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PS LX4

Posted: 19 May 2019 11:30
by Dangermouse67
Hi guys,
Newbie here...in need of help.
I have a Sony PSLX4 which i have owned from new. It has spent the last 15-20 years unused in my loft.
I got it out last week and hooked it up to my Sony XO7 tuner amp (also owned from new). Everything is working fine except the turntable is running a bit slow on both 45 and 33.
I have the service manual, contact cleaner and a multimeter.
I consider myself practical but electronics is all new to me ... where do i start please?
Would love to get it running again as it is quite sentimental to me.
Thanks in advance.

Re: PS LX4

Posted: 19 May 2019 12:15
by bernard1
What speeds did you measure ?
Motor could eventually need some lubrication after long period unusing the turntable.

Re: PS LX4

Posted: 19 May 2019 14:44
by Dangermouse67
Hi,
Have only used an app on my phone (after hearing the difference when playing a LP) and it measured about 4% slow.

Re: PS LX4

Posted: 20 May 2019 02:33
by musicmn
Hi dangermouse67, I have only worked on a pslx2 but from what I can see in the service manual for the pslx4 the circuit board looks almost the same. On page 11 of the service manual it explains how to set the speed for both 33.3 and 45.0. It says you need a scope to do this but a strobe mat or your app should get you right in the ball park. I've included a couple of pictures of the circuit board from the PSLX2 and show where the Variable resistors are located that are used to adjust the platter speed. I'm also showing how the motor can be pulled apart so the old oil can be cleaned out and new oil put back in. If you have Direct Drive motor oil that works best if not you can use sewing machine oil. Put a couple of drops into the brass bore and one or two drops of oil on the motor shaft. Then assemble the motor and push down until the motor is seated in the housing. It must not feel like it is bouncing when you rotate it must be seated firmly in the housing. When you push down on the motor while you assemble it you should be able to hear the air escaping from the housing. As far as the variable resistors go, spray each one with deoxit and let them soak a while. Then gently rotate them back and forth a couple of times using a small screw driver and set them back to there original position or as close as possible. If you have a can of compressed air blow off any excess deoxit and wipe it off the board as best as you can. Once you have the motor back in the the turntable. Flip the turntable over install the platter and set the base on some books or cans. Just get the base high enough so you can reach under it with a small screw driver to adjust the variable resistors while the platter is spinning. You can use your app or you can download a strobe pattern from the tools section on this site to use to set the platter speed. Once this is done you can put the bottom on and you should be all set. I hope this helps

PS, when my kids were small we use to watch danger mouse I thought it was a great cartoon. :D

Re: PS LX4

Posted: 20 May 2019 08:00
by Dangermouse67
Thankyou so much for all that info. Will read and digest tonight after work. Thanks again.
DM. :-)