jeffpaletz
AK Subscriber
Sometimes the Technics SL-5000 series turntables will spin at a very high speed due to cracked solder joints on the motor board. This occurs because the speed control circuit is not receiving speed information from the motor board. If you know how to solder and are handy, this is an easy repair. I've performed this repair on a few SL-5350 models. The problem is often intermittent. I've measured the turntable speed while this is occurring using the RPM app on my Iphone and it showed that the turntable was spinning at 175 RPM. If you try to measure the speed on your turntable when this is happening be sure your phone is centered on the platter so it doesn't fly off.
This repair is not intended to solve the problem of the turntable intermittently running a little slow or fast which can be caused by the speed change switch, quartz lock switch or the speed adjustment control being dirty and needing to be cleaned with contact cleaner.
I will explain how to do this repair. Remove the center spindle, head shell and counter weight before starting to work on this.
Technics SL-5350
Remove the rubber mat and remove the platter by putting your fingers into the holes in the platter and pulling straight up.
In the center of the picture is the coil part of the motor. The bottom of the platter has the other part of the motor attached to it which is the magnet.
Put a soft towel on your work surface that you will place the turntable on.
Lock the arm down and turn the turntable over on its top and remove the seven screws holding the bottom on.
The picture below shows the the inside of the turntable. In the center of the picture is the motor board. It has a wide white plug attached to it.
The area that you need to solder is just under the the area covered by the mechanism plate. The three solder joints that sometimes crack are the ones in a triangle shape above the row of pins that the white plug plugs into. If you have a pencil style soldering iron you can get to those solder joints and add more solder which will repair the cracks and fix the problem. Once fixed your turntable will work reliably.
If you can't get to the solder joints it's possible to remove this part of the motor from the turntable. Refer to the picture above with the turntable right side up showing the motor after the platter has been removed. You will see 6 screws. There are 3 screws that need to be removed from the top of the motor and three under the turntable that need to be removed. From the top of the motor remove the three screws that have an arrow pointing to them. Do not remove the other three screws that do not have an arrow pointing to them.
Turn over the turntable so you can access the bottom. Unplug the wide white plug from the motor board. Remove the three screws holding the center bracket. The motor board will drop down to the towel. Take it out so you can work on it. If your turntable is a record stacking model be careful with the mechanism inside the center bracket. It will need to go back on the same way you took if off.
The motor board is below after being removed. Note the three solder joints in a triangular shape. These are the three solder joints that need to be repaired by adding more solder to them and re-flowing the solder.
These solder joints are not cracked yet but you can see the center of each joint has a dimple which over time might crack. They can crack during shipping or if the platter is stuck on to the base and is pulled off with great force.
See the repaired solder joints below.
For those repairing turntables that have the ability to stack records, I will show in the follow up post below the inside of the center bracket. The part that slides back and forth controls the movement of the spindle. It has to go back on so that the nub is in the track of the main white gear. The round spindle also is attached to the white part that goes back and forth when the main gear rotates. The pulls and pushes on the bottom of the stacking spindle so that it performs properly.
I will monitor this thread and try to answer any questions posted here. I've seen other threads talking about this problem and hope this helps others here fix their turntables if this is the problem.
This repair is not intended to solve the problem of the turntable intermittently running a little slow or fast which can be caused by the speed change switch, quartz lock switch or the speed adjustment control being dirty and needing to be cleaned with contact cleaner.
I will explain how to do this repair. Remove the center spindle, head shell and counter weight before starting to work on this.
Technics SL-5350
Remove the rubber mat and remove the platter by putting your fingers into the holes in the platter and pulling straight up.
In the center of the picture is the coil part of the motor. The bottom of the platter has the other part of the motor attached to it which is the magnet.
Put a soft towel on your work surface that you will place the turntable on.
Lock the arm down and turn the turntable over on its top and remove the seven screws holding the bottom on.
The picture below shows the the inside of the turntable. In the center of the picture is the motor board. It has a wide white plug attached to it.
The area that you need to solder is just under the the area covered by the mechanism plate. The three solder joints that sometimes crack are the ones in a triangle shape above the row of pins that the white plug plugs into. If you have a pencil style soldering iron you can get to those solder joints and add more solder which will repair the cracks and fix the problem. Once fixed your turntable will work reliably.
If you can't get to the solder joints it's possible to remove this part of the motor from the turntable. Refer to the picture above with the turntable right side up showing the motor after the platter has been removed. You will see 6 screws. There are 3 screws that need to be removed from the top of the motor and three under the turntable that need to be removed. From the top of the motor remove the three screws that have an arrow pointing to them. Do not remove the other three screws that do not have an arrow pointing to them.
Turn over the turntable so you can access the bottom. Unplug the wide white plug from the motor board. Remove the three screws holding the center bracket. The motor board will drop down to the towel. Take it out so you can work on it. If your turntable is a record stacking model be careful with the mechanism inside the center bracket. It will need to go back on the same way you took if off.
The motor board is below after being removed. Note the three solder joints in a triangular shape. These are the three solder joints that need to be repaired by adding more solder to them and re-flowing the solder.
These solder joints are not cracked yet but you can see the center of each joint has a dimple which over time might crack. They can crack during shipping or if the platter is stuck on to the base and is pulled off with great force.
See the repaired solder joints below.
For those repairing turntables that have the ability to stack records, I will show in the follow up post below the inside of the center bracket. The part that slides back and forth controls the movement of the spindle. It has to go back on so that the nub is in the track of the main white gear. The round spindle also is attached to the white part that goes back and forth when the main gear rotates. The pulls and pushes on the bottom of the stacking spindle so that it performs properly.
I will monitor this thread and try to answer any questions posted here. I've seen other threads talking about this problem and hope this helps others here fix their turntables if this is the problem.
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