BeoGram

Re: 4002 Speed Variance

Dillen — Mon, 08 Sep 2008 15:37:53 GMT

Bill,

The motor we talk about is the one for the platter. It will need a good acid-free oil (sewing-machine oil) or similar to it's bronze bearings.

Isopropanol (tapehead cleaner) will clean off mote of the old lubricants.

Martin

Re: 4002 Speed Variance

bblueser — Mon, 08 Sep 2008 14:29:57 GMT

Ok, I'll give it a shot after work...

Should I use the silicone grease I've seen referenced in this forum? If so, do you know if it has certain qualities, i.e., dielectric, or is it simply silicone grease?

Bill

Re: 4002 Speed Variance

Dillen — Mon, 08 Sep 2008 14:14:35 GMT

Check the motor by tapping it as I described above. If faulty, repair the motor. New motors are practically impossible to find and their lubricants will have dried out as well.

Martin

Re: 4002 Speed Variance

bblueser — Mon, 08 Sep 2008 14:03:41 GMT

Great info...Now, if only I had photos showing locations for the speed trimmers and relay you refer to - along with a brief tutorial on how to check them - I'd be forever grateful

Do you know of any such online tutorials, or source for a new motor, etc.? Also, I assume it's necessary to use a B & O motor and not a generic one (realizing that B & O probably didn't make the motors themselves, but bought them from a vendor).

Yes, I am new at this, but I'm determined to get my 4002 back up to speed! (pun intended)

Thanks,
bill

Re: 4002 Speed Variance

Dillen — Mon, 08 Sep 2008 12:10:37 GMT

Yep. It can be the motor itself. You can confirm this by tapping the motor gently with the handle of a screwdriver or similar while it runs and listen for speed changes. Due to its nature, piano or violin music is especially good for checking this. The motor will need dismounting, taking apart and lubricating. It can be done if you are careful.

Finally, it could also be the speed trimmers and/or the 33/45 relay, all of which are on the main PCB board. Could also be the belt but from what you write my bet is on the motor.

Martin

Re: 4002 Speed Variance

bblueser — Mon, 08 Sep 2008 11:41:47 GMT

Thanks for the reply. Other than the belt, do you have any information on possible causes for a platter speed variance (on 33 1/3), given the fact that the motor is relatively new, and the turntable was rebuilt only a few years ago?

Re: 4002 Speed Variance

Craig — Mon, 08 Sep 2008 11:34:47 GMT

Hi Bill and welcome to Beoworld, I use a Silicon Grease to lubricate the drive for the arm. Not sure where you can get some though, I managed to aquire half a large tube from a mechanic I know. Seems it used on some cars for the plug leads. If you do need a belt kit then one of our members can supply a kit with both the belt for the platter and the one for the arm. His user name is Dillen. Just send him a PM.

Craig

4002 Speed Variance

bblueser — Mon, 08 Sep 2008 10:48:53 GMT

I am new to this forum, and have read several responses regarding irregular 33 rpm speed on a 4002.

My 4002 was rebuilt about 10 years ago using B&O parts. Since that time, it hasn't been used enough to wear out the motor, but when I play a record the speed sounds as it should initially, but a few minutes later the speed varies noticeably.

I removed the top cover and the belt looks fine (and doesn't slip when I hold the platter while the motor turns). I then removed the platter and the only possible issue I observed was the gears at the back of the table (that moves the tone arm across a record), appear dry and a little dusty.

Besides the possible need for cleaning and lubricating these gears, are there any other items I can check myself?

Finally, what type lubrication should I apply to the gears, and is it possible that the belt is slipping, even though it doesn't appear to do so?

Thanks,

Bill