Turntable Slipping clutch

by **atavid** » 03 Feb 2009 08:48

Has anybody with an Ariston RD11s solved the problems associated with this TT's quirky motor pulley/clutch mechanism.Long ago the original felt washer disintergrated and i've had mixed success at making up new ones out of various bits of felt i've had lying around,however as i say, the result is not always completely successful resulting in clutch slip or refusal by the clutch/ motor to start turning the platter.
I've tried stretching the small tapered spring to add more drag, i've tried roughing up the surfaces of the pulley and small 'd' washers,but nothing i do seems to fix the problem effectively.I'm really struggling to understand what should be quite a simple mechanism and at an even greater loss to make it work.In desperation and sheer frustration i even tried locking the pulley to the motor shaft and doing away with the clutch altogether,but the motor just wont start the platter turning.Any thoughts would be welcome.

by **atavid** » 07 Feb 2009 01:02

Looks like im the only Ariston owner in the world to have experienced this problem.Surely the felt washer on other RD11s' must have worn out by now.

by **bena** » 07 Feb 2009 13:29

I can't picture the problem atavid, can you post some pics?

Ben

by **atavid** » 08 Feb 2009 13:51

Hi Bena,how ya doing? Meant to say thanks some time ago for posting those great shots of the innards of your turntable.Really interesting design.
I've spent most of today stuffing around with this bl**dy clutch mechanism and worked out part of the problem.When i put in the new Linn motor i had to replace the original spongy gasket between the motor mounting brackets and the frame that actually holds the motor in place.Of course i didnt have an original gasket to use so i made one up.Seems though, that i made it a little thicker than the original and this made the motor sit a little lower under the top plate.This caused the pulley to be lower than the inner platter and thus the belt was trying to turn but being pulled upwards at the same time.
I've fixed that now and its a little better overall, but the clutch still wants to slip at start up and will continue to unless i give the platter a good spin up to speed by hand first.
I think i need to find the correct grade of felt to make the clutch washer out of.
I'm also considering modifying the motor attaching holes and filing them slightly longer in a short arc so that i can adjust the belt tension and platter speed by slightly moving the motor further away from the platter.Not sure about this one yet.I know that the belt itself is also having an effect on this problem.Again i'm considering something radical here and thinking about trying a silicon belt instead of the square section belt.
I also realise i'm probably babbling on to myself here since no one else seems to have experienced this issue or finds it of much interest,but mabye my findings will come in helpful to some poor sod one day who finds himself going through all the s**t i've been through with it in the last few weeks.
Bena,i'm without digital camera at the moment.Seems my trusty Canon also decided to pack it in.I'll try and post pics later if i dont have any luck in solving the issue once and for all.

by **Alec124c41** » 08 Feb 2009 23:32

Note that a flat belt will make your platter turn slower than the square belt.

Cheers,
Alec

by **bena** » 09 Feb 2009 22:57

Hi mate

No probs on the pics, glad you saw them.
Sorry I'm really not that familiar with your deck and mine doesn't seem to have anything like a clutch setup

It sounds like the material the clutch is made off is pretty important, like it allows a limited amount of slip? Is it something that could be removed from the system to prevent issues in the future, ie. adapt it so its just a pulley and belt?

by **alanomt** » 13 Feb 2009 12:44

Hi, I have had some 'judder' when the motor started, used to shake the tone arm. stripping the pulley assy and reassembly (without any oil) has cured the problem and it now starts, quickly and smoothly. I seem to recall that the components of my pulley assy differed from that shown in the service sheet.

regards

Alan

by **alanomt** » 13 Feb 2009 13:03

Have added pictures to Ariston gallery

by **atavid** » 14 Feb 2009 03:50

Thanks for the replys guys.
Alanomt can you tell me what type of material your clutch uses,and approximately how thick it is.That would be a big help.Also what is the freestanding height of the cluch spring??
Does your platter ever require you to kick start it turning by manually spinning up the platter by hand??

by **alanomt** » 14 Feb 2009 11:15

Hi, washer is felt, 0.426 od, 0.046 thick, remember that this is probably the original. spring 0.220 free. I have posted pics in the ariston gallery. You can see the components, on my deck the plain washer is next to the spring, then the pulley, felt washer, 'D' washer and finally circlip. No lubricant. Having stripped it for the pics and reassembled it's fine, no assistance has ever been required for the turntable to start.

Good luck

Alan

by **atavid** » 15 Feb 2009 06:53

Thanks for the pics Alanomt,thats really interesting the way yours is set up.My Ariston owners manual shows that the clutch should be assembled as follows:
Flat washer down over the motor extension spindle(if you have brass pulley)
Brass pulley next over spindle
Felt washer next on top of pulley
Next a 'D' shaped washer
Then the spring (widest diameter to bottom)
Again another 'D' washer
Finally the circlip
Of course ive been assembling it that way,but perhaps Ariston experimented with alternative ways of assembling the clutch mechanism.
Do you have a manual with a diagram showing the clutch assembly?

by **alanomt** » 15 Feb 2009 10:42

Hi, the only manual that I have is the one downloaded from this site. My deck is still using the original motor, I believe that the ariston platter assy is heavier than a linn, I'm sure that someone will confirm/dispute that, maybe your motor does not produce enough torque. I do not know if the od of the inner platter is the same as a linn, if it is then perhaps you could change the motor pully to a linn one and then use a flat belt.
I also have an Ariston RD110SL, this has a flat belt drive, with just 'talc' to create start up slip.

Alan

by **atavid** » 15 Feb 2009 12:49

I will check that manual again but from memory i dont think it shows the illustration that my manual has in it. Yes i also believe the platter assembly is substantially heavier than a Linn,again from memory as a friend i know had one until fairly recently.
There is a small difference in the inside platter size but cant recall which way or by how much.
I recently replaced my motor with a new (supposedly) higher torque Linn motor.
Ive considered doing the flat belt change but as you say it would require some machining and calculation to get the whole thing exactly right.In view of your success with having the clutch spring under the pulley i thought i might experiment with this later this week and see what happens.Im also going out to see if i can purchase some rough felt to make a new washer.

by **marcoselvaggio** » 12 May 2009 07:36

Hi Atavid

I have an RD11 and have similar issues to yours. The pulley assembly on mine was missing the clutch bits other than the felt washer. Once I had replaced the belt (square cross-section) and cleaned the motor spindle, the pulley wheel would grip just enough to keep it spinning - though it was very slow to come up to speed. Over time, however, the speed of the motor has seemed to slow noticeably. I lined the pulley wheel with a couple of winds of that white plumbers tape to speed it up and this worked, but then I found that the pulley wheel started to slip on the spindle (remembering that I have no clutch assembly)...so finally I wraped the motor spindle with a little of the tape to provide grip and now it will hold...the only remaining problems are, firstly, that the platter is so heavy that the motor will not start it spinning unless I help it along (as you mentioned) and when it spins it plays ridiculously slowly and will not get up to playing speed of its own accord....however if I give it another push along it will get up and hold the right speed. In other words the motor seems to be running with vereerrryy lloooowww torque. All very frustrating as I actually love the sound when it gets going.

If you have any ideas on what I could do I would really appreciate it.

Regards
Mark