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#1
Posted to rec.audio.high-end
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Thorens 145 hum
Picked up a used TD145. Thought it was a bargain.
But when the arm approaches the last track it will often go to a loud hum with no discernable audio. Could this be the arm wiring? Is this a problem you've noticed or has been documented before? |
#2
Posted to rec.audio.high-end
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Thorens 145 hum
On Thu, 26 May 2011 19:41:34 -0700, Cheesehead wrote
(in article ): Picked up a used TD145. Thought it was a bargain. But when the arm approaches the last track it will often go to a loud hum with no discernable audio. Could this be the arm wiring? Is this a problem you've noticed or has been documented before? Yes It is the wire and yes I've seen it before on other 'tables. Usually it's caused by a wire being twisted as the arm traverses the record at some point causing a broken connection. Often it's the shield that parts, or perhaps something shorts-out. You'll have to look. Best to remove the wires from the cartridge and using an ohm meter, ring out each wire in turn while moving the arm about and noting which wire loses continuity at some point in the arms traversing arc. If you have to get the internal wiring replaced, you likely cannot do that yourself, and it might not be worth having it done, even if you can find somebody in this day-and-age who knows how. |
#3
Posted to rec.audio.high-end
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Thorens 145 hum
On Fri, 27 May 2011 06:00:10 -0700, Audio Empire wrote
(in article ): On Thu, 26 May 2011 19:41:34 -0700, Cheesehead wrote (in article ): Picked up a used TD145. Thought it was a bargain. But when the arm approaches the last track it will often go to a loud hum with no discernable audio. Could this be the arm wiring? Is this a problem you've noticed or has been documented before? Yes It is the wire and yes I've seen it before on other 'tables. Usually it's caused by a wire being twisted as the arm traverses the record at some point causing a broken connection. Often it's the shield that parts, or perhaps something shorts-out. You'll have to look. Best to remove the wires from the cartridge and using an ohm meter, ring out each wire in turn while moving the arm about and noting which wire loses continuity at some point in the arms traversing arc. If you have to get the internal wiring replaced, you likely cannot do that yourself, and it might not be worth having it done, even if you can find somebody in this day-and-age who knows how. I'd like to add, that while it COULD, conceivably, be the cartridge, itself, it's unlikely. Reason? Usually the cartridge connections (internal and external), don't move in relation to the arm, so were it the cartridge, the hum probably wouldn't be related to the POSITION of the arm relative to it's position on the record, but rather would either randomly come and go, or be bad all the time. The exception might be if the cartridge itself were a moving coil and the greater skating force toward the inner-grooves pulls on one coil lead more than another causing a loss of connection on one of the channels. Moving magnet or moving iron (variable reluctance) types of cartridges have rigidly mounted coils and they don't ever move relative to the cartridge body. |
#4
Posted to rec.audio.high-end
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Thorens 145 hum
I think it is shutoff circuit.
I'm going to look into a bypass or repair.u On May 27, 12:33=A0pm, Audio Empire wrote: On Fri, 27 May 2011 06:00:10 -0700, Audio Empire wrote (in article ): On Thu, 26 May 2011 19:41:34 -0700, Cheesehead wrote (in article ): Picked up a used TD145. =A0Thought it was a bargain. But when the arm approaches the last track it will often go to a loud hum with no discernable audio. Could this be the arm wiring? Is this a problem you've noticed or has been documented before? Yes It is the wire and yes I've seen it before on other 'tables. Usuall= y it's caused by a wire being twisted as the arm traverses the record at some = point causing a broken connection. Often it's the shield that parts, or perha= ps something shorts-out. You'll have to look. Best to remove the wires fro= m the cartridge and using an ohm meter, ring out each wire in turn while movi= ng the arm about and noting which wire loses continuity at some point in the a= rms traversing arc. If you have to get the internal wiring replaced, you li= kely cannot do that yourself, and it might not be worth having it done, even= if you can find somebody in this day-and-age who knows how. I'd like to add, that while it COULD, conceivably, be the cartridge, itse= lf, it's unlikely. Reason? Usually the cartridge connections (internal and external), don't move in relation to the arm, so were it the cartridge, t= he hum probably wouldn't =A0be related to the POSITION of the arm relative t= o it's position on the record, but rather would either randomly come and go, or = be bad all the time. The exception might be if the cartridge itself were a moving coil and the greater skating force toward the inner-grooves pulls = on one coil lead more than another causing a loss of connection on one of th= e channels. Moving magnet or moving iron (variable reluctance) types of cartridges have rigidly mounted coils and they don't ever move relative t= o the cartridge body. |
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