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Latest post 03-07-2012 8:54 AM by NormanGrey. 10 replies.
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  • 02-17-2012 4:42 AM

    • NormanGrey
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    • Sydney, Australia
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    4002 Ignoring record on platter

    Hi Guys,

    Got a 4002 that up until recently was working fine. Had a small problem with the stylus arm lowering and raising too slowly so used a drop of lubricant to loosen it up. That worked but now the turntable doesn't recognise that there's a record on the platter and simply runs the arm to the end of its path and then returns to off. I know the light is working on the sensor arm but don't know where the light is picked up from. Any ideas welcome.

     

    Regards,

     

    Norman Grey

  • 02-17-2012 7:43 AM In reply to

    • Step1
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    Re: 4002 Ignoring record on platter

    Can you manually cue the arm onto the record?

    Olly.

  • 02-17-2012 5:13 PM In reply to

    • NormanGrey
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    • Sydney, Australia
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    Re: 4002 Ignoring record on platter

    Thanks Olly,

    Yes, I can stop the arm moving by using the lift buttons and then lower the arm onto the record and fast forward, backward, etc. I have a suspicion I have got some lubricant where I shouldn't have, but don't where to look.

    The other worrying thing is that if I press OFF during play the arm seems to start moving back to the dock before it has lifted fully - ouch!

    Norman

  • 02-18-2012 6:19 AM In reply to

    • Step1
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    Re: 4002 Ignoring record on platter

    ok if the arm is slightly sticking down this is normally as a result of the L shaped bracket that transmits solonoid / damper movement to the actual arm. I don't recomend you remove the sensor arm assembly to access the pivot unless, 1. you can find no other way to free the pivot 2. and / or the sensor arm is not aligned as per the service manual. IMO it is tricky to achieve this accurately and also means you have to go through a lengthy setup after so best to try feeding some good quality machine oil into the pivot and seeing if this will free it. Not ideal but should be enough. The pivot is tucked up in the arm assembly move the solenoid arm with your finger to trace where it is...

    Regards the other fault I will have a think about that... Could be the light source in the position sensor so you need to look at the perspex ruler to see if all is ok there. The light source will either be incandescent (and visible) or infra-red and only visible to a video camera...

    I am just off out so that is all I can suggest for now...

     

    Olly.

  • 02-18-2012 7:10 AM In reply to

    • NormanGrey
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    Re: 4002 Ignoring record on platter

    Thanks Olly,

    The turntable at present is sitting in its cabinet, so tomorrow I'm going to take it out and sit it on the table where I can work on it properly. Haven't really delved into these things before so am unfamiliar with the components - but, willing to give it a shot. I have a copy of the service manual but it's very poor quality. If you could give me an image of the component I need to work on rather than a name that would be great, or I could post some images and give you a better idae of what's going on. Are we allowed to post images in this forum?

    I have lots of oil in the garage but the finest I can think of is for my air-staple gun - a very light machine oil I think but I can purchase whatever you think might be best.

    The light source - if you're talking about the light at the end of the sensor arm - is incandescent and plainly visible when the turntable is on. Where's the perspex ruler?

    Thanks again, could take a while this as I'm nine hours ahead of you but really want to get it sorted.

    Norman

  • 02-18-2012 11:08 PM In reply to

    • NormanGrey
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    Re: 4002 Ignoring record on platter

    Bit of an update,

    Assuming the perspex ruler is the graduated perspex about three inches long that moves along with the arm, it looks to be ok. There seems to be a very small light globe on the end of two right-angle pins behing the perspex that doesn't light up from what I see. I can get a reading of 1.2 volts across the solder terminals but no continuity across the pins so am assuming there's something amiss there.

    Interestingly, the turntable changes to 45rpm as it should when it doesn't sense a record on the platter and I would have thought that would require the light sensor to be working.

    The stylus arm seems to have loosened up considerably and is now 'flicking' itself up when I press off rather than dragging itself up.

    Thanks for any help.

    Norman

  • 02-18-2012 11:15 PM In reply to

    Re: 4002 Ignoring record on platter

    Here's some good reading,

    http://www.condoraudio.com/

    look to the right side of the web page for Beogram 4002

     

    Roy Albuquerque, NM

  • 02-18-2012 11:56 PM In reply to

    • NormanGrey
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    Re: 4002 Ignoring record on platter

    Thnk you. Looks good! Will work my way through it and see what I can find.

  • 02-19-2012 4:33 AM In reply to

    • Step1
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    Re: 4002 Ignoring record on platter

    ok the posistion detector is just fine then, as the long black stripe is responsible for the speed change.

    Which type number is your deck? There are a couple of transistors and capacitor etc.. that are responsible for sending the drop command to the relavent circuit in my diagram c20 tr7 and associated components. You need to check that transistor, capacitor and other components in that part of the circuit. If ok you might need to start measuring while the beogram does its stuff...

    Olly.

  • 02-19-2012 4:54 AM In reply to

    • NormanGrey
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    • Sydney, Australia
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    Re: 4002 Ignoring record on platter

    Deck is 5511. After playing around all day balancing, cleaning, etc I still have a functioning deck - up, down, sideways, just no automatic dropping of the arm. Please bear in mind my knowledge of pcb's etc is limited to measuring voltage and crude soldering, anything else requires instructions - be kind.

    Norman

  • 03-07-2012 8:54 AM In reply to

    • NormanGrey
    • Not Ranked
    • Joined on 02-17-2012
    • Sydney, Australia
    • Posts 7
    • Bronze Member

    Re: 4002 Ignoring record on platter

    Well, after all my lubricating and cleaning the problem still exists. No rush on this though as I have recently bought a replacement turntable, but it's something I'd like to try and fix if possible.

    Norman

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