BSR McDonald with a squeaky idler wheel

[littleguy]

Hey guys, I'm kinda new around here, but I've been poking around for a while and figured I'd step up to the plate with a question.

I've got an old full-auto idler wheel BSR turntable, and I've taken it apart (to the extent that my knowledge permits) and re built it after a thorough cleaning and re grease/lube-ing. (It was previously non-functional, but now spins fantastically).

When the motor is switched off, the idler wheel disengages from the platter and motor spindle so the platter spins freely, and makes minimal noise. I know no noise is ideal, but this thing is ancient, and was recently broken, so I'll take what I can get. However, when the idler wheel engages, it squeaks, and at first wasn't too loud, but has gotten louder. What can I do to quiet it down short of sending the wheel off to have it rebuilt, is there any way to resurface the outside edge of the wheel to minimize noise and slippage?

Thanks in advance, and sorry if I've asked anything offensively stupid.

 

[Thom]

First off we're friendly folk 'round here whether it be VPI or BSR so no offense taken.
I think you first have to isolate the squeak. If the bearing surfaces are lubed then it could be the rubber tire where it contacts the the platter rim. Clean both with alcohol or "re-grip" which can be bought at printer supply stores. Squeaking indicates slippage which equals wow and flutter so you'll want to make sure that area is working properly. If the idler wheel does not respond to cleaning it could be that the rubber is dead and will have to be replaced. Also, the idler must be perfectly round with no defects or you will hear it. Hope this helps.

 

[littleguy]

Thanks, I gave it a going over with rubbing alcohol already, and I'll poke around for some re-grip tomorrow when things open up, is the radius of the idler wheel crucial? I don't have much experience with turntables, but what I know of physics and mechanical systems says that the linear speed of a point on the outside edge of the spindle is the same as the linear speed of a point on the outside edge of the platter, and as long as the radius of the spindle, and the radius of the drive portion of the platter are the same, it shouldn't matter how they interface.

Point is, if I can be thorough in my refinishing, can I remove the outer layer of rubber on the idler wheel (0.5mm radius difference tops), exposing new rubber, and giving me a better overall wheel.

Basically, this turntable isn't worth sending out for parts for, so if I can make it work with what's in it, I'll be excited, and that also means I'm willing to take some more risks to get stuff up and running, my primary table is (still budget, but much better) a belt drive Sanyo that's had a similar going over as the BSR and seems to be in much better shape. I guess that's what being 20 years newer does.

Thanks again, I'll find some re-grip and hope that does the trick, failing that, time for some fine grit sandpaper, precision calipers, and elbow grease!

 

[jpdylon]

Thanks, I gave it a going over with rubbing alcohol already,

That is the problem. There is something about alcohol and the material used in the rubber of the idler wheel that don't mix well. If you use any kind of alcohol to clean the rubber surface with --it will ALWAYS squeak on BSR idler wheels.

The solution is to wipe the platter contact surface with a damp cloth and let it dry. Then using 1000 grit sandpaper, carefully resurface the edge of the idler wheel. use no chemicals --not even rubber rejuvenator -- or it will squeak.

Good luck.

 

[littleguy]

That cleared it up, there was definitely a visible difference in the drive face of the idler wheel before and after, kind of shiny before (shiny rubber is usually bad news...) and looked like real rubber after, flat matte black.

No squeak, works great!

Thanks again for all the help, I love vinyl, on almost every other medium I find myself trying to turn the volume up more and more waiting for that missing sound, and (not that I don't enjoy my volume from time to time) with vinyl I'm comfortable listening to it quietly, I feel like it's all there, and I don't have to go find the missing part of the sound.

 

[dshoaf]

Here's a couple of other things you might want to look at with those BSR tables:

- Drive motor: This has an upper and lower sleeve bearing. Over time, these will get 'gunked' up. What you'll get is lower torque and slow starting of the motor. The ideal way to fix this is to disassemble the motor and clean the sleeves. Just make sure that the pulley is reseated _exactly_ at the same level off the plinth's surface as it comes off.

- Idler Wheel spindle: Similar with the idler wheel's spindle as above. In this case, you should have a small plastic washer under the E clip that's removed to be able to pull the idler off. Don't loose it as it keeps the idler in place when engaged. Also those little E clips will fly off into the least accessible area of your room so keep a finger on it all the time you're prying the clip off.

- Trip Pawl: This is the piece of metal on the big plastic cog that engages the return mechanism. Similar to the motor cleanliness issue above, its shaft through the cog will become 'gunked' up and will cause the tone arm to start skipping on inner grooves of the LP. You can see it by peering into the hole where the platter spindle comes through the plinth.

- Platter bearings: These sit at the bottom of the platter shaft and support the platter's rotation. By this age, the grease in that race of bearings will be hardened and dried. Fully wash them bearing race but be careful that the bearings don't fall out. BSR was in flat-out high volume mode back in the 70s and their reputation for cutting corners on mechanism such as Sports Cars (think: MG and Triumph) merits some attention as some of the quality of parts wasn't that good - this bearing race being one of those items.

Hope that helps.

Cheers,

David

 

[NoTransistors]

I resent that strangely-worded comment on British engineering.
My former car lasted over 20 years and accumulated over 300,000 miles. It was a 1980 Triumph TR-7 drophead coupe, complete with home-made ice-cold A.C..
To this day, I regret selling the old girl. No rust. No dents, but it did need plenty of work by then, including a complete engine rebuild.
A reliable and solid car.

Seth
Forever Analog and Covered In Parrot Poop

 

[dshoaf]

I resent that strangely-worded comment on British engineering.
My former car lasted over 20 years and accumulated over 300,000 miles. It was a 1980 Triumph TR-7 drophead coupe, complete with home-made ice-cold A.C..
To this day, I regret selling the old girl. No rust. No dents, but it did need plenty of work by then, including a complete engine rebuild.
A reliable and solid car.

Seth
Forever Analog and Covered In Parrot Poop

Hi Seth,

Don't get me wrong, I had my share of British cars and do regret selling my Sunbeam Alpine, too, even more than the Sunbeam Tiger that went before it.

I also was into old Benz's, too, with an 190SL and a 450SL. The nice thing about those cars was that a replacement part fit without messing with it. On a British car, parts usually required all sorts of shimming, trimming and/or fudging to get them to work. It was the nature of the way they were built only.

I'm sure you enjoyed that certain fun-factor that British cars provided as I did. That's what kept me coming back to them over the years.

Today, however, the audio hobby is _far_ cheaper to mess with.

OK, back to the thread.

Cheers,

David

 

[Thom]

Thank you JPDylon for correcting me on that one.

That is the problem. There is something about alcohol and the material used in the rubber of the idler wheel that don't mix well. If you use any kind of alcohol to clean the rubber surface with --it will ALWAYS squeak on BSR idler wheels.

The solution is to wipe the platter contact surface with a damp cloth and let it dry. Then using 1000 grit sandpaper, carefully resurface the edge of the idler wheel. use no chemicals --not even rubber rejuvenator -- or it will squeak.

Good luck.