Only one channel audio working TD150

[gareth_morgan_1986]

Hi everyone,

Relatively new turntable user. I have my Thorens plugged into a phono preamp which then goes into amp.

All sounded great until I recently went to play a record, and I only had one channel of sound.

Have checked all plugs are in correct.

Even tested diff aux lead with iPhone, which works both channels.

I've come to the conclusion that it may be the headshell wiring? As if I touch the needle only one speaker produces sound.

Can anyone shed light on this? And if so, how on earth do I fix the wiring of the head shell?!

Any help would be appreciated.

[markcass]

Hi

As a quick check, try removing the headshell from the arm and cleaning the contacts at the connection. Removing the headshell will also make it much easier to examine the leads.

If you then disconnect the leads from the cartridge, and have access to a multimeter, you will be able to check for continuity in the arm wiring (both within the headshell and from the front of the arm to the plugs).

Good continuity all through would narrow the problem down to the cartridge.

HTH

Mark

[gareth_morgan_1986]

Hi Mark,

Thanks for responding.

I may have done this in reverse to your method, as I dont have a multi-meter I can use.

So I removed the headshell. All the wires were secure to the cartridge, however, slightly oxidised, and not new. (If I clean the pins/wires etc, what would you recommend to clean with?)

I have a spare cartridge that came with the TT (also, not new) so I swapped the cartridges. But no change. Still, only the right channel has audio.

Not sure what to do. I wish there was a Thorens service shop in every town!

[RED_One]

I'd swap phono leads around on amp - if the problem swaps its the deck if not the amp is culprit

Other than check the headshell leads & wiring of the cart I'd renew the phono plugs on the deck - these often get broken wires etc

[gareth_morgan_1986]

Ok, TOTAL newbie question here ( please forgive):

If its the phono plugs and they need renewing. I might attempt tomorrow.

Is this a fairly simple procedure? And is there a step by step online somewhere?

I don't even know how to get inside the tt?!

[RED_One]

these would be the phono plugs on the end of the arm leads & on a Thorens would be grey (at least on a TD160)
no need to open the TT up unless you are renewing the leads as well

I had mine from maplin 1 red + 1 white - & had them soldered by a TV repair man cost £5.00 which I forced him to take

[Alec124c41]

Or to rephrase that, the RCA plugs on the cable that plugs into the pre-amp. The wires often break just behind them, because they are most likely to get bent there.
A digital multimeter can be had quite cheaply, and will take the guesswork out of this kind of problem. You can spend weeks doing all the wrong repairs, and spend more money than a meter will cost.
A small spray can of contact/control cleaner is indispensable. Use it (sparingly) on cartridge connectors, headshell contacts, RCA plugs, etc.

Cheers,
Alec

[gareth_morgan_1986]

Ok, thanks guys, understood.

I'm going to get a multi-meter today, and some contact cleaner.

I think this may have something to do with it :



The original cable wasn't an RCA plug, it is a pin plug. Which I found an adapter for.

Do you think its an idea to update the pin plug for RCA?

[markcass]

Hi

It would be better to have RCA plugs soldered directly to the grey cable, and get rid of the DIN plug/ adapter in the circuit. In the short term, try disconnecting and reconnecting the plug and adapter, as this should clear any corrosion.

If that doesn't work, it could be that a wire has simply become disconnected inside the DIN plug on the end of the phono lead from the Thorens. However, as curing that would mean opening the plug and soldering the wire back anyway, you might as well go the whole hog and replace it with two phono plugs.

Mark

[gareth_morgan_1986]

Thanks for that Mark (and everyone else),

I've just bought a multimeter, cheapest I could find!

http://www.hisgadget.com/blog/files/201 ... 30B-01.jpg

Is there a tutorial on how to test continuity on audio? Setting to use? Results to expect? etc

- Mark,
This is what I meant by opening the TT and replacing the whole lead with a brand new phono. However, thats a bit out of my capabilities. So I think exchanging the DIN for the phono plug is best.

I will do that, if this continuity test proves otherwise.

[gareth_morgan_1986]

Quick reply here, see if I've done this right.

I touched each wire separately (blue,white,red,green) with both the red and black test leads.

The multimeter was set on Ohms, 2000k.

Each wire had the following results:

Red: 500 - 1500
White: 500 -1500
Green: 500 - 1500
Blue: 500 -1500



I guess this means that I have continuity throughout the turntable and this is a phono issue?

[markcass]

Hi

What I think you need to do is touch each headshell connection in turn with one probe, and the corresponding pin on the phono plugs on your adapter with the other probe. Then try the pins inside the DIN plug attached to the phono lead itself. The white headshell lead will go to the centre pin of the white phono plug, the blue headshell lead to the outer connector; it's red and green, respectively, for the other channel.

I've just tested a known-good phono-to-phono lead with my own cheap multimeter and got a reading of about 0 on the 2000k setting. This is what you'd expect, as there is almost no resistance if the connection is sound. Some meters have a continuity test mode, which beeps if there is a good connection.

HTH

Mark

[gareth_morgan_1986]

Hi all,

Thanks for everyones thoughts on this. I did have a look at it myself on Sunday, but admitted defeat pretty early on (I'm just not technical enough!) and got a pro to look at it for me.

Seemed for the best too, I got the original phono cable removed and replaced with a shiny new one, and the headshell wiring all replaced, as it seemed all the soldering was from the '70s looking brittle and brown. All in 2 days, and a humble cost too.

Celebrating tonight with plenty of Simon & Garfunkel!

Thanks again :]