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Dual 505-4 help needed [message #11872] Fri, 28 January 2005 08:22 Go to next message
oxymoron is currently offline  oxymoron
Messages: 3
Registered: May 2009
Esquire
I have a Dual 505-4 turntable that has two annoying habits.
1. After a period of time a buzzing noise will occur from the speakers and can only be cured by switching it off.(I have an earthing lead connected to my amplifier, and I have made no modifications or upgrading to this deck)
2. When switching between 33 & 45 it sometimes stays at 33 and I have to remove the platter before it will change.
I hope someone can give me help with either of these issues.
Apart from these two small faults it is an excellent deck and I would recommend it to anyone that has a small budget for a turntable.

Re: Dual 505-4 help needed [message #11875 is a reply to message #11872] Sun, 30 January 2005 09:34 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18793
Registered: January 2001
Illuminati (33rd Degree)
What do you shut off to cure the buzzing noise? The turntable or the amp or preamp?

About the speed change, it sounds like it may be mechanically hung. Have you tried cleaning the mechanism?

Re: Dual 505-4 help needed [message #11876 is a reply to message #11875] Sun, 30 January 2005 09:46 Go to previous messageGo to next message
oxymoron is currently offline  oxymoron
Messages: 3
Registered: May 2009
Esquire
Just stopping the turntable causes the hummimg to stop. As for the speed change mechanism, I haven't cleaned it. Any tips on how best to do this would be appreciated.

Re: Dual 505-4 help needed [message #11877 is a reply to message #11876] Sun, 30 January 2005 10:04 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18793
Registered: January 2001
Illuminati (33rd Degree)
Stopping the turntable - You mean physically stopping the platter? Are you saying that even if power is applied, once you stop the platter the hum stops? Or does it happen when you shut off? In other words, is this hum maybe related to the drive motor?

In any case, I'm thinking it might be a good idea to clean the mechanical connections, such as the wires to the cartridge and any other removable fittings or crimp connections.

Re: Dual 505-4 help needed [message #11878 is a reply to message #11877] Sun, 30 January 2005 13:22 Go to previous messageGo to next message
oxymoron is currently offline  oxymoron
Messages: 3
Registered: May 2009
Esquire
Actually touching the platter can make it hum louder. I just switch it and the amp off when it does this. As far as i can tell it only does this when the platter is moving.

Re: Dual 505-4 help needed [message #11879 is a reply to message #11878] Sun, 30 January 2005 23:45 Go to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18793
Registered: January 2001
Illuminati (33rd Degree)
I see. Whan you stop the platter or increase drag on it, this makes the motor draw more current. That leads me to believe that you might have a ground loop that is causing motor power current draw to introduce noise onto the signal line. Have you tried isolating the cartridge signal wires? Are any of those four wires connected to the chassis? Could one of them be touching?

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