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In Reply to: RE: I have a BIC 980 and..... posted by Cougar on September 20, 2014 at 08:12:42
A very slight warp of the platter shouldn't be a real concern. However, if there is play in the bearing, that's bad. If you grasp the platter on each side and try to rock it on the bearing, there should really be no play at all. If there is, it means the bearing is worn.
Another possibility is that the O-ring on top of the washers and ball bearing is worn or expanded. It should fit tight enough on the platter at the bottom so it doesn't fall off. If it's too loose it will move around as the platter rotates and cause noise and wow/flutter.
The most likely cause of speed instability is the pitch control itself. It is a potentiometer and can get dirty inside. Use De-Oxit to clean it or you can even try just turning it back and forth rapidly several times. That will clear the dirt out of it, sometimes.
You should remove all the bearing parts, clean them, re lube, and replace. This can be done by lifting them past the blank spot in the big red cam without any real disassembly. You can use a Q-Tip to clean the bottom where the lower washer rests.
If the motor seems to turn OK and is fairly resistant to stopping if you grab the pulley, it is OK and I wouldn't mess with it.
Whether or not to service the entire mechanism will depend on if all the automatic functions work normally.
I wouldn't replace those capacitors on the speed control board unless they are leaking or otherwise display signs of malfunction. You may have to recalibrate the board if you replace them. Probably not but maybe.
Doug
Follow Ups:
Hi Doug,
Thank you for the reply.
"A very slight warp of the platter shouldn't be a real concern. However, if there is play in the bearing, that's bad. If you grasp the platter on each side and try to rock it on the bearing, there should really be no play at all. If there is, it means the bearing is worn."
yes, slight warp and no play on the bearing so that should be fine.
"Another possibility is that the O-ring on top of the washers and ball bearing is worn or expanded. It should fit tight enough on the platter at the bottom so it doesn't fall off. If it's too loose it will move around as the platter rotates and cause noise and wow/flutter."
Now this could be the culprit, the O-ring has a good amount of distance all around the spindle and to me looks like too much clearance. The platter may sit on it but maybe not how it's supposed to. The new bearing with O-ring should be here on Tuesday so I will know then.
Is there an off the shelf O-ring that I can use in place of the original O-ring that will work properly?
"The most likely cause of speed instability is the pitch control itself. It is a potentiometer and can get dirty inside. Use De-Oxit to clean it or you can even try just turning it back and forth rapidly several times. That will clear the dirt out of it, sometimes."
I will De-Oxit and clean it up correctly.
"You should remove all the bearing parts, clean them, re lube, and replace. This can be done by lifting them past the blank spot in the big red cam without any real disassembly. You can use a Q-Tip to clean the bottom where the lower washer rests."
Ok, I will do this really good. I was using lithium grease but would regular 30 weight oil be good? Or some of that De-Oxit gear and machine oil?
"If the motor seems to turn OK and is fairly resistant to stopping if you grab the pulley, it is OK and I wouldn't mess with it."
Ok, I will inspect and leave alone if everything is ok.
"Whether or not to service the entire mechanism will depend on if all the automatic functions work normally."
No, the arm lifts and goes all the way to the middle like it wants to play a 7" single record. I looked underneath and saw the two mechanisms are sticking together when the automatic is engaged. I know these are supposed to move independently of each other so some cleaning or penetrating oil should help that.
"I wouldn't replace those capacitors on the speed control board unless they are leaking or otherwise display signs of malfunction. You may have to recalibrate the board if you replace them. Probably not but maybe."
I know I will have to readjust that one pot to center the speed control anyways and the main caps shouldn't throw the cal off. I know messing with the other film caps will mess up the cal since that has to do with the stability of the motor. Those IC's set that motor up and controls the stability also.
I will post back later in the week to see what I have found, what works, and what don't work.
Thank You for all the help! I really appreciate it!
Yeah, it sounds like the O-Ring has expanded. I know others have found the correct size at typical hardware stores but I don't remember the size. You could just measure the diameter of the platter spindle below where the gear teeth are and take the old one with and get one that has the same inner diameter and about the same thickness.
Other than that, Adam at Turntable experts has the originals.
30 weight motor oil works very well for the platter spindle. The original was 90 weight differential gear oil and, while it works real well for damping, it eventually turns to glue/cement and freezes the platter on the spindle.
Yup, the two levers/cam followers need to be freed up for the tonearm to land where intended.
OK on the caps as they are just filters and probably won't affect the oscillator.
Good luck!
Doug
"Yeah, it sounds like the O-Ring has expanded. I know others have found the correct size at typical hardware stores but I don't remember the size. You could just measure the diameter of the platter spindle below where the gear teeth are and take the old one with and get one that has the same inner diameter and about the same thickness."
I will look into this. Hopefully, I van find one or even better the original O-ring.
"30 weight motor oil works very well for the platter spindle. The original was 90 weight differential gear oil and, while it works real well for damping, it eventually turns to glue/cement and freezes the platter on the spindle."
I will use this on the next bearing install.
"OK on the caps as they are just filters and probably won't affect the oscillator."
They shouldn't affect the oscillator circuit, the film caps most certainly will and then I would have to recalibrate that circuit. If anything, the Panasonic FM caps should be a big improvement due to the noise removal in the circuit.
Thank you for all your help!
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