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Beogram 6500 odd sound

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cmsammy
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cmsammy Posted: Mon, Apr 2 2018 5:56 PM

My record deck has developed an annoying additional beat.

Its almost as if the record is scratched except that the noise is a light thump, not a click. It sounds like someone is tapping the deck whilst it's playing. I've replaced both belts with B&O belt bought from Martin and lubricated the slider, I've also made sure it's completely level but still it persists. The cartridge was rebuilt just 3 years ago by Axel with a Shibata diamond stylus and has been used regularly but not extensively. 

I have selected vinyl which is well centred so there is not excessive side to side movement of the arm, if I had to spell the noise I'd go with "dmp" 

Any suggestions

 

 

solderon29
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Does it do it all the way across the record or just towards the centre?I've seen several cases where the new heavyweight discs can rub on the deck plate if  there is an imperfection(not uncommon!) in the disc pressing.The combined weight of the disc and the carriage,lower the transport at the middle of the record.

You should have a couple of millimetre clearance between the record and the deck plate.

Check it with the unit unpowered,and with a record in place,then slide the pu arm carriage across the disc towards the label.Check the clearance again when spinning the record manually

If the record touches the deck anywhere,tweak the transport height adjusting screw's as appropriate.

Nick

cmsammy
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cmsammy replied on Tue, Apr 3 2018 9:58 PM

Hi Nick, 

It does it right from the start on old vinyl I've played many times. It doesn't look to be touching but I'd say the clearance is less than 2mm.

Where are the adjustment screws you mentioned ?

 

 

solderon29
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If you lift off the platter,you will see the bronze coloured suspension plates/springs,and their adjustment screw's which are accessable through holes in the deck plate.The adjustment is quite critical,you won't need to  turn the screws much to raise the height.Clock wise to raise.Check that the platter is level afterwards.

While the platter is off,check that the skeletal turntable underneath, does not touch any cables or it's locking posts when you turn it manually.Something like that could easily explain your mystery noise.

If the noise frequency coincides with the turntable speed,this would be another clue.

Nick

Beobuddy
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Watch closely if the needle lifts a bit in it's system when the neeldle arm lowers.

Sometimes this doesn't happen and the needle keeps bumping to it's housing.

cmsammy
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cmsammy replied on Thu, Apr 5 2018 7:14 PM

I've looked at the height adjustment and the vinyl is clear all the way around so that does not appear to be the problem. I have taken the cartridge off and the suspension seems smooth in all directions.

I know vinyl is rarely perfectly centred and the arm has to "ride" up/down left/right with the track but it appears to be this movement causing the sound. 

I'd try and live with it if is were only audible between tracks but it can be heard through the music and obviously gets louder when turned up

 

 

Weebyx
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Weebyx replied on Fri, Apr 6 2018 6:26 AM

cmsammy:

I've looked at the height adjustment and the vinyl is clear all the way around so that does not appear to be the problem. I have taken the cartridge off and the suspension seems smooth in all directions.

I know vinyl is rarely perfectly centred and the arm has to "ride" up/down left/right with the track but it appears to be this movement causing the sound. 

I'd try and live with it if is were only audible between tracks but it can be heard through the music and obviously gets louder when turned up

 

So it is a noise that is amplified and gets louder with the music ? I thought it was a physical sound form the deck ?

If it is a noise that is amplified and heard in the speakers, then the pickup is defect somehow.

/Jacob

cmsammy
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cmsammy replied on Sat, Apr 7 2018 12:02 AM

I was really hoping that would not be the answer, 3 years is a pretty poor return on that investment 😔

solderon29
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What is the frequency of the noise,ie,does it occur once every turn of the turntable say?Alternatively,does it do it everytime the pu arm carriage is moved forward while playing.You can see this if you watch the carriage moving gently to keep the arm tracking while playing.If the noise occurs then,it would suggest it is coming from the servo motor.

Martin(Dillen) makes a replacement drive belt for this motor that is a replica of the original,ie,triangular in cross section.Some aftermarket belts are too tight and can put a load on the motor,and cause odd noises between tracks.Martin's belt overcomes this problem.

Yes indeed,it could be the pu,but the only way to prove it would be to try another .

Regards,

Nick

MediaBobNY
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Possibly it's this problem, and the fix is a replacement motor from a donor turntable

cmsammy
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cmsammy replied on Mon, Apr 9 2018 5:00 PM

I replaced both belts with ones I bought from Martin. The frequency is most, but not every turn of the deck.

cmsammy
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cmsammy replied on Mon, Apr 9 2018 8:29 PM

Having watched the arm closely I'm pretty sure the noise coincides with each movement of the transport arm (rather than the cartridge arm).

This brings me back to my first thought that the slider rail needs lubricating. However the movement is so minute it's hard to be 100% certain. Think I'll try again

solderon29
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solderon29 replied on Tue, Apr 10 2018 11:57 AM

The arm carriage servo does operate roughtly every turn of the turntable,so this could be significant.

I don't think it's the guide rails,but it could be the servo motor bearings as mentioned above.

They can and do dry out of course.You could try a little drop of sewing machine oil on the end of a straightened paper clip,to get the oil into the bearing behind the pulley.

Here is what must seem a silly question too,but are the transit screws underneath the unit,turned fully anti-clockwise?

Nick

cmsammy
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cmsammy replied on Tue, Apr 10 2018 9:38 PM

The transit screws have been where they are for about 25 years an this noise has been around for about 6 months. I'm guessing that  probably rules them out.

cmsammy
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cmsammy replied on Sat, Sep 29 2018 6:06 PM

I know I raised this ages ago but I have only just got around to getting the screwdrivers out. I now know exactly what is causing the noise I just need to know how to stop it.

The indicator arm is the cause, by applying pressure to the side it stops the noise, it appears to be dragging behind the tone arm. I've lubricated the sliders but still it "bomps" each time it moves. Is there an adjustment that's out ? Any ideas ?

cmsammy
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cmsammy replied on Sat, Sep 29 2018 6:06 PM

I know I raised this ages ago but I have only just got around to getting the screwdrivers out. I now know exactly what is causing the noise I just need to know how to stop it.

The indicator arm is the cause, by applying pressure to the side it stops the noise, it appears to be dragging. I've lubricated the sliders but still it "bomps" each time it moves. Is there an adjustment that's out ? Any ideas ?

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