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What Are You Working On Now

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Menahem Yachad
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Very nice.

B&O used a slightly different technique in the other decks, using a rotating ferrite wheel (which generated a local electromagnetic field), in close proximity to a reed switch. As long as the reel table motor was rotating (which, via a belt, drove the ferrite wheel), then the reed switch remained closed, and the head remained in the PLAY position.

As soon as the ferrite wheel stopped rotating, the electromagnetic field dissipated, the reed switch opened, the head retracted to the Eject position, and the motor stopped.

The Hall sensor method is far more precise and accurate, but very expensive comparatively, in order to achieve a similar goal as the cheap ferrite wheel.


chartz
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chartz replied on Wed, Feb 25 2015 12:31 PM

In the Beocord 5000 there is a ferrite wheel with a silicon hall sensor. So this must be something else. Confused Unless this system had been present in early decks and the dented wheel was left for no reason? Mmm. This wouldn't be a first.

 

 

 

 

 

Jacques

Orava
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Orava replied on Wed, Feb 25 2015 12:48 PM

At tape counter, yes.  The "bladewheel" is also a bit loose, so it cant be for anything accurate...

 blah-blah and photographs as needed

Ricardo
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Ricardo replied on Thu, Feb 26 2015 11:12 PM

Clearing a jammed door. One of the door guides (tab) had become wedged between the track guide and the CD cover that had worked itself loose.. I had to remove the door then reset the CD cover in place then put the door back in,

 

 

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Dillen replied on Fri, Feb 27 2015 12:17 PM

Correct, not accurate at all.

But it's not ferrite. It's a rotating magnet.
It causes the reed relay (or hall sensor) to pulse on/off.
The signal from the reed relay (or hall sensor) is fed to what is basically a
simple re-trig'able one-shot circuit. Timing of the circuit is set long enough
to allow for wind/rewind as well as play.
If no pulses are received for a certain amount of time the circuit
times out and the deck is stopped.

This type of motion detector is widely used by B&O.

Martin

chartz
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chartz replied on Fri, Feb 27 2015 12:31 PM

Yes, and in one of my two 4715 (the one pictured above), the hall sensor was bad so I learned the hard way. In older decks like the BC2200, a reed relay was used. The drawback was noisy rewind and fast forward operations, you could hear the thing work at every turn of the magnet!

Jacques

Dillen
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Dillen replied on Fri, Feb 27 2015 12:37 PM

Yes. Laughing
It produces a very faint click sound but it seems to be amplified somehow by the construction.
The hall sensor is completely quiet, though.

Martin 

chartz
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chartz replied on Fri, Feb 27 2015 12:50 PM

RaMaBo:
The main use is to rotate and influence the Hall sensor (small black cube with two soldered wires) right behind. This sensor gives pulses for each 'cutting edge' when they pass by. Based on those pulses the deck control logic knows whether the tape is still moving or blocked (or cut).

 

And by the way, the black cube Ralph-Marcus mentions is the bulb housing for the cassette spool back-lighting! But methinks he was kidding Stick out tongue

The mystery remains...Wink

Jacques

chartz
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chartz replied on Fri, Feb 27 2015 12:59 PM

But seriously, it is only a braking system. But you can't see the arm when the carriage is out!

Jacques

Dillen
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Dillen replied on Fri, Feb 27 2015 1:01 PM

chartz:

RaMaBo:
The main use is to rotate and influence the Hall sensor (small black cube with two soldered wires) right behind. This sensor gives pulses for each 'cutting edge' when they pass by. Based on those pulses the deck control logic knows whether the tape is still moving or blocked (or cut).

 

And by the way, the black cube Ralph-Marcus mentions is the bulb housing for the cassette spool back-lighting! But methinks he was kidding Stick out tongue

The mystery remains...Wink

I missed that.
Yes, it's the lamp socket. And the lamp is missing.

Martin

chartz
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chartz replied on Fri, Feb 27 2015 1:09 PM

In English: brake arm for left-hand turntable Wink

Jacques

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Orava replied on Fri, Feb 27 2015 1:24 PM

Aaaa, didn't dig that deep, Lamp were in shop with me to ensure it is T-5.

Weren't those ancient engineers ingenious SurpriseSmile

 

 blah-blah and photographs as needed

Ricardo
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Ricardo replied on Sat, Feb 28 2015 11:53 AM

Cleaning off the old tape on the glass panels.. Tot soapy water , patience and a soft washcloth.

 

Orava
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Orava replied on Mon, Mar 2 2015 7:41 AM

Downgrading (mechanically) ps caps.

 

 blah-blah and photographs as needed

chartz
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chartz replied on Mon, Mar 2 2015 9:38 AM

Most surprisingly, I found these caps to be still fine after all this time. But like you, and for peace of mind, I prefer renewing them. When you try to open them, you soon understand why they are still okay: the seal is extremely sturdy, when you compare to modern electrolytics.

Jacques

Menahem Yachad
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But even so, the newer caps (if good quality) do a much better job of damping the residual AC ripple, than the old caps.

See the ripple comparison here, about 1/3 down the page

Click here

Ricardo
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Ricardo replied on Mon, Mar 2 2015 11:04 AM

The panel are reattached. The way I do this is I use a silicone adhesive. I put a thin bead on the plastic frame the place it on the glass. Give it a couple minutes to "set" then I install and fasten in to place.

I then power up and start testing the touch functions. All worked properly in this case.

While i had the machine opened up I cleaned the CD lens using a moistened cotton swab as well as cleaning the tape heads. The seller had sent the original 75ohm FM plug so I rigged a "proper" antennae. She also stated the Beocenter had not been used in several years and only occasionally since 2000. Without an antennae it had difficulty pulling station. With the antennae it now works much better

At first the CD refuse to play, then after a couple attempts using different CD's It was able to pull track lists and play a bit. It was about the 5th CD test when it "kicked in" and began normal play. It has not failed since.

The tape will play for about 1 second then quits, Little movement on the left capstan and none on the right. I am guessing the belt or belts are shot.It does not fast forward or reverse and all.. There is some simple way of determining whether the deck uses one belt or two. but i forget. some number maybe on the tape head or something like that.

Later I connect up a Beogram 3300 to test datalink functions for the turntable and it worked fine. The little RL35 that it came with also worked.

 

Orava
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Orava replied on Mon, Mar 2 2015 11:20 AM

chartz:

Most surprisingly, I found these caps to be still fine after all this time. But like you, and for peace of mind, I prefer renewing them. When you try to open them, you soon understand why they are still okay: the seal is extremely sturdy, when you compare to modern electrolytics.

Menahem Yachad:

But even so, the newer caps (if good quality) do a much better job of damping the residual AC ripple, than the old caps.

See the ripple comparison here, about 1/3 down the page

Click here

Any toughts about bypass caps? ~470nf?

 

 blah-blah and photographs as needed

Menahem Yachad
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On old style analog, I wouldn't bother.

I start thinking about bypass caps like those, only on fast clock speed circuits, like a CD.

But those are my thoughts only - you might try an experiment, while scoping the signal, and see what you get.

I'm very much a skeptic - if I can't see a difference in the waveform, or really and truly hear a better sound, nobody is going to convince me that some snake oil is worth buying.

On the other hand, I'll blindly trust a more expensive manufacturer with a proven track record (Vishay, Wima, Nichicon, Panasonic), over a cheaper fly-by-night Chinese garage operator, who mislabels components to make a few more cents.

Orava
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Orava replied on Tue, Mar 3 2015 6:58 AM

Menahem Yachad:

On old style analog, I wouldn't bother.

I start thinking about bypass caps like those, only on fast clock speed circuits, like a CD.

But those are my thoughts only - you might try an experiment, while scoping the signal, and see what you get.

I'm very much a skeptic - if I can't see a difference in the waveform, or really and truly hear a better sound, nobody is going to convince me that some snake oil is worth buying.

On the other hand, I'll blindly trust a more expensive manufacturer with a proven track record (Vishay, Wima, Nichicon, Panasonic), over a cheaper fly-by-night Chinese garage operator, who mislabels components to make a few more cents.

Probably right, on other hand, it is easy to solder smd chip between caps legs.... But maybe wont this time

I dont see what chinese have to do with these?

 blah-blah and photographs as needed

Ricardo
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Ricardo replied on Tue, Mar 3 2015 10:49 PM

Just completed - me and a helper spent about 4 days putting this together,

 

This is pat of what i do to support my habit.

 

Søren Mexico
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Ricardo:
Just completed - me and a helper spent about 4 days putting this together

As a German "Meister" mechanic, I must give you my compliments and declare, you did not learn that in Mexico Big Smile, however, if this were a apprentice exam work I would give some few minus points for the blue tube running over the white tubes, and for not sweeping the floor properly Laughing. Plus point I would give for the straight lines nearly everywhere except for the tube at the ?expansion?  tank, and for leaving the  copies of the manuals handy. As we have to finish and time is money, this is a master piece. My compliments.

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

Jeff
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Jeff replied on Wed, Mar 4 2015 2:53 AM

A very neat and tidy installation Ricardo. By the way, your avatar, is that from the old TV show UFO?

Jeff

I'm afraid I'm recovering from the BeoVirus. Sad

Ricardo
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The blue tubing is another contractors mess I merely had to work around it.

Lt Ellis at Moonbase part of Shado. thought she was a real hottie back then when I was 10.

 

One of the completed Cement Ponds I have been involved building over the years. This one was from 2004.

 


Søren Mexico
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Ricardo:
One of the completed Cement Ponds I have been involved building over the years. This one was from 2004.

Now I see the whole picture, what can i say more than wow wow.

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

Ricardo
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Ricardo replied on Wed, Mar 4 2015 5:49 AM

Søren Mexico:

Ricardo:
One of the completed Cement Ponds I have been involved building over the years. This one was from 2004.

Now I see the whole picture, what can i say more than wow wow.

Sadly it was one of the last  of the hard switch pools. I waste a lot of my time dealing with this crap now. Buggie and user unfriendly and mostly Wifi incompatible bunch of crap sold for a fortune but made with some of the cheapest materials.

Orava
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Orava replied on Thu, Mar 19 2015 5:43 PM

Orava:


Oh yes, this really is a bit nightmare. Old fragile wires, lots of mechanics, springs, washers, rods.....

Bulbs changed, some of wont turn comletly off. Keys ok, lend left end from other machine. Windign ok, play not, like not enough power... Lost locking washer from end of reelrod (no hope to get ONE from this country nowdays)...

Uh, to be continued some other day.

 blah-blah and photographs as needed

Rich
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Rich replied on Fri, Mar 20 2015 12:16 AM
I feel for you. I gave up on mine and sent it to someone with more skill and patience. Successfully changing belts on a 3300 made me think I could tackle one of these.

I was wrong.


chartz
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chartz replied on Fri, Mar 20 2015 8:21 AM

Rich:
I feel for you. I gave up on mine and sent it to someone with more skill and patience. Successfully changing belts on a 3300 made me think I could tackle one of these.I was wrong.

I remember Rich!

Those can be fixed, but it is true they are a bit daunting. Our friend Rudy (Beolover) has now very complete instructions on his Beoblog.

My favourite deck.

Jacques

Rich
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Rich replied on Fri, Mar 20 2015 4:32 PM

chartz:

Rich:
I feel for you. I gave up on mine and sent it to someone with more skill and patience. Successfully changing belts on a 3300 made me think I could tackle one of these.I was wrong.

I remember Rich!

Those can be fixed, but it is true they are a bit daunting. Our friend Rudy (Beolover) has now very complete instructions on his Beoblog.

My favourite deck.

That was a fun thread.

Until it wasn't!


Ricardo
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Ricardo replied on Sat, Mar 21 2015 2:08 AM

Rich:

chartz:

Rich:
I feel for you. I gave up on mine and sent it to someone with more skill and patience. Successfully changing belts on a 3300 made me think I could tackle one of these.I was wrong.

I remember Rich!

Those can be fixed, but it is true they are a bit daunting. Our friend Rudy (Beolover) has now very complete instructions on his Beoblog.

My favourite deck.

That was a fun thread.

Until it wasn't!

 

Me - never,  ever , again. i have done four players plus a couple becenters. Once they were all fixed up and working correctly. they were put in a closet never to be used again. Complete waste of time and money.. The only deck in service is my Beocord 5000. I play one or two of my five remaining tapes every couple of months.

My poor 5500 just sits unattended and unserviced. But as they say, "One must complete the set".  I have completed the set.

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Beolover replied on Sat, Mar 21 2015 1:12 PM

Hi Guys,

Don't give up so quickly! Cassettes are making a comeback like vinyl did a few years back! Nothing beats nostalgia....;-). Rebuilding a 5000 is a bit like enjoying an expensive bottle of wine...it takes some time... I am still adjusting the last one I did here and there. Last night I gave it a bit less damping of the eject mechanism, for example, since the cassette would once in a while not eject fully...anyway, this mechanical stuff is a bit of an 'experiential science'.

I started organizing my blog posts a bit, and generated a separate page for the Beocord 5000, which lists all my related posts. I realized that this list of links represents a pretty comprehensive step-by-step guide how to do it. With regard to lost parts: Well, not great, but why not spend ~$30-50 on ebay and get a banged up unit? BTW: I always put the mechanisms on a terry cloth towel when I work on them. A convenient way to keep those alignment balls (definitely watch out for them when you take the head carrier off!) from going far...;-)

Good luck! I hope you will get your 5000s back together!

Rudy

 

http://beolover.blogspot.com

http://beolover.com

chartz
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chartz replied on Sat, Mar 21 2015 2:02 PM

I once looked for one of those balls for a whole afternoon Angry

It had located itself into a damaged joint - with just enough space for it - between two floor tiles.

Jacques

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Beolover replied on Sat, Mar 21 2015 5:37 PM

I am still grateful that you warned me about the balls when I did my first 5000! Still had to hunt for one, though...Smile

Rudy

http://beolover.blogspot.com

http://beolover.com

Beolover
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Beolover replied on Sun, Mar 22 2015 3:20 AM

Thanks! Much appreciated!

Rudy

PS.: I realized that the links to the posts on my Beocord 5000 page were all wrong. They should work now...

http://beolover.blogspot.com

http://beolover.com

Orava
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Orava replied on Sun, Mar 22 2015 9:22 AM

Obiously too long time sice working anykind of analog control logic. Two options, have to check internals of Swiss made motor, or feedeing circuitity.

 blah-blah and photographs as needed

Ricardo
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Ricardo replied on Sun, Mar 22 2015 12:21 PM

Beolover:

Thanks! Much appreciated!

Rudy

PS.: I realized that the links to the posts on my Beocord 5000 page were all wrong. They should work now...

Beolover,

I have really enjoyed reading some of your blog post regarding the Beogram 400x. very informative. Thanks

Søren Mexico
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I have my lovely BM 2400 on the bench. It has been playing good for about 3 years, here the old thread.

The BM 2400 has not been used for about 6 months, Friday I connected it, it played good for about 3 minutes and then shut down totally, no bad sound, no smell, nothing, it just stopped working, no standby. Today I opened it, checking the fuses, OK, checking the voltages from the toroidal transformer I got 129 VAC in, secondary 25 VAC and 18 VAC, After the rectifier (D50) for the 15 VDC supply nothing, with the 15 VDC the RL1 should be activated and give the 25 VAC to the OD1 rectifier, the OD1 is supposed to give 31 VDC to the main feed, 18 VAC to D50 should be enough to give 15 VDC but 25 VAC to OD1 is in my opinion very low for the 31 VDC feed. Do I have a bad transformer ???

I desoldered the D50, and a diode test shows OK

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

Rich
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Rich replied on Mon, Mar 23 2015 5:25 PM

Ricardo:

Me - never,  ever , again. i have done four players plus a couple becenters. Once they were all fixed up and working correctly. they were put in a closet never to be used again. Complete waste of time and money.. The only deck in service is my Beocord 5000. I play one or two of my five remaining tapes every couple of months.

My poor 5500 just sits unattended and unserviced. But as they say, "One must complete the set".  I have completed the set.

I have a BC8004 that sits in the garage unused, but I have 6 other decks that get quite a bit of use.  The BC2400 in the garage gets used all the time.  In the 80s and 90s I didn't own a single "prerecorded" cassette.  Now I have over one hundred.  You can find lots of 20+ cassettes for just a couple dollars here and there.  I recently bought the Led Zeppelin boxed set on cassette for less than $10.


Menahem Yachad
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If you've got anyVAC input to the bridge rectifier, then after the rectifier, you should have some DC. If not, change the rectifier! It may be failing under load.

Or C92 2200uF is shorting, and drawing the whole DC down.

25VAC is fine for +/-31VDC - remember that you've got big 5000uF caps, which ups the output voltage.

Do an experiment, and you'll see how - Isolate the rectifier output from the rest of the system, and measure VDC output (You'll see it's low). Then connect the 2 5000uF caps, and measure VDC (You'll see it rise).  Then load up the rest of the circuit normally, and measure the rectifier output again (You'll see it drop slightly).

I would use 6800uF on the replacement. 

Menahem

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