Auto-Return Issue

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Vinylcrate
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Auto-Return Issue

Post by Vinylcrate » 06 Mar 2017 18:14

Hi all,

I recently received a Technics SL-220 turntable from a father of a friend of mine. It's been sitting in his basement for many years and was in need of some new parts. I found suitable replacements for the cartridge and belt online. However, when I went to go start it up I realized the arm is stuck in an auto-return loop. When the needle is positioned over the record, the platter starts spinning, then returns the arm to the holder.

So far, I've tried the following, based on what I could find:

1. Rotating the platter counterclockwise to reset the auto return mechanism - Failed

2. Opening the bottom of the turntable and lubing the main gear as well as some other movable parts to the auto-return mechanism closer to the tone arm with lithium grease. Once lubricated, I tried to actuate the mechanism by hand. - Failed

I'm wary of taking the whole turntable apart to get at the auto-return mechanism, even with the service manual on hand, as it's under a metal plate and interlocks with so many other parts of the turntable. Would it be best to take everything apart, clean it, and lubricate the turntable? Or do you think a hardware issue may be the cause?

musicmn
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Re: Auto-Return Issue

Post by musicmn » 07 Mar 2017 00:58

Hi, you are on the right track with the old grease being the problem. I have serviced quite a few of these deck recently and I still own the SL 220 I bought new in 1979. These decks are well worth the time and effort to clean and set up. I have included a couple of pictures of the problem areas with these decks. But really the entire mechanism should be removed, cleaned and fresh grease applied as they are reassembled. The cueing mechanism should also be disassembled, the old silicon damping fluid cleaned out and new 300,000wt silicon damping fluid put back in. This will make the tonearm drop nice and slow. You can use alcohol and rags to clean the old grease out. And I like to use Super Lube to lubricate the mechanism. Super Lube is a silicon based grease available at most good hard ware stores. They sell it in small tubes that are great for doing just one mechanism. The 300,000 wt silicon damping fluid can be bought on line. Again only a small amount is needed. The pitch controls should also be cleaned with good deoxit spray (contact cleaner). Both the pitch pots and the variable resistors. You can find videos on You tube that show just how this is done so make sure you check them out. I hope these pictures help.
Attachments
Technics SL220 turntable 014 (Copy).JPG
The red arrows show areas where the old grease needs to be removed. On the levers in the lower left hand corner. These need to be removed so the bottom lever can be removed and cleaned. Again super lube works great in these.
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Technics sl220 turntable 006 (Copy).JPG
You will find the VR's under this board. Remove the screw and flip the board over to clean them.
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Technics sl220 turntable 002 (Copy).JPG
Variable resistors (VR's for short) these need to cleaned with deoxit spray, then use a small screw driver to rotate them gently back and forth a couple of times and repeat. Then set then to as close to there original position possible. Again there are a lot of posts explaining how to adjust the speed of the platter using these VR's. Clean up all over spray with a rag or paper towel.
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Technics sl220 turntable 009 (Copy).JPG
Pitch pots, these are the ones that you use to adjust the speed of the platter from the outside of the deck. Spray some deoxit into each one. Let it sit for a while then rotate the stem of each one a bunch of times back and forth. Repeat these steps until the stems turn freely. This will help to stabilize the platter speed and make the controls not so sensitive to the touch.
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Technics SL220 turntable 011 (Copy).JPG
This is the spindle, notice the old black graphite grease. This old grease needs to be removed and I use Super Lube in it's place.
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analogaudio
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Re: Auto-Return Issue

Post by analogaudio » 07 Mar 2017 00:58

welcome to VE

I used to have one, I liked it and it served me well. The auto-mechanism on mine also needed a little help after some years in storage. I don't recall precisely the problem but I do recall working with the unit on the bench upside down with the bottom cover off and the platter off and studying the mechanism while I moved the arm and turned the spindle by hand to simulate a playing cycle. This may work for you, it requires patience :-)
Dismantling (especially old) things sometimes causes accidental damage, I don't recommend dismantling everything at the beginning, perhaps it would be wise to save that until the operation is understood and the problem is pin-pointed.

Vinylcrate
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Re: Auto-Return Issue

Post by Vinylcrate » 07 Mar 2017 17:53

Hello musicmn and analogaudio,

Thanks for your replies. I think I'll try to disassemble what was pointed out in the musicmn's pictures. I'm going to buy the suggested lubricants and cleaners before going ahead with the disassembly.

I had seen posts that mentioned disassembly and lubrication on other forums, but none as specific as here. It's really helpful!

Hopefully, I'll get to the repair this weekend. I'll keep you updated.

Thanks for all of the help

Vinylcrate
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Re: Auto-Return Issue

Post by Vinylcrate » 10 Jun 2017 22:02

So I was finally able to buy all of the fluids and greases. I disassembled the turntable and cleaned off the old grease. It was all pretty dried out. Luckily I was able to redo it all and the mechanism seems to move much easier now.

However, I still can't seem to get the turntable to stop returning the arm and shutting down. Might I be missing a piece or could something be broken that would tell the turntable to stop shutting down?

I'd really like to keep the auto-off feature, but I can't seem to get it to work.

Csibesz1967
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Re: Auto-Return Issue

Post by Csibesz1967 » 17 Aug 2019 05:13

@musicmn. I also am doing a thorough disassembly of my SL 220 thanks to your excellent and detailed post. You mentioned replacing the fluid for the tone arm lift. Could you post pics on that. I'm looking at mine and it has a circlip holding a spring at the bottom. Is that what I take apart to put the fluid in or is the fluid just spread on to the shaft that the spring is on. Would like a little more clarity on how to lube the tone arm lift. Thanks.

musicmn
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Re: Auto-Return Issue

Post by musicmn » 17 Aug 2019 22:04

Hi, replacing the old silicone damping fluid is the most difficult thing to do on this turntable. It entails removing the tonearm so the plate that the cue piston is attached to can be removed and the cue piston pulled out. I have included the only pictures I have of this area. The top picture is showing the spring plate that is attached to the tonearm. The tonearm wires must be desoldered from the small circuit board that they are attached to and the Black cue elevator that's under the tonearm needs to be removed. Then the two screws in the picture with the yellow arrows need to be taken out. But be very careful these screws are usually stuck and you may need to drill them out to remove them. But first try using a very good Philips head screw driver to loosen them before you drill them out. The anti skate mechanism must also be removed so you lift out the spring plate. Becareful with the anti skate spring don't bend it or pull it to hard. Once the spring plate is out then I believe you will find one or two screws that hold the plate down that the cue piston is attached to and these screws also hold the tonearm onto the base of the turntable. Now with all that done the cue piston and plate in my second picture can be worked on. Remove the C clip and then the spring and pull the piston out of the cylinder. Note which way the piston is install into the plate. Clean the piston off using alcohol and rags then clean inside the cylinder the piston fits into. Also clean off any old grease from the piston and the anti skate parts. You will find that the piston has a couple of grooves in it that is where the damping fluid is placed. Put a small amount of the damping fluid in the grooves and install the piston and work it up and down and spin it a couple of times to evenly spread it out inside the cylinder. How much to use is very hard to say what I tell people to do is to assemble the cue mechanism and install the tonearm but do not solder the wires yet. Once you have the cue mechanism, anti skate parts and the tonearm installed flip the turntable over. Then install the headshell with the cartridge minus the stylus for not. Then install the counter weight and the tracking force. Use the cue lever to check the drop rate of the tonearm if it's still to fast then you will need to disassemble everything again and add more damping fluid to the piston. If it's very very slow again you will need to disassemble it and clean off the fluid and add a smaller amount to the piston. Like I said this is a very detailed service and it is quite complex but it can be done. Take as many pictures of this area as you need so when you go to install everything you have a good reference as to how it all fits. I don't have any pictures of the parts located under the cue piston plate so take some good pictures of that area before you lift those parts out of the base. You will find a lot of old grease under that cue plate that needs to be cleaned out and replaced with fresh grease. When all of this done and the rest of the mechanism is cleaned and lubricated you will have a very good working turntable that should give you many years of service. I hope this helps.
Attachments
Technics SL220 turntable 004 (Copy).JPG
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014 (Copy).JPG
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Csibesz1967
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Re: Auto-Return Issue

Post by Csibesz1967 » 18 Aug 2019 08:45

@musicmn. Thank you for your prompt response. I have this turntable torn down completely. I've already completely disassembled the whole return unit , cleaned and reassembled with the Super lube you recommended. I also disassembled the cue and stop sliders and also lubed them. The reason for the complete tear down is that this unit had heavy dust in every corner. The cue and stop sliders were so full of dust that they didn't even move. Now after cleaning and lubing they're like brand new. Now all that is left is to clean out the tone arm lift and she's ready to go back together. Again I really appreciate your help.And yes before I disassembled this turntable I took a lot of pictures especially of the return mechanism. Made for a smooth reassembly.

Csibesz1967
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Re: Auto-Return Issue

Post by Csibesz1967 » 22 Aug 2019 23:08

@musicmn. I am reassembling my turntable. I took a picture of the circuit board that the tone arm wires are soldered to but when I took the picture I still had the factory black tape covering where each wire solders to. I looked in the service manual but there is no schematic for the tone arm wires only everything else. You wouldn't happen to have a picture of the order the tone arm wires are soldered to that board? Thanks

musicmn
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Re: Auto-Return Issue

Post by musicmn » 23 Aug 2019 01:45

Hi Csibesz1967, I don't have a picture of that exact board but I do have a picture of a board from and SLd2 I hope it helps. All you need to remember is that the red (+) and green (-) wires are the right channel and the white (+) and blue (-) wires are the left channel and the black wires are ground.
Attachments
Technics SL D2 turntable 016 (Copy).JPG
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Csibesz1967
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Re: Auto-Return Issue

Post by Csibesz1967 » 23 Aug 2019 03:06

Thank you immensely @musicmn. You are a saviour. The only picture I found on the net was blurry when I magnified it. Again Thank You

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Re: Auto-Return Issue

Post by Csibesz1967 » 05 Sep 2019 00:13

@musicmn.
Thanks again for the help. The SL-220 is running like brand new and sounds awesome. This turntable has been in this family since new back in 1978. I remember as a kid that I wasn't even allowed to touch it back then. Now 40 years later I'm touching it and actually restored it back to good condition.

musicmn
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Re: Auto-Return Issue

Post by musicmn » 07 Sep 2019 19:50

Your very welcome I'm glad I was able to help. :D

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Re: Auto-Return Issue

Post by lenjack » 07 Sep 2019 20:03

This is a perfect example of the amazing things this forum can do.

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