the chassis? There's a simple instructions manual calling it the " chassis adjustment point"
There's 3 of them and one of the Allen screw is missing. I think the hole on the top base is not aligned with the hole at the bottom where the missing screw is.

Can I unscrew one of the other screws and get a replacement screw and this is the problem? Because aligning the holes seem to tug on the belt a bit making it tighter.
Though from the eye it does look quite low.
The guy selling it said he did all the adjustments and is ready to play. I think he only fiddled about the arm.

Re: Help! Belt coming off at 45rpm

Posted: Sun Jun 18, 2017 9:37 pm
by Fran
I'd say its a fairly standard grub screw so if its missing you should be able to pick one up fairly easy on ebay or whatever. You might even be able to get a sampler pack of them so you'd have a variety. As I understand it the motor is held with the 2 mounts, and the grub screw provides adjustment to get the tilt right so that the belt runs in the middle of the pulley.