Sign in   |  Join   |  Help
Click here to tell us about your new email address

Beogram 1200 repair

This post has 91 Replies | 4 Followers

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

Absolutely first thing is to ZERO balance the arm, and that's done with the stylus/cartridge installed. The procedure is shown MOST clearly in the BG1202 / 3000 Service Manual. IIRC, around pg19.

After you've zero balanced it, set the cartridge weight to 2gr. Then on each subsequent LP play, reduce it by 0.1gr, until you find the sweet spot for your cartridge, which could be anywhere from 2.0gr to 1.2gr. 

ChrisG116
Not Ranked
Posts 19
OFFLINE
Bronze Member
ChrisG116 replied on Sun, Apr 13 2014 1:12 PM

Well, the 1203 is back from a random chap I found via ebay who lived quite close and it works like a dream!

 

I'm still unsure what Rex Radio really did when they repaired it because the spindles look like the original ones. This new chap found the problem with the return too, the DIN had been replaced with RCA's and the cable, although a good one, was very stiff so wasn't letting the arm move quite as freely! He replaced that, put in a proper earth cable, and oiled the motor all for £25 and now it's playing beautifully!

 

He said some bushings or springs or something were close to worn out which results in the motor sitting a few MM lower than it should so the speed dial on the side has to be cranked to max rot achieve the correct speed... but... it works.

 

Next up, the 1200 and those awkward little parts!

 

ChrisG116
Not Ranked
Posts 19
OFFLINE
Bronze Member
ChrisG116 replied on Thu, Apr 17 2014 8:05 PM

Works like a charm!

https

watch?v=wYzxosWQhS4

https://www.youtube.com/watch?v=wYzxosWQhS4:800

 

Unlike the video embed option on here...

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

I have a BG3000 - 1973-model radial. Beautiful machine, which I've serviced many of.

But here I have a problem, which I have never seen before.

Common problem - it came in with a non-working motor. My normal procedure is a complete cleaning, oil and shim the motor.

That solves the problem on all the 1202's, 1203's and 3000's, which I've previously done.

I've checked all connections, replaced the diode and capacitor inside the relay, cleaned all contacts.

I disassembled the top and bottom bearings of the motor, removed the old felt discs, put in new felt, didn't help.

But this one - forget it. The motor barely starts rotating, very slowly, and then the slightest pressure from the idler wheel stops the motor.

It's as if it just doesn't have enough juice. Any ideas?

Is this an issue with the BG1202 / 3000?

If not, does anyone have a spare motor assembly, preferably from a 1203?

Menahem

Dillen
Top 10 Contributor
Copenhagen / Denmark
Posts 9,202
ONLINE
Founder
Moderator
Dillen replied on Tue, May 13 2014 8:02 PM

Typical sign of a motor that has been allowed to run with dry bearings (hardened lubrication).
The pores in the bronze material are extremely delicate and soft. Under normal circumstances there
are no direct metal-to-metal contact from the motor spindle to the bearings because the parts have a very thin
film of oil between them, which also minimizes friction and gives a practically endless bearing lifespan.
However, if the motor has run with wrong -, dried-out - or no lubrication, the spindle will have touched the inside surfaces
of the bearings and the bronze material will have been smeared out, closing the microscopic pores in which the
lubricant sits and flows.
One-phase AC motors of the short-circuit type like this has very little initial torque so gathering speed can be very difficult even
with good lubricants and, needless to say, almost impossible with no lubricants.

It's a common problem with all decks using one-phase AC motors, Beogram 1000, 1001, 1200, 1202, 1203, 2000, 3000 etc.
and it's also very typical to see the motor running and working perfectly right after servicing but a month or so, sometimes just
a couple of days, later, it will again be very difficult for it to gather speed.

The only lasting fix is to replace the bearings.

- And please upgrade to a minimum membership level of silver to place wanted ads.

Martin

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

Thanks Martin

So, If I was to lightly sand the inside of the bronze bearings with rolled-up 1000-grade water-paper, would that be a good solution?

Dillen
Top 10 Contributor
Copenhagen / Denmark
Posts 9,202
ONLINE
Founder
Moderator
Dillen replied on Tue, May 13 2014 8:45 PM

That would almost definitely destroy them.
It's a very soft material.
Besides, the inner diameter would end up being too large so an oil film cannot build up and that
is immensely important.

You know from shimming up the motor spindle, that it's very important for the spindle to sit exactly aligned
in the bearings. The tiniest amount of skew and the motor spindle won't run freely enough, that's because an
oil film cannot build (and/or it runs metal to metal on the upper or lower edge of one or both bearings).

I am currently working on a solution to this bearing problem and I will probably need volunteer testers - if you are patient....

Martin

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

Only too happy to help!

I'll look at SKF or other bearings to see if they have a ready made roller bearing solution to fit inside the B&O race, or have you already done that?

Dillen
Top 10 Contributor
Copenhagen / Denmark
Posts 9,202
ONLINE
Founder
Moderator
Dillen replied on Tue, May 13 2014 9:41 PM

I think the friction is far too high in ball bearings but, by all means, go ahead and try.

Martin

Søren Mexico
Top 10 Contributor
Mexico City
Posts 5,881
OFFLINE
Bronze Member

I have had the same problems with my BG 1202, and when I get my BG 1000 over here, I will try with Nylon bushings, I have with success used a product called Nylamid XL, in small electromotors (well bigger than the BG motors), its a polyamide product containing MoS2, and used for self lubricating bushings.

Will be back with more after tests.

Collecting Vintage B&O is not a hobby, its a lifestyle.

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

Soren,

I did some reading on this - looks very interesting.

I have no experience in the plastics area, and I would be very confused trying to choose between all those Nylamid products!

Definitely keep me in mind, and if you want me to test your creations Geeked, feel free!

Menahem

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

Solved.

The bottom line is real simple - when you've got nothing to lose, the world is full of options.

So, I decided to ream out the centers of the brass bearings.

As Martin proposed, the bearing centers were discoloured, most likely due to the smearing.

The motor axle diameter is 2.8mm thick, so I took a drill bit of 2.5mm, and wrapped 1000-grade waterpaper around it, and very gently threaded it in and out, rotating at I go. Took a good few patient minutes.

Then I changed to 2000-grade, and did the same thing.

Cleaned out the detritus with alcohol, and tested for slipperiness over the shaft.

When it was supper slippery, but with no lateral sloppiness, I oiled and reassembled.

The motor is PERFECT!

With these machines, there is ALWAYS something new to learn!

Here is the incriminating evidence!


Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

Spins like a bat out of hell - superb! And the long spindown is exquisite!

Does anyone know the original correct diameter of the Rubber Idler wheel, when the rubber was soft, and hadn't contracted yet?

I had to trim the hardened rubber off the edge (now 55.8mm) and it now spins at almost 45, with 33 selected (30 or 25 on the dial).

I have 2 other spares here, measuring 56mm and 56.8mm, but they're also both fast.

My intention is to send them to Terry Witt anyway for new rubber.

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

OK, so you're reading this and saying to yourselves - what a dumbass Big Smile - he still hasn't fixed the motor - it's rotating 20% too slow. In order to get it to rotate at 33rpm, he has to put the selector at 45......

Well, I started doing the math - I hadn't done this math since I was in university 40 years ago. Wheel ratios, and RPM's etc.

It worked out that in order to rotate the platter at 33rpm, the Rubber Idler diameter needs to be 71mm!!!!!

No way. The maximum idler diameter which would physically fit in the BG is 59mm.

So, either I made a royal screw-up with the bearings, or there was something else.

 

During the calculations, I had assumed that the Brass Pulley diameter is fixed (with a 3% variation), So I went back to the calculations, to solve for a pulley diameter variable which would suit the existing Idler diameter of between 56-59mm.

And I came up with a pulley diameter of 5.6mm.

Then I looked at my own BG1203, which works flawlessly (no surprises there), and I had a double-take. My BG1203 pulley LOOKS fatter than the BG3000 pulley. I pulled out my calipers and measured. Click on the picture to open it fully, and see all the Results.

 

The BG3000 pulley is THINNER. It probably comes from a country with 60Hz  electricity.

My BG1203 was bought in Israel (a 50Hz country) - and has a diameter of 5.6mm on the 33rpm section!

Can anyone in the Americas confirm that their pulley matches the thinner of the 2 pictured below?

And if anyone wants to get rid of a fatter 50Hz pulley (swap for other parts), most appreciative.

 

Soren, I remember that you made up your own 60Hz pulley - were these dimensions close to what you calculated?

 

Menahem


Dillen
Top 10 Contributor
Copenhagen / Denmark
Posts 9,202
ONLINE
Founder
Moderator
Dillen replied on Wed, May 14 2014 8:54 PM

There are different sizes, not necessarily related to the mains frequency.
These are both for 50Hz Beograms but with slightly different motors:

Martin

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

Different motors, eh?

I went back and checked the 2 motors, and yes, they are different.

Now, when I match the motor with its appropriate pulley, the speed is perfect.

I never noticed this before - It appears that this is the first unit I've seen with the thin pulley and wide motor. Perhaps it was a very early production combination.

Anyway, I still like the idea of mismatching the pulley and motor to get 60Hz compatibility!


ChrisG116
Not Ranked
Posts 19
OFFLINE
Bronze Member

This is the part which was allegedly replaced in my 1203... not 100% convinced though.

It's still running nicely... cleaned it all up, takes a song or two to get up to speed but can't complain. Have it linked to some Kef 101's that my dad once owned and the sound is amazing.

Still trying to get the 1202 back working... will part out if I cant...

Søren Mexico
Top 10 Contributor
Mexico City
Posts 5,881
OFFLINE
Bronze Member

Menahem Yachad:
Soren, I remember that you made up your own 60Hz pulley - were these dimensions close to what you calculated?

I didnt change the motor pulley, but made a new poliamide belt pulley instead of the steel belt pulley. The new belt pulley is 20 % smaller than the old steel pulley.

Collecting Vintage B&O is not a hobby, its a lifestyle.

Søren Mexico
Top 10 Contributor
Mexico City
Posts 5,881
OFFLINE
Bronze Member

the wheel is overall diameter 28,5 Mm. the original is 35.4 Mm, so a little oversize, its easier to machine down if too big

And here my thread about it

http://forum.beoworld.org/forums/p/1666/14226.aspx#14226

Collecting Vintage B&O is not a hobby, its a lifestyle.

Christian Christensen
Top 150 Contributor
Stockholm
Posts 512
OFFLINE
Silver Member

Yachmed

One year later, is the beogram till working perfect ?

I have 3 piece of 1200 with this problem , exactly as dillen described, just cleaning and oiling the motor works only for a couple of days.

DIllen,l  volontair if you have some new pieces to try.

Christian 

My re-capped M75 are my precious diamonds.

Søren Mexico
Top 10 Contributor
Mexico City
Posts 5,881
OFFLINE
Bronze Member

Christian Christensen:

Yachmed

One year later, is the beogram till working perfect ?

I have 3 piece of 1200 with this problem , exactly as dillen described, just cleaning and oiling the motor works only for a couple of days.

DIllen,l  volontair if you have some new pieces to try.

Christian 

The problem with the bearings is, as Martin has mentioned, the pores in the bearing clogs up and are nearly impossible to clean. The problem is that the bearing needs oil deposit "holes" it also has to have a dimension (inner D) that leaves space for the oil. Meaning: If the shaft is 2.8 mm, the bearing has to have an inner D between 2,82 and 2.84. Menahem is on the right track with using 1000 and 2000 grain wet sanding paper, but the grains of a 2000 paper are too fine to leave deposit grooves without deposit grooves or holes, the oil will slowly be pressed out of the bearing. I use a 220 grain paper first, cleaning the bearing with acetone before starting. I rotate the 220 paper a few times until the bearing is shiny and clean, then clean the bearing with acetone and then rotate 400 grain paper until the bearing fits lightly over the shaft without oil, adding oil you will feel the bearing fitting a little harder over the shaft. The bearing will now have space for the oil to work and from the 220 grain paper the resting grooves for oil deposit. I use a multi grade synthetic  motor oil for lubricating.

 

Collecting Vintage B&O is not a hobby, its a lifestyle.

Christian Christensen
Top 150 Contributor
Stockholm
Posts 512
OFFLINE
Silver Member

I know nothing about oils.
What is a multigrade syntetic  moto oil ?
Something I can buy in a gas station ? 

My re-capped M75 are my precious diamonds.

Dave Farr
Top 50 Contributor
France
Posts 2,265
OFFLINE
Bronze Member
Dave Farr replied on Thu, Jun 18 2015 10:02 AM
Can you just not use 'liquid bearings' oil? Cheap and available via the Internet and specially made for bearings and it doesn't dry out.

Dave.
Søren Mexico
Top 10 Contributor
Mexico City
Posts 5,881
OFFLINE
Bronze Member

Dave Farr:
Can you just not use 'liquid bearings' oil? Cheap and available via the Internet and specially made for bearings and it doesn't dry out.

Dave.

Liquid bearings is a synthetic oil, but very thin (low viscosity) and is very good  for everything else in the BGs, but the AC motor is running fast and need a little "thicker" oil. synthetic oils has longer stand times and are more penetrating than petroleum based oils. In the slower running DC motors Liquid Bearings will do.

I use the multi grade oil for the platter bearing too,

A 20/50 synthetic motor oil can be obtained at any gas station.

We are working with self lubricating bearings made in the 60s, in the 1960s the sintered bronze bushing production process began to become more sophisticated, cheaper and more popular with producers, with newer and better materials this has continued into the 70s and early 80s. A sintered bronze bushing is bronze with up to 25% holes in it, these holes gets filled with oil in a vacuum process.In the 70s and until today the self lubricating plastics took over a great part of this market.

Oils evaporate or "dries" out, so after 40-50 years there is nothing left in a bushing which means that we will have to find a way to get some lubrication in there, or change the bushing with a new one. If these decks was produced today there would have been a whole lot of more plastics in them.

 

Collecting Vintage B&O is not a hobby, its a lifestyle.

ChrisG116
Not Ranked
Posts 19
OFFLINE
Bronze Member

Incorrectly relied to another thread so have copied and pasted....

 

I'm back. Some new info and some new requests!

the 1203: it all got fixed. Turned out the cable from the arm had been replaced with one that had stiffened up over time! New cables and a few tweaks and she's good to go. That was about a year a go and a new problem has come up... It's taking ages to pick the arm up. After the first play it takes less time. Maybe the cable again? Going to take it to the chap who fixed it for me last time. Bit worried it's finally shot though as the suspension is very baggy and its sitting a bit low in the case 

 

the 1200: still nothing but given it to a friend who is a good tinkerer, hopefully he can fix. 

 

Since I first posted in this thread I've invested a bit more into my hifi system and when the 1203 works it plays like a dream through my A&R A60, and they match each other beautifully aesthetically. I'd love to find someone who can reliably service these decks so one of them will last me for a while. If anyone has suggestions or recommendations for someone UK based that would be very much appreciated. There is some chap on eBay offering repairs but for £200 a deck. I don't mind paying but that's quite a bit. 

 

Hope me someone here can help. Again. 

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

Chris

200 Quid is not a lot at all, if the job is done right.

You cannot measure a vintage repair in terms of currency alone. You have to measure its value - what do you get for that cash outlay?

 

It is the very rare technician whose work is of such a high standard, that his repairs are indistinguishable from the factory original.

When a competent technician has to start retracing the work of the sloppy tech who "had a go" at the machine before him, that cost has to be figured into the whole repair.

 

I have refused many projects because I know what is involved in retracing a previous tech's sub-standard work. 

 

Electronic repairs are like sex - once the covers are off, your work is there for all to see - you can't hide anything.

Get real-life references from previous customers, and if the tech is praised for his high standard of work, don't ask about the price.

 

There are a handful of good UK B&O techs on this forum.

Why don't you post a new thread with a Subject - Looking for BeoGram tech in the UK ?

 

Menahem Yachad

Israel

ChrisG116
Not Ranked
Posts 19
OFFLINE
Bronze Member

Hi Menahem,

Thanks for the reply. If £200 is the going rate then maybe I will have to pay it but was hoping for a little less as old equipment like this can be a money pit, I've already spent over £100 on it mostly on a chap who claimed to be a B&O expert. Will make a post as suggested and see who replies, I've also mailed everyone mentioned in similar posts. 

Thanks,

Chris. 

beobeo12001200
Not Ranked
Posts 9
OFFLINE
Bronze Member

Hi everybody,

I'm COMPLETELY new to all of this.  I've wanted a turntable for a while now and was deciding between vintage and new, until I saw the beograms and thought--wow, that's just the most beautiful turntable I've seen.  I just love that B&O aesthetic and even though some of the modern ones are more advanced, they don't come anywhere near this beauty in terms of their looks.

So I looked at ebay--I could find a few at around 150 GBP, allegedly working, but who knows how well?  And who knows how good the stylus is after all these years?  And then I saw a Beogram 1200 in a very good cosmetic condition but labelled as "for parts only," without a stylus.  It was offered at 100 GBP, which was obviously a joke, so I offered 30 GBP and the seller agreed.

I figured--maybe it will be a simple fault, like a shot belt, in which case it will be an easy win and then I can buy new-ish stylus online for about 170 and have myself an awesome-looking deck with a new stylus at more or less the same price as the other ones.

Or it will be a more complicated problem, so it can become a little project.

Worst case scenario, I'll mess it up and have wasted 30 GBP--worse things have happened.

So I bought the damaged Beogram 1200 and dived in a little last night.  When plugged in, it makes a faint buzzing sound and that's about it.  Nothing moves.  The motor spindle get a little warm after a while (I think, I never plugged it in for more than 2 minutes).  The gear wheel mechanism seems to be working pretty well when moved by hand, all of the arms are doing pretty well, but I guess they should still be lubricated.  Plus--who knows how they actually do in practice because the damn thing won't actually turn on.

I'm going to buy a voltage checker tomorrow, but I don't suspect that will be a problem, because the motor is definitely buzzing a little, suggesting at least presence of current.  Having read this excellent thread throughout, and some others here and there, it seems to me that a strip-down of the motor is in order.  I've never however done anything more electrical than changing a lightbulb and plug in my laptop, so, I'm a bit apprehensive about stripping down the motor (I'm pretty sure I learned about motors in physics classes way back, but, boy, it's been a while).  

So--do you know of any video or good article here on how to clean motors?  I haven't found any.  Or are any of you in London and able to give me a hand at a fair price?

Like I said, I mostly see this as a "let's see if I can fix it" project.  If I succeed, I'll be happy, if I don't, I'll buy a functioning one.

Oh, also, I removed the record guide in order to lift up the plate and check out the belt (it seemed fine but I bought one anyway).  But now I can't seem to be able to put the record guide back in.  It seems there is a little tiny spring within the plastic inner shell of the record guide that moves freely and could perhaps be blocking it as I try to fit it back on the spindle.  I have a feeling there's a trick to this that I don't know.  Any ideas?

I'm really grateful for all of your (anxiously anticipated) help.  Sorry I'm just another newb trying to learn from the gods.

Thank you!

 

 

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

AFAIAC, the 1200/3000 series is one of the best radial TT's made, built like a tank, and easily maintainable, as long as you don't try to cut corners, or be lazy.

You already perceived the most important fact about these "allegedly working, but who knows how well".

None of these TT's, no matter how the seller may describe them in glowing lexicon, is working properly. All need work, and I'll explain why.

 

1. The AC motors are all, generally, in excellent shape, and very few require disassembly.

However, in order to work properly, they are entirely dependent on the quality of voltage which reaches them from the AC outlet.

There is one component which literally "gums up" the works. That is the AC voltage selector switch. EVERY ONE requires complete disassembly and cleaning - Be careful - there is a tiny spring and ball-bearing which can get lost easily.

I use Brasso wadding to wipe off all the oxidation and hard grease, followed by Kontakt 60. After the cleaning, the motor works perfectly.

 

2.  The Idler wheel's rubber is completely hard, and useless for maintaining any semblance of friction against the brass pulley cone (on the motor shaft). That has to be re-rubbered. For many years, I have been sending all mine to Terry's Rubber Rollers in the USA. He does an EXCELLENT job.

Without taking care of the above 2 issues, you have absolutely no hope of ever having a perfectly-functional machine, no matter what the seller claims.

 

The buzzing you hear, is NOT the motor. It is the solenoid vibrating at high frequency, because the pusher unit (in a closed plastic case under the platter) is not aligned correctly. The alignment is controlled by

1. A little black plastic tab, which may be missing or deformed. Rudy Schaf (Beolover) in the USA, is making replacements for these.

2. The contact switch underneath the LIFT button. You need to rotate the actual switch slightly on its axle, until it makes an exact and positive contact when you press the LIFT button.

 

The machine must be turned upside-down, and supported on wooden blocks to prevent damage to the tonearm.

 

In the rotating axle's white shaft under the platter, there is a small black pin - if it is not EXACTLY in the centre of the shaft, the axle will knock, and you'll have speed problems.

A few drops of bearing oil into the shaft of the up/down control for the tonearm, is advised.

 

So there you go.

You already have a top unit.

Bite the bullet, do the work as I've described, and you won't look back.

If it's more than you can manage, there are a couple of good UK techs - start with Nick (Solderon)

 

Menahem

beobeo12001200
Not Ranked
Posts 9
OFFLINE
Bronze Member

Hi Menahem,

Thank you so much for your great message.  I really appreciate your help.

I do, however have a bunch of more questions... 

1. The voltage selector--how can I disassemble it?  It's a small switch with a bunch of wires coming out of it on one side, and the other side having presumably some electronics hidden under a black plastic selector wheel that can be switched between 110V and 210V.  Do you mean I'm supposed to remove the black plastic round switch and clean what's underneath it?  If so, how do I do it?  I couldn't figure out how to remove it from the brown tab that it sits on.

2. I agree re the idler wheel, but kind of first want to get the motor to spin and then worry about the wheel (which it seems to me doesn't quite maintain contact well with the spindle so that will have to be fixed (probably lubed).

3. Re the buzzing.  Can you be a little more specific about the little black plastic tab?  I couldn't find it (which may well be because it's missing!) but when I looked at other photos of the disassembled turntable that other people posted online, I saw no difference between mine and theirs, so I don't quite know where to look for this black plastic tab.

4. The contact switch--as far as I can tell, it's not an electrical component and instead is purely mechanical.  The suppression of the black lift button moves a metallic arm, which moves another arm.  As far as I can tell, it makes contact quite while and moves the arm in its full range of motion.  Am I missing something here?  Is it in fact an electrical switch?  

5. I haven't yet looked at the rotating axle, but I will tonight.

Sorry I'm basically asking you to help me more on the stuff you've already said.  It's not that I did not try to fix it--I spent at least 2 hours last night tinkering with the turntable and trying to find what you're getting at--I just haven't been successful!

Thanks so much again,

Honza

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

The little black plastic tab is circled in red.

It is called an "eccentric", because when you insert a small flat screwdriver and rotate it, it causes the mechanism underneath to displaced in an elliptical motion.

The objective is to find the sweet spot, where no buzzing occurs when you push the LIFT button, and the Tonearm moves correctly towards the LP.

Click on the picture to display it fully.

 

BTW, I drilled an exact position hole in the underplatter, to provide easy access for adjusting the tab, without having to remove the belt and underplatter each time I needed to adjust the tab, in 10-degree rotation increments.

Also, because you do NOT install the main platter during these adjustments, and because the platter mechanism needs to be weighted down, so I put a roll of solder in the center of the underplatter.

If not weighted down, the belt unravels during rotation!


Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

This is the underside of the LIFT button

This is a really dirty switch,  sick with oxidization.

Repeated wipings with a Brasso-impregnated strip of thin cloth solves the contact problem.

Again there is a sweet spot for a correct contact, by releasing 1/4 turn the bolt which secures the black-plastic housing to the aluminum chassis, then rotating the black housing until the switch works just right - no buzzing. Resecure the bolt.

The machine has to be upright on blocks to provide correct access and view from underneath.


Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

I don't have any pictures of the voltage switch.

However, this is the procedure.

Lay down a white sheet on the floor on which you and the BeoGram will sit, and that is where you are going to do this procedure, because the little spring and ball bearing are sure to jump away from you, because at this stage, you are not accustomed to the correct way to do it, without losing these tiny parts.

The black voltage switch must be lifted away from its holders, so that you can turn it over, and expose the underside clearly.

Do NOT disconnect any wiring.

In the square centre of this switch bottom, are 2 flat (but triangular) plastic tabs, which are part of the upper cover, which push down through the switch's centre, and grip the bottom half of the switch.

With a pair of flat-nosed pliers you will grip these 2 tabs and squeeze them GENTLY towards each other, while encouraging the upper cover away from the bottom part.

It will help if you have a friend to do this with you.

The spring and ball bearing will jump away from you during this time, and you will find them on the white sheet.

You have now opened up the selector switch.

There are many little bits of metal which all need to be Brasso'd until absolutely shiny, wiped off, and then wetted with contact cleaner.

Do NOT wipe off the contact cleaner.

Don't worry about reassembly - it can be assembled ONLY in the correct alignment.

Play with it before final reassembly, to ensure that you understand the alignment.

I hope that's all clear!

beobeo12001200
Not Ranked
Posts 9
OFFLINE
Bronze Member

Ah, you're awesome.  Thank you!  I'm on a train home and will get on this as soon as I have dinner. 

But, it occurs to me that you have the 1203 whereas I have the 1200.  I'll send pictures of the insides of mine, but I can see there are differences--your lift button has entirely different mechanics from mine. 

ill upload pics when I get home--the project for tonight will be the voltage selector (thanks for the detailed info).  

The buzzing sound aside--the motor should run even if the buzzing occurs, right?  

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

I don't have the 1203, or the 1200. All photos were taken many years ago, when I had a particular model in for service.

However, the entire 120x, 2000, 3000 series ALL operate the same, and use 99% identical parts.

Take a close look again at your 3000, and you will see that everything to which I referred, is there, just as I described it.

 

Thinking of correct operation, the motor starts after the buzzing stops - of course, the buzzing shouldn't be there anyway.

The buzzing is the "bad" start of the rotation, so buzzing means that rotation was not able to start.

Dillen
Top 10 Contributor
Copenhagen / Denmark
Posts 9,202
ONLINE
Founder
Moderator
Dillen replied on Tue, Mar 7 2017 9:09 AM

Menahem Yachad:

However, the entire 120x, 2000, 3000 series ALL operate the same, and use 99% identical parts.

 

Confused

I continue to be amazed at how different we see things, Menahem.
- And how different our experiences are.
I have repaired hundreds and yet hundreds of Beograms of these types and yet, you often
suggest repairs to areas that I never ever saw a problem with and would never dream of focus'ing on.
I have seen very few bad power selector switches in my life and they were either broken by misuse or
damaged by water, lightning strike or something else uncommon.
If oxidated, just rotate back and forth a couple of times and they'll be fine.
And they were all in Beomasters - never saw a bad one in a Beogram.
I'm not saying that it cannot happen - of course it can, lots of things can happen and things
could easily be different in other territories due to temperatures, weather, airs moisture etc..
It's just not something I have seen here - even on decks from the middle-east or Asia.

Your experience is that practically all of the AC-motors are still running fine - mine is
exactly the opposite in that almost all decks of these types that I have on the bench is in need
of a thorough motor/bearing service.
Some have seized to an extent where, if you rotate the motor spindle by hand, the spindle is not
rotating in the bearings, - it's the bearings that are rotating in their holders.

But let's stay with facts. We cannot disagree on facts - can we?
Well, perhaps, unless we disregard your saying that Beogram 1200, 1203 uses
99% identical parts - because that's simply not true.

Despite some of the operation principles and design similarities Beogram 1200 and 1203 share only very few
components - apart from a few screws and other minor parts they are almost entirely different.
The operation is different, buttons are different, suspension different, tonearm, electrics, adjustments etc.
(And that goes for both versions of Beogram 1203, which again are far from identical inside).
Beogram 1203 is full-automatic, Beogram 1200 only semiautomatic.

And Beogram 1200 doesn't have any of the contacts and adjustments you refer to.


And then my attempt to help Honza;

If very faint, the buzzing will most likely come from the motor. If very audible it could be an oxidated switch, but that's rare.
The vast majority of these AC motors will have seized up in old and dried lubricants to some
extent by now and will be in need of a thorough service. That's quite normal.

When you tell, that the deck is buzzing and the motor warms up, it could confirm that
the motor has seized.

Is the belt on correctly?
Does the motor rotate easily by hand?

Martin

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

Martin

Because I may have been amiss in not being absolutely clear, allow me to clarify the above statement - "However, the motors of the entire 120x, 2000, 3000 series ALL operate the same, and use 99% identical parts". And that's what we're focused on here - the motor function.

Anyway, sorry for the unintended misunderstanding.

Regarding the rest, however, I can speak here based only on experience.

I have had to rebuild the motor only ONCE, in about 25 years, over tens of these machines. And that was so unusual, for ME, that I made a thread about it here on Beoworld.

Any time that I have a slow-running motor, which would by all symptoms appear to be seized, I always overhaul the AC selector. And that's always solved the problem (of the slow motor, that is). So, for me, that's my "goto".

Every tech has his automatic list of "goto" fixes in priority order, when he is familiar with a particular series of machine. That "goto" priority is based on that tech's personal experience.

So, I'm sharing my "goto" list, which may or may not be similar to yours, and that's just fine.

The important thing is that the owner covers all possible bases, and ends up with a fully-functioning machine, and a smile on his face.

All done in good spirit, and no offense taken when we differ Yes - thumbs up

As far as overhauling the motor, go for it. You've done many more than I (exactly one), and Honza deserves the best advice possible.

Menahem

beobeo12001200
Not Ranked
Posts 9
OFFLINE
Bronze Member

Hi everybody,

thanks for the variety of responses.  

Menahem--I looked at the voltage selector, but it didn't match up your description; there was no way for me to dismantle it other than cutting it in half, so I didn't.  See pictures below.  However, I did use some contact cleaner on it AND AFTER I DID THE MOTOR STARTED MOVING!  Only about 15 degrees in the 10 seconds that I plugged it in, but better than nothing.  

I think applying electrical contact cleaner is about as far as I can get with this voltage selector.  Do you think otherwise now that I supplied pics?

I got a voltage checker so that I can double-check voltage around the circuit--does anybody know how much it should be?

I can now also confirm--thanks Martin--that the buzzing comes from the motor.  I turned the voltage selector to 110V briefly and it started moving a bit more and buzzing a lot more.  So I think a clean and oil is in order.  I have brasso and the contact cleaner.  I also bought a thing of sewing machine oil.  Are those all the tools that I need?  Is there a guide on how to properly clean and lubricate these motors somewhere?  At the beginning of this thread the guy showed some pics of the disassembled motor but I wonder if there's is a bit more in terms of know-how.

Also--here are just general pictures of the deck in case any of you see something out of the ordinary.

 

 

Thank you again for all the help!

Menahem Yachad
Top 75 Contributor
Jerusalem, Israel
Posts 1,113
OFFLINE
Bronze Member

Wow! You refreshed my memory of those Voltage Selectors which I haven't seen, for I don't know how long. Those are riveted, and not able to disassemble.

The best is to spray contact cleaner in through the wiring holes from underneath, in the hope that some fluid will penetrate to the contact.

I would also check the ohms between adjacent wires. The reading should be either less than 1 Ohm (closed, with the contacts in good condition) or some KOhms (open, but in the circuit).

If you see that some reading is higher than 1 ohm, then the associated contacts are oxidized, and further work is necessary.

Understand that the higher the ohm resistance on those contacts, the LOWER is the voltage reaching the motor, which reduces the motor's ability to rotate correctly, if at all. 

When those contacts are shiny clean (which in your case you cannot see) and provide ZERO resistance to the required voltage, that well-engineered motor rotates perfectly, assuming no detritus in the motor bearings - as Martin described.

Martin asked previously how does the motor feel to your fingers, if you rotate the brass pulley cone by hand, with the platter and belt off. 

beobeo12001200
Not Ranked
Posts 9
OFFLINE
Bronze Member

Thanks!

And sorry about not answering Martin's questions--the brass pulley is VERY hard to rotate by hand, so I think it's a case of a stuck motor.

I know this is probably the dumbest question, but how exactly should I measure the resistance?  I'll set my voltage meter to ohm, of course, and then just make my way between the cables, doing, e.g., red & brown, then brown & blue, etc., as I complete the circle?

Honza

Page 2 of 3 (92 items) < Previous 1 2 3 Next > | RSS