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Pinging Doug G.

199.47.246.156

Posted on September 18, 2014 at 09:51:08
Cougar
Audiophile

Posts: 4560
Location: SoCal
Joined: June 25, 2001
help with repair of BIC 980 turntable.

 

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RE: Pinging Doug G., posted on September 19, 2014 at 20:08:30
Doug G.
Audiophile

Posts: 925
Location: Upper Midwest
Joined: September 21, 2005
Go ahead. I'm sorry I took so long. I usually check the posts here every day but neglected to yesterday.

Doug

 

I have a BIC 980 and....., posted on September 20, 2014 at 08:12:42
Cougar
Audiophile

Posts: 4560
Location: SoCal
Joined: June 25, 2001
the platter was frozen. I used some liquid wrench penetrating oil on it and waited a day. The platter loosen up and is spinning freely now. I cleaned off the the inside of the platter goes over the spindle. I cleaned the spindle and tried to clean the lower bearing as good as I could without taking everything apart

What I noticed that the platter has a slight out of true warp/wobble. I took everything apart cleaned and relubed it. but still has that slight out of true spin to it even without the drive belt connected. I did buy a new belt just in case tho after all the fixes.

I also noticed the speed control was not stable and that I had to adjust into the positive side to get it to stop drifting but it has a slight instability. The strobe is steady for a few sec. and then move slight forward then stable then slightly backwards. I tried to see if that was in sync with the warp/wobble in the platter but it doesn't seem to go along with it so that may be another issue.

I ordered another Platter and bearing assembly and one extra bearing for this table. Got them cheap.

this table is near mint condition cosmetically so I just wanted to get it up and running for my Vintage system I'm putting together.

Here's what I haven't done yet and will start disassembling and cleaning everything.

1. I have haven't opened examined and cleaned the motor bearing yet.
2. I have not cleaned off all the gears and levelers of the old grease.
3. I haven't cleaned and examined the lower bearing at the very bottom of the platter under the rubber washer.

I have ordered some Panasonic FM 470uf/25Vdc caps for the power supply and hopefully this will help correct the drift issue since they are old. This my help with the Oscillator that controls the motor speed and stability.

Can you help with these issues just incase I missed something? any advice/input?

I appreciate all the help!

 

RE: I have a BIC 980 and....., posted on September 20, 2014 at 15:35:29
Doug G.
Audiophile

Posts: 925
Location: Upper Midwest
Joined: September 21, 2005
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

 

RE: I have a BIC 980 and....., posted on September 20, 2014 at 16:18:54
Cougar
Audiophile

Posts: 4560
Location: SoCal
Joined: June 25, 2001
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!














 

RE: I have a BIC 980 and....., posted on September 20, 2014 at 17:13:09
Doug G.
Audiophile

Posts: 925
Location: Upper Midwest
Joined: September 21, 2005
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

 

RE: I have a BIC 980 and....., posted on September 21, 2014 at 17:13:43
Cougar
Audiophile

Posts: 4560
Location: SoCal
Joined: June 25, 2001
"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!




 

BIC 980 repair Update., posted on September 22, 2014 at 17:51:13
Cougar
Audiophile

Posts: 4560
Location: SoCal
Joined: June 25, 2001
Doug,
I replaced the bearing a platter everything seems better but I did notice when you suggested I check the motor. It's not that resistant I can stop it fairly easy with my index finger and thumb. If it's supposed to be high torque, it doesn't really feel like it. If that's normal then I'm done with the bearing platter side.

Is this something you feel I should open up the motor inspect, clean out the bearing, and relube the motor?

Tomorrow I will start with the caps in the power supply, De-oxit the pot, and the issues with the arm going to the middle of the platter.

I should be done by mid week.

 

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