Another Pioneer PL 50

[calman46]

So, this PL50 basically works, auto return most of the time. I worked on it 20 years ago but didn't know enough and wasn't happy with the outcome. It's time to look at it again. First off, the damping fluid I put in as leaked and was up in the auto return mech. I disassembled it and cleaned it good. Now for the lube part of the auto return mech. No lube on the Stopper #28 it stays clean and dry. I'm thinking on some super lube on the shaft of #66 and under #14 . #65 #26, #9 are Teflon washers so no lube. What do you think? There is very little contact surface at #16. I need to make the rotor cap #68 leak proof: I'm going to use 300k cst. for damping fluid. The cam lever #52 has been notched out on this PL50 which I think makes the Stopper#28 swing out further to get bumped by the platter pin, more on this later. Any thoughts or suggestions?

 

[calman46]

Its all aback together and it works the 300K cst damping fluid appears to be a good choice. I did use the original rubber gasket with some tube gasket maker from an auto parts store on both sides of it. With the TT upside down, I stuck the original gasket to mech plate with the gasket maker. I needed both hands to put the roto cap on with damping fluid in it, so with TT up righted and over a mirror the task was completed, with ease surprisingly. Now about the "clunk" when the TT shuts off. The TT is propped up with the bottom plate off, so that makes the clunk louder. I noticed with the platter off and trip the return mech with my finger the clunk is reduced to a click. I did replace some hardened rubber bumpers and now looking for more pinch points. I added some damping weight to the bottom plate and rubber coded the springs. Someone's else's " previous fix" of notching of the cam lever doesn't appear to do anything.

 

[calman46]

All done and back together . The return works nice and smooth as not as clunky. New needle for the original PC-35 cartridge. Howards feed a finish may the finish pop. It sounds good through my SA 9500; I like the extra weight on the base. Disabling the auto return is something to consider if I was going to use the TT on regular basis. Just remove #28 the stopper .

 

[calman46]

Another Pioneer PL 50 has found its way to me. It was somewhat neglected and worked on before ,as most of the screws where loose. But it's coming along good, so far. The non-working auto return was due to part #22 being bowed inward right after the tension screw #21 (not to be confused with the 90-degree bend for the notch on the return plate). I had to bend the bow a little in reverse of it, as just straightening it didn't give enough holding force. I notice that when the tonearm is at rest and the function lever is at Cut/Off, PN#22 (Return guide plate holder) is engaged. So, moving the tonearm in cut/off disengages #22 from guide plate, so maybe this action weakens or if abrupt enough bows #22. It seems like a lot of these PL50's suffer from non-working auto return. Tightening #21 lessens the hold force and could cause the bowing on #22. I just snugged it up the #22. Leaked out damping fluid is another common issue. Thanks to Try1256 for the early post.

 

[kwingylee]

Hi calman46, I know this is an old thread but how did you apply the 300K CST damping fluid? Do you have to take the entire assembly apart? I don't want to do that because to be frank, I don't think I can put it back together correctly.... can I just drop the fluid in??

 

[calman46]

Look at the second picture in post #2. and read the post. You have to remove the case bottom and the small cap like cup . Clean it all out discard old hard gasket. , you most likely will need a tube of gasket maker also. Prop up TT so you can access the underneath with the TT upright. I used a mirror so I could see. I put the gasket maker on the cap/cup filled it with the damping fluid, push the cups screws through so the gasket maker held them , then looking in the mirror I installed it back in. I did a test run with no gasket maker or fluid'

 

[kwingylee]

Look at the second picture in post #2. and read the post. You have to remove the case bottom and the small cap like cup . Clean it all out discard old hard gasket. , you most likely will need a tube of gasket maker also. Prop up TT so you can access the underneath with the TT upright. I used a mirror so I could see. I put the gasket maker on the cap/cup filled it with the damping fluid, push the cups screws through so the gasket maker held them , then looking in the mirror I installed it back in. I did a test run with no gasket maker or fluid'

Thanks I removed the cap held by the small screws. There is clear jell underneath that. Are you suggesting cleaning all that out, remove the black gasket and use gasket maker to redo the entire thing? You must be a master at this, because I don't think I have the skills to put it all back together..... can I just use a syringe to apply the new fluid once I clean out the old grease?

 

[calman46]

Is the gel thick? did the arm struggle to move ? You will have to turn the cap upside down to put back in ,the new fluid will run out , that's I worked from underneath using a mirror .

 

[kwingylee]

The gel looks and feels like gel.. the arm moves freely. Are you saying I should remove the "gel" and replace it with the 300K cst fluid? I am buying a kit from Amazon to apply the new oil without having to take everything apart...

 

[calman46]

The fluid in mine was thick and sticky and the arm moved slowly , plus some had leak out at some point . You don't have to take the TT apert to "oil" it , you just need to use something that won't run out like Super Lube. You need to use the 300K cst fluid for the arm damping. If your spindle bottoming out you need a new thrush bearing , you can get one on ebay .