# Old Sony Turntable problem



## Rostafar (Jan 30, 2014)

Hi. I have an old sony ps-lx40p turntable, unfortunately, i no longer have the rest of the deck. The turntable has an aux lead and for power it has a 3-pin female connector. One wire is negative, one positive and the middle is not connected. From reading other forums i found i could try connecting this to a 12v 500ma adapter. However once trying this and plugging it in, nothing happened and the turntable won't spin. Does anybody have any suggestions of how i can get this powered and working as i really hope to get it working, despite it's age.


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## cwwozniak (Nov 29, 2005)

Hi Rostafar, and welcome to TSG.

Since you did not specifically mention doing certain things, and not knowing your skill level, I may be asking some questions that may seem obvious to you.

1) Did you make sure that you had the polarity correct when you connected the 12 VDC supply?

2) Did your reading confirm that a 500 mA supply would have a high enough current rating to operate the turntable?

3) Did you move the tonearm to a position over the turntable?

4) Did you check if the drive belt was in place and not slipping?

FWiW, I found a service manual for your turntable:
http://freeservicemanuals.info/en/servicemanuals/viewmanual/Sony/PSLX40/PSLX40P/PSLX43P/PSLX44P/


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## Rostafar (Jan 30, 2014)

Thanks chuck, yeah im a bit of a beginner when it comes to dealing with electrical problems. 

1) Im not sure about how to check the polarity so if you could help with that, it would be great

2) Yes i checked and 500ma was the minimum ampage required

3) Yes i read that sometimes moving the tonearm over works, but it didn't for me

4)Yes the drive belt is in place, however there is no rotation

And that's great thanks i didnt have the manual


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## cwwozniak (Nov 29, 2005)

Rostafar said:


> 1) Im not sure about how to check the polarity so if you could help with that, it would be great


The service manual in my earlier link includes a drawing that shows the correct polarity for connecting the 12 VDC. The turntable power cable should be black with a white stripe on one edge. The wire with the white strip connects to the negative side of the power supply and the wire at the other edge of the cable connects to the positive side of the power supply.

If you hooked it up the 12VDC supply backwards there is a very good possibility that you damaged an electrolytic capacitor on the motor control board, but not the AN6652 motor controller. From what I can read about that part, at least one manufacturer makes them with reverse voltage protection.

Do you have any kind of a voltmeter or multimeter you can use to isolate the cause of the failure?

Also, you mention the turntable has an "Aux" lead. From what I can tell from the service manual, the outputs are directly from the pickup cartridge. You would need to use an amplifier with a phono cartridge input or use a small phono pre-amp to convert the cartridge outputs to line level outputs.


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## Rostafar (Jan 30, 2014)

I managed to get the positive and negative wires connected the right way around so hopefully there should be no damage to the electrolytic capacitor. However the adapter that i connected it to is positive to centre polarity. Would this cause any problems trying to power the turntable? 

And no unfortunately i have no voltmeter or multimeter. Would it be best to buy one to try and figure out the failure? 

Okay thanks, i am thinking of buying a phono pre-amp, but it all depends whether I can power the turntable or not.


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## cwwozniak (Nov 29, 2005)

How are you connecting from the plug on the output of your power supply to the 3 three contact connector on the turntable?


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## Rostafar (Jan 30, 2014)

I cut the wires and used block connectors to join them. I found when openeing the bottom of the turntable that the middle wire from the 3 pin connector was indeed unconnected so i just joined the negative wire to the negative wire from adapter using block connector and the same with the positive, leaving the middle wire disconnected.


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## Rostafar (Jan 30, 2014)

From the diagram in the service manual i think it is negative to centre polarity. Does this mean I should get an adapter that has the same polarity as the turntable?


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## cwwozniak (Nov 29, 2005)

If you cut the connectors off the power adapter and turntable cords and used a terminal block to connect the stripped ends, it should not matter which wire on the power adapter went to the center pin of the original plug. You just need to make sure that the positive wire coming out of the adapter went to the positive wire to the turntable.

A fairly inexpensive analog or digital multimeter would be a great aid in troubleshooting your problem. You could use it to check:

1) Make sure the DC voltage going into the terminal blocks is a nominal 12 VDC. An overload or short in the turntable could cause the power adapter voltage to drop or cut out, as a safety measure.

2) The DC voltage going into the motor control printed circuit board is 12 VDC. This will test if the switches between the power input and the printed circuit board are malfunctioning.

3) If any DC voltage is being applied to the motor. This would be less than 12 VDC, but not zero or a very low voltage.

One check you could do without a volt meter would be to see, with no power applied, if the motor freely rotates when you move the turntable by hand or try to turn the motor shaft with your fingers.


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## Rostafar (Jan 30, 2014)

Yes thankyou, I might buy a voltmeter then and find the problem easier.

Okay I did that check and found that the motor of the turntable turned freely by hand with no power. What does this mean?


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## cwwozniak (Nov 29, 2005)

Just wanted to make sure that there weren't any mechanical issues that might be preventing the turntable from turning. A worn bearing on the motor could cause binding of the shaft.


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