Thorens TD160 hum and set up

johnnyboy114

Standard Member
Hi

I am new to this forum but a bit desperate for answers.

Me and my now recently deceased father have passed between us the family Thorens TD160 over the years. Was bought by my Dad the year I was born, 1972. I suspect it's never had a service in this time but was kept almost mint and used a lot by myself when I "acquired" it in the 90's. Anyway, sterling service, never missed a beat.

But hasn't been used for a while due to a bent motor spindle. I have replaced this but have noticed a significant sagging to the left hand side of the platter. I replaced the springs but just can't seem to set it up correctly.

Also, since then, on my Arcam Alpha 5 (built in phono), there is a loud hum that gets louder with the volume. It's more background than intrusive but it's there and what's more, when I depress the DIRECT button the amp, the hum gets worse. It's no bad thing the hum is at its best when the DIRECT button is pressed in, but is this something significant of note? The hum was not there a few years ago before it was taken out of service for a little while

I know my Dad replaced both the power cables and the RCA cables, but as I don't have a wiring diagram and I am absolutely not an electrical engineer, I have no idea where this hum has come from or why it is there.

I checked the plug (British 3 pin) and the wire is a simple 2 core, not a grounded 3 core wire. Is this significant? If so, how would I wire this to help eliminate the hum, or do I have a more significant problem. I am currently only running an Ortofon 3E cartridge just to get it set up correctly but this has been on a while and wasn't humming before, so suspect this is wired correctly and not the route of the issue. I am happy to be corrected.

Any help on this would be massively appreciated. It really want to get this turntable back up and running for my Dads sake as much as my own. I have adored it all my life. I don't want to see an ignominious demise for it. It means a lot.

I have attached photos of wires as I can see them but suspect won't help a lot

Thanks in advance

John
 

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Deleted member 781788

Guest
The mains plug does not need or want earth wiring. this is to avoid earth loop that could cause hum!
The tonearm wiring looks a little cheap and un-proffessional.
This is how to remedy the situation:
- use a soldering iron to connect the two screen wires (inside wires on your third picture) together, and also solder a piece of single cable, as long as your phono cable (+10cm) to the same point.
- for absolute isolation, you could put insulating tape over the solder points, and wrap tonearm thin wires and the solder assembly in Alu foil neatly . make sure you connect the foil to the same ground point as the single cable, somehow.
- Route the single cable along the phono cable. and connect the other end to your amp's ground .
There is brass thumb screw at the back for this purpose.

You could lift the inner platter gently out. Use a paper tissue dampened in white spirit and clean the shaft, treating it with respect all the time. Also clean the bearing socket using another paper tissue soaked in WS - just twist the tissue into a long piece and clean the hole out using a twisting action. Drop a couple of machine oil onto the hole and two more drops on the platter shaft. Carefully guide the shaft back in. At this point you might notice that you have air trapped in - no worries just spin the platter and give it a minute or so - it will go down. Clean the motor spindle the same way.
If the belt is too loose, get another from ebay.

Happy listening.
 
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Stinger69

Active Member
I don't see an earth lead exiting with the signal leads. Is there one, and is it connected to the amplifier?
 

BlueWizard

Distinguished Member
Perhaps I'm interpreting what I am seeing incorrectly, but it looks like he used common lamp cord to replace the wiring. The Signal Wires need to be shielded, at is appears they are internal to the case. But again, perhaps I'm not interpreting what I see correctly.

If Hum comes on suddenly, it probably means a bad cable, usually meaning you have lost the shielding or ground connection somewhere.

On my old turntable I had one of the molded plastic connectors fail. I had to cut it off the wire and solder a new connector on the end.

Try wiggling the Signal Cables and see if it effects the hum, it if does, it means a cable or a connector has failed. Though it could be that the wire failed in the Tonearm/Cartridge. Check the Cartridge wiring very carefully and see if one of those wires has failed. The wire that connects to the cartridge is very thin, which doesn't leave much margin for error. I've also had these tiny wires fail and had to re-solder them.

When soldering the shielded cables, one thing that can commonly happens is that the shield melts down through the insulation of the center conductor, and over time can short that out. That is worth a close inspection.

Upon further inspection, it looks like the Black Wire is the Shielded Signal wire. Check the Yellow and Red wires where the shielding touches them and see if it looks like the shield has melted down through the center insulation. This is something that can be fine in the beginning but fail over time.

If the RCA connectors on the other end are removable, screw the shells off and check the internal wiring to make sure a wire hasn't broken or that a stray stand of wire is not now shorting the signal.

Steve/bluewizard
 
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