Repairing Run Away Speed Problem on Technics SL-5300 series Turntables

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-5350TT Pic 1.JPG

Remove the rubber mat and remove the platter by putting your fingers into the holes in the platter and pulling straight up.Mat Removed.JPG
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.
Platter removed.JPG
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.
TT bottom.JPG
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.

Inside bottom.JPG
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.

Motor plug and joints.JPG
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.

Screw arrow.JPG
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.
screws and center bracket.JPG
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.
Motor board out w joints.JPG
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.

Motor joints after soldering.JPG
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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For those repairing turntables that have the ability to stack records, the inside of the center bracket is below. The part that slides back and forth controls the movement of the spindle. It has to go back on so that the nub, which is near the top of the picture, is in the track of the main white gear. The round spindle, which is the black thing sticking up near the bottom of the picture, is connected to the white part that goes back and forth when the main gear rotates. This pulls and pushes on the bottom of the stacking spindle so that it performs properly. The black part goes into the center of the round hole in the middle of the motor assembly.

center bracket inside.JPG

If the lubricant has dried out so that this part is difficult to move this is a good time to clean out the old lube and install new lube.
Once you put this part back on, turn the turntable over and cycle the turntable by hand to make sure it doesn't bind. If it gets stiff or even just a little difficult to turn the platter, immediately stop turning the platter. You probably don't have the nub from the center part in the track of the big white gear. If you force it you will break off the nub. Turn the platter backwards and take the center bracket off and make sure the nub is in the track of the main white gear.
 
I suspect that the 5100 and 5200 series turntables use the same motor board but I haven't worked on any of them yet. It's good to know that your 5200 was similar.
 
It worked!! Thanks a million!
Now can anyone give any advice what the best way is to clean the body. Through the years there is some buildup of dirt. I am sure it can be removed, but how?
 
I successfully did this exact repair on a 5100 this week. :)

I got a decent closeup of the cracked joints:
Yfo1Lrj.jpg
 
It's better to remove the screws on the bottom and unplug the connector, then turn the unit over to remove the ones on the top so you can pull the motor assembly out without having it drop. if you have an SL-5100, 5200 or 5300 then you don't need to open the bottom, just remove the 3 screws as indicated, unplug the connector and pull the motor straight out.
 
I wonder if this or something similar might have worked on the Technics SL-7 I once had. I eventually gave up on that.
 
Certainly possible. The broken joints prevent the system from knowing how fast the turntable is spinning. My spun at about 175RPM according to an RPM app on my phone before I corrected the problem.
 
Hi
Thanks for the tip regarding soldering the 3 nodes, which helped on my Technichs SL5200 and the speeding like crazy.
But it only works when i am in manuel mode and adjust the speed there.
When changing to Quartz control it run a little too fast, any idea how this can be adjusted.
inside there is a possibility to adjust tracking and speed as well, but that still only working on the manuel adjust?

Anyone have any idea to get it woorking when running under quartz control?
Thanks in advance
Bent
 
Hi Jeffpaletz,

I just wanted to thank you for your ultra-detailed explanation about how to repair this issue. I´ve got a SL-5310 model and now it´s running like the 1st day.

Greetings from Qatar to all community!!

Jose
 
I had this issue on a technics sl-1200 mk1 (same motor as sp10 mk1). The issue was inside the motor unit somewhere, because swapping the motor assembly fixed it. I've been wondering if it'd be possible to repair it so I have a spare. Or if anyone wants it, PM me.
 
Technics 5350 platter.jpg Technics 5350 spindle.jpg No, it does not need to be removed. The platter separates from the brass piece that it sits on. Do not remove the c clip. You will have to pull up on the platter to get it to pop off. Use the two holes in the platter and pull up hard to pop it off.
 
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Just wanted to say thank you for this repair thread! I bought a Technics SL-5300 as my first table a few years ago, and a few days into ownership, it developed runaway, wrecking my brand new cartridge and my happiness in the process. Back then I had tried to find a solution, but trying to clean parts with deoxit, or searching for replacement parts that were too pricey to justify didn't work for me, and thus I tossed it in my garage and forgot about it. Today I saw it and decided to give repairing it another shot, and happened upon this thread. After about 15 minutes I have a perfectly functioning turntable again! Now to find a new cart for it. ;)
 
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