Regular - yet irregular - thump from Garrard 301

[immac]

Hello Art of Sound members,
I have a Garrard 301 MKII (oil-bearing) which has been sat in a cardboard box for at least a decade awaiting some love. Recently I've taken it out and given it to a relative for a once over. He is a hi-fi engineer of no little experience. He reports back - the motor is quiet and holds its speed perfectly. But there is a knocking noise, apparently emanating from the idler mechanism.
At first, he thought 'bent idler'. However, it didn't look damaged. And then when he went away and then came back and switched on the deck again - it didn't make the noise. And we discovered that sometimes it knocks, sometimes it doesn't. In all other respects, everything is in working order. If it was a bent idler spindle, surely it would make the noise all the time. Any ideas as to what it could be? We are baffled.
All suggestions very gratefully received.
Thank you
Immac

[DSJR]

The forum police will be after you if you don't tell us something about yourself - where you hail from, your system and musical tastes...

The idler SURFACE may want cleaning as the slightest bit of grit partially emedded will cause this. Also the driving surface of the rubber may need to be "evened out" by cleaning, as I remember from my idler days a regular "swishing" noise caused by contaminated idler drives (the auto mech in a Collaro Conquest was driven by a separate idler and these used to make the most horrid swish-swish noises when cycling).

By the way - welcome

[Alex_UK]

Hello & welcome, + what Dave said to tip you the wink about forum etiquette if you could be so kind.

Primalsea (Paul) suggested a good remedy in this thread/post http://theartofsound.net/forum/showp...5&postcount=13 if the actual idler wheel rubber is in any way suffering. But why it only happens sometimes, I wouldn't have a clue - sure one of the more knowledgeable Garrard owners than me the "vinyl numpty" will be better placed to assist further.

[Spectral Morn]

Hello Art of Sound members,
I have a Garrard 301 MKII (oil-bearing) which has been sat in a cardboard box for at least a decade awaiting some love. Recently I've taken it out and given it to a relative for a once over. He is a hi-fi engineer of no little experience. He reports back - the motor is quiet and holds its speed perfectly. But there is a knocking noise, apparently emanating from the idler mechanism.
At first, he thought 'bent idler'. However, it didn't look damaged. And then when he went away and then came back and switched on the deck again - it didn't make the noise. And we discovered that sometimes it knocks, sometimes it doesn't. In all other respects, everything is in working order. If it was a bent idler spindle, surely it would make the noise all the time. Any ideas as to what it could be? We are baffled.
All suggestions very gratefully received.
Thank you
Immac

Please pop into the Welcome section and tell us a wee bit about yourself, taste in music and your system.

Oh yes and can you make your first (real)name your signature please.

Thank you in advance and Welcome to AOS


Regards D S D L

[immac]

Hi

Thank you for your generous replies thus far. I am surprised at how rapid the response has been.

I thought I had put stuff in my profile. Am I missing something? Apologies if I have.

Funny how everyone assumes that Immac is not my real name...

[Spectral Morn]

Hi

Thank you for your generous replies thus far. I am surprised at how rapid the response has been.

I thought I had put stuff in my profile. Am I missing something? Apologies if I have.

Funny how everyone assumes that Immac is not my real name...

Ian

Hi Ian new members are asked to pop into the Welcome section of the forum (http://theartofsound.net/forum/forumdisplay.php?f=15) and say hello first etc as it is nice to be able to get to know new members before launching into audio chat.

Regards D S D L

[John]

The forum police will be after you if you don't tell us something about yourself - where you hail from, your system and musical tastes...

The idler SURFACE may want cleaning as the slightest bit of grit partially emedded will cause this. Also the driving surface of the rubber may need to be "evened out" by cleaning, as I remember from my idler days a regular "swishing" noise caused by contaminated idler drives (the auto mech in a Collaro Conquest was driven by a separate idler and these used to make the most horrid swish-swish noises when cycling).

By the way - welcome

Dave welcome to the forum police

[John]

Hopefuly Clive might be able to advise as he has a 301

[Clive]

It could be that the idler rubber has a ding in it, often they can be teased out with some manipulation (best done with the wheel removed). Could be that bearing on the idler is duff. Check with Perfect Sound for spare parts, if they are needed.

[gortnipper]

As Clive says - check the idler wheel for flat spots or if it is hard - it should be soft and supple. The inside of the platter should be clean and free of debris. If not, clean both with isopropyl alcohol (not rubbing alcohol).

Check also its alignment (with the platter off) as it engages the various steps of motor pulley when set to different speeds. It should be centred on the appropriate step, and not rub on the one above/below it.

Check also the eddy current brake mechanism (the magnet attached to mechanism controlled by the fine speed adjustment knob). Sometimes the disc on the motor spindle rubs on the eddy current brake.