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LPT Motor Pulley

Posted: 12 Feb 2019 10:20
by Bryanwalsh67
Hi - just copying a post I put in the generic turntable forum. I have what I hope is a minor issue with my LPT. There is what sounds like the motor pulley catching / fouling on either the plinth or underside of the platter. It is only the slightest contact, but if I give the lightest push of the plinth towards the back of the turntable it gets worse and noticeably slows down the speed. Is this a case of getting the mounting of the pulley adjusted (I wouldn't dare do this myself) or is there anything I can do myself? Thanks!

Re: LPT Motor Pulley

Posted: 12 Feb 2019 11:36
by abril
Hi again

Just remove the platter ,secure the arm and stylus and lift off the top plate with the main bearing.
This can be a little awkward sometimes as the posts don't want to come out if the top plate is not lifted square.
Underneath you will find 4 posts on rubber isolation grommets,these have a threaded insert on the top - turn each threaded insert anticlockwise by one turn and reposition the top plate.
That should have lifted the whole top plate with the main bearing and arm by about 1mm.

Re: LPT Motor Pulley

Posted: 12 Feb 2019 11:40
by Bryanwalsh67
Thank you Abril

So you think the issue is the top plate has sagged a bit over time and the pulley is catching the underside of the platter?
abril wrote:
12 Feb 2019 11:36
Hi again

Just remove the platter ,secure the arm and stylus and lift off the top plate with the main bearing.
This can be a little awkward sometimes as the posts don't want to come out if the top plate is not lifted square.
Underneath you will find 4 posts on rubber isolation grommets,these have a threaded insert on the top - turn each threaded insert anticlockwise by one turn and reposition the top plate.
That should have lifted the whole top plate with the main bearing and arm by about 1mm.

Re: LPT Motor Pulley

Posted: 12 Feb 2019 11:42
by abril
May have been set very close and a little disturbance from being moved may have been enough to make it touch.
Give me an hour and I'll put some pics up.
44035
44036

Note the post on each corner of the base.
Ignore the motor and circuitry as it's my DC motor conversion.

Re: LPT Motor Pulley

Posted: 12 Feb 2019 14:22
by Bryanwalsh67
Thank you so much. I will probably let my hifi specialist who supplied the deck to me have a look at this. In the meantime, is my 'inserted folded card in the gap' going to compromise sound quality?

Re: LPT Motor Pulley

Posted: 12 Feb 2019 14:37
by abril
Shouldn't think so.

Re: LPT Motor Pulley

Posted: 12 Feb 2019 15:53
by Bryanwalsh67
Thank you Abril. 👍

Re: LPT Motor Pulley

Posted: 12 Feb 2019 15:58
by abril
It may also be that the motor mount is not quite square and is leaning in towards the belt driven diameter as there is not much clearance there with the pulley flange.
When you push the top plate back it pushes the platter towards that flange????
Just a thought.

Re: LPT Motor Pulley

Posted: 12 Feb 2019 16:35
by Bryanwalsh67
Yes I see your point. Only the slightest bit of contact is being made so we must be into a millimetre....!

Re: LPT Motor Pulley

Posted: 15 Feb 2019 11:05
by Bryanwalsh67
Quick question if you have a moment. Does the presence of a clear acrylic (red/green light) power knob indicate that my LPT is the GTI psu version? (Standard psu has a black switch with LED next to it?)

Re: LPT Motor Pulley

Posted: 15 Feb 2019 14:39
by Quakee
Yes , GTI version .