Beogram 4002/4004: DC Motor Restoration - The Cure for RPM Problems

[@zonker92]

Thanks so much for the video; huge help. (I found that the opening of an 11mm Craftsman socket nested inside 5/8” socket made a perfect backer for that upper bearing retainer, when it was time to crimp its ears from above.)

[@simonlaw1862]

I am new to the 4002 turntables. Thank you for the education!

[@donforrest3526]

Well done! Very informative. Thank you for taking the time to makes your videos.

[@agegroot5666]

Found that device together with a Revox B690 on a high shelf in my brothers kitchen. He bought it secondhand together with 2 B&W DM70s in 1980. The turntables were there on that shelf for more than 3 decades. I asked him what kind of devices it were, couldn't see it but when i heard it were a B&O and a Revox turntable i was surprised and very curious to try it. Started with the Revox but when i powered it a capacitor went up in smoke causing a disgusting smell, the B&O worked but the liftingmechanisme didn't work. Took them to my home bike>train>bike. Removed the blown capacitor and the Revox with Shure 97 worked well it seemed but after some time the arm suddenly started to return after just 1 or 2 minutes. Opened the device and i saw 3 Ptc's, two looked ok, one looked terrible, degraded, think 50% was gone, broken off. The others looked OK but might be faulty too. This might be the cause of the unwanted returning of the tone-arm. It's a project i have to finish, think it's best to replace those three and the el-capacitors on that board. The B&O works well after i cleaned and lubricated the arm mechanism, the belt was in a great condition, no degradation during those 30 years standstill. In the beginning the device had some annoying speedvariations after playing 16 til 18 minutes of the record but that solved itself and i don't know how. Reading this story, should i recap the big main capacitors?

[@beolovervideos]

The speed variations will most likely come back. In the beginning they are intermittent, and then it gets worse. We usually replace all electrolytic capacitors when we restore a Beogram. See here for an example (scroll down a bit - this post discusses our entire restoration process): beolover.blogspot.com/2024/03/beogram-4002-functional-restoration.html.

[@raneilalonzo]

I appreciate your effort and expertise.

[@stigbo]

Thanks and Respekt from Denmark💪🏻😷🇩🇰😍

[@robertnicholson7733]

Hi, very nice video, just a slight technical issue. The bearing are most likely sintered bronze not brass. Brass would not be porous, sintered bronze is one of, if not the first, main application of powder metallurgy. The bushing is made by pressing the powder into the required shape under very high pressure and temperature thus creating a hard but porous metal. They usually come pre-impregnated with lubricant. I must try the experiment of filling the jar with hot oil and hot air then quickly putting the lid on. Once it cools, the contraction of the air will cause a partial vacuum. Of course, I do not want to shatter the glass. Might be useful for those without vacuum pumps.

[@lsdave]

If i had a vacuum sealer, do you think it would be of benefit to vacuum seal the bearing with some oil for 24 hours?

[@anbui4392]

this is great! but i have neither the patience, eyesight nor fine motor skills for this! will have to send you the motors for restoration

[@AMusicStoreOnMainSt]

Hello Beolover and all, On my 4004, right next to the platter motor three prong female receptor there is another three prong female receptor. I'd like to know what that receptor is for. Thanks for this video. George at A Music Store on Main Street.

[@beolovervideos]

The second connector is for a 'power on' LED that some versions of the 400x have installed. In most versions it is not used.

[@raneilalonzo]

Great instructions!

[@leroywhite2746]

Hey Beolover! Very good tutorial. I did the repair myself and it worked out fine but the motor seems to work quite a bit too fast now. Can you tell me what I did wrong?

[@beolovervideos]

Sorry to hear! Most likely you damaged one of the two pickup coils that are on the brush carrier. It easily happens during extraction of the lower bearing. In most cases this can be fixed, but it is a bit of 'microsurgery' to get the leads connected again (see here: beolover.blogspot.com/2019/01/beogram-4002-dc-motor-restoration-and-coil-repair.html). Send me an email at [e-mail] if you would like to send the motor for repair.

[@sol756db]

fantastic!

[@nealsausen4651]

No! no! no! Too intimidating I don’t trust myself to do this End of work! to many tiny little parts and I’ll screw it up! if my motor needs any work done on it I’ll send it to you beolover and pay you to do it Interesting video to watch though very insightful fascinating insight into how this Remarkable machine works though! But I’m not going to do this kind of work my hands and fingers are too big for those tiny tiny little parts and I’ll screw it up I leave this kind of work to the professionals the experts like you beo lover!

[@paulpaulzadeh6172]

this guy is brutal , he destroy the motor

[@crisfiler6128]

Don't be silly, he clearly knows what he is doing!