The arm will automatically return without playing the record

Yes. you need to set the travel on your arm. I don't know your specific model but they are all the same concept. On the back by the pivot point there should be a small screw that you can adjust the travel before it returns.

The top arm that swings over the spindle will control the automatic return. Leave the unit off. Swing the overhead holding top arm over and manually load a record. Now switch the top arm over the niddle spindle. Make sure that the switch is set for 7", 10" or 12" (45, 78, or 33). Manually place the tonearm at the start of the record and flip switch to 'play' (not reject or auto). It should play the whole record and automatically eject at the end and then shut off. Leave the arm swung over the middle after you loaded the record. Good luck. Let me know if you have any more questions.

Hi, if it's a second hand device. there must be something wrong with the arm at it's moving axe. if something (dust or broken support) is blocking it, it will return automatically to its rest position to avoid any damage to the fragile and sensible "head"

Not meaning to resurrect an old thread, but I had the same issue and found the culprits after a few hours of fiddling around. The autoplay was dropping the needle close to the middle of the record and then picking it up again and returning indefinitely. I'll leave this here for anyone else who has this issue.

The auto drop adjustment is not what you want to be messing with, but you need to take the bottom main assembly out and focus on the parts in the attached pictures.



These two parts are screwed onto the largest/main cog on the main assembly. Mine were gummed together with old grease. They are easily removed and cleaned and relubricated.





The two shafts on the PU assembly are meant to move independently - mine were again stuck together with old grease. I worked them loose and applied some new lubricant.

After cleaning these parts it worked perfectly again!

most turntables actually only dampen during automatic play and return (eject) not when manually manipulating the needle. Better turntables will have a counterweight at the back of the arm behind the pivot point, but that is to decrease wear on the vinyl and increase needle life and audio fidelity in the higher end.
Some turntables have a lifter arm that is dampened, but if your player doesn't have such a mechanism, or if it has one and you choose to manually manipulate the needle without it's usage, there is no dampening.
The fix unfortunately is to buy a turntable with a dampened lifter arm, and to use the arm when lifting and lowering the needle.

I suppose the only way to do it would be to stop it functioning completely. The only way would be to dissasemble the auto function. What you would need to do is work out which parts are essential for the turntable operation and which only activate the return. So you need to whatch the mechanism working. You will need to remove the base and look at from underneath, just like going underneath a car!
I can't say for certain if you can do it, only you will be able to determine it can be removed without affecting the operation of the entire turntable.

There should be some kind of screw on the arm to adjust it. You might have to experiment, or get a service manual. When adjusting, try doing it without the platter powered, by hand movement only.

I have a possible solution to your problem, but will need to talk you thru it. You can register at AudioKarma.com and send a private message to Ghazzer.

http://www.vinylengine.com/library/pioneer/pl-570.shtml
on page 8 of the above service manual for your model it shows 4 electrical switches that tell the computer what 'state' the mechanism is in at any given time. Either one or more of the switches are intermittant or the mechanism has dried up grease that is slowing down the operation and basically gumming up the works. the old grease would have to be removed and replaced when it is causing binding. The switch just to the right of where is says "microswitch ksf-023" is an 'open air' type and so would be the most likely suspect. it simply needs to be cleaned with a super fine file designed only for cleaning switch contacts. THIS SERVICE SHOULD ONLY BE PERFORMED BY QUALIFIED PERSONNEL ONLY!!!!!

Are the record size tabs sticking up through the turntable platter cover? They sense the size of the record being played and adjust the run out distance for either 45 or 33 rpm records.