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Beogram 400x projects

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Ben_S
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Ben_S replied on Sat, May 23 2015 8:39 AM

No black model originally. I have noticed the different sizes myself before, only small differences but they are important!

Ben

Søren Mexico
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sonavor:

Søren Mexico:

When gluing wood to metal (steel) or plastic I use Gorilla glue white the contact glues are messier to work with and difficult to apply evenly



How long of a working time does it give? I think I want something slow drying so I have time to adjust clamps until the miter joints all align perfectly.

 

about 10 min.

 

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

sonavor
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sonavor replied on Sat, May 23 2015 10:40 AM

Okay, I will check Gorilla glue out. I have most of the old glue off the parts so later today I will head to the store and look over the glues. I have several epoxies and super glues at home already but it sounds like the Gorilla glue will work good for this. I'll have to dig out some scrap pieces to test it with first. Thanks for the tip.

sonavor
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Yesterday I tested out several glues with some scrap metal and wood. The Gorilla glue did appear to work the best in the shortest amount of time. I tried some DAP, E6000 and Liquid Nails as well. They might work but take a much longer time to cure (up to 72 hours). I ended up going with the Gorilla glue. It is the trickiest to work with however.  The glue foams as it dries and expands three to four times so you have to really be careful where you apply it. With all of the glues I tested, I was able to pull the metal away from the wood after two hours of drying time.

With all of the trim parts cleaned off good, I started on the new trim for the Beogram last night.  I decided to start with the right side metal frame and the right trim piece.  Then this morning, I glued the front part of the trim to that metal frame. The top part of the picture here shows the right side gluing and clamping. I also clamped on the front trim piece for that step to make sure the corner aligned. The bottom part of the picture shows the gluing of the front piece. So I am half way through with the trim repair. Hopefully the second half will go as smoothly.


Søren Mexico
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You choose the wrong Gorilla glue type, I mentioned Gorilla glue white this is a not expanding type and sets within 10 min. cures in couple of hours. Gorilla glue white is not a normal wood glue but made to glue different materials to each other

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

sonavor
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sonavor replied on Sun, May 24 2015 10:43 PM

Søren Mexico:

You choose the wrong Gorilla glue type, I mentioned Gorilla glue white this is a not expanding type and sets within 10 min. cures in couple of hours. Gorilla glue white is not a normal wood glue but made to glue different materials to each other

Okay, thanks for clarifying. The first side seems like it is securely in place and I didn't have any foamy mess. For the second side I'll switch to the other type.

Søren Mexico
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The expanding type is good for uneven objects, I repaired  a couple of speaker box corners with it, and it glues nearly everything

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

sonavor
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I checked my test glue samples and I like the results now for the E-6000 glue. It is clear and has a 10 minutes working time before it becomes like tacky glue. The nice thing about it is, as it is drying, any excess easily peals away. On my test sample I glued a steel bracket to a pine board. Now that it has completely cured, the bracket is securely fastened. So I have started on the second frame piece now. I just did the front trim panel and have it all clamped down good. I had to enlist the help of an old bucket. I'll give that a few hours to cure, then do the last side piece around 10 PM tonight. Hopefully, by tomorrow I'll be able to install the trim on the Beogram.


sonavor
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The left side frame and trim pieces were a bear to get glued together correctly. I can't say I am 100% pleased with the result but I think it still looks way better than the trim it came with. I finally had to resort to some of the foamy Gorilla glue for the corner.


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It took until 2 PM today before I felt the wood trim panels were cured enough to install. The original trim mounting tabs were plastic and some of them were cracked so I decided to take metal ones off one of my Beogram 4002 Type 5503 turntables as this Beogram 4000 will become one of my main turntables.


sonavor
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The Beogram 4000 trim repairs and installation took longer and was more difficult than the tonearm repair. After I installed the trim piece, I had to go through the floating chassis adjustment procedure to get the platter level with the turntable deck.  This can take quite a while and I wasn't able to get the platter perfectly centered in the aluminum trim piece as I would like. You can watch a nice video of how to make the adjustments at Beolover's blog.
Here is the Beogram ready to put to work. It isn't pristine but I never expected to find one of these turntables and I am thankful it works now.  I am actually happy with all of the adjustments and feel this turntable is able to perform up to its ability.


sonavor
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The dust cover looks great in this picture. However, it actually has a number of bad scratches and I will have to return to fix it some time in the future.  I haven't yet attempted to restore these dust covers so I don't want to practice on this one.  I have a 4004 dust cover that is broken I can use as a practice piece. For now, I am going to start using this Beogram and see if any re-adjustments need to be made.  I should have a replacement lamp for the strobe in about a week so I'll have to open the turntable back up to install that.


sonavor
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This might be sacrilege but I decided to start my Beogram 4000's service out in a mixed system. I paired it with a Yamaha C-80 preamp, MX-1000 power amp and a pair of NS-1000 monitors. The sound with the Beogram spinning a new copy of Tom Petty is excellent. Eventually I may move the Beogram to a system with a Beomaster 4400, an 1970's era Beocord 5000 and a pair of MS-100 speakers but for now I like it with this system.


sonavor
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Here is a closer picture of the Beogram 4000 doing what it does best. When it comes to turntables, I have been biased towards Bang & Olufsen tangential tracking turntables since I first saw a Beogram 4002 in 1976. I had no idea that there was a Beogram 4000 in 1972. It is quite amazing to see and work with this fantastic designed machine. Thank you Mister Jensen.


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Beolover replied on Tue, May 26 2015 9:05 PM

Awesome job!! I am very happy that this came out so well in the end!

BTW: In 1972 I had a vintage Grundig mono reel-to-reel from my dad...I did not know B&O existed!...;-)

Rudy

 

http://beolover.blogspot.com

http://beolover.com

sonavor
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sonavor replied on Wed, May 27 2015 12:45 AM

Beolover:

Awesome job!! I am very happy that this came out so well in the end!

BTW: In 1972 I had a vintage Grundig mono reel-to-reel from my dad...I did not know B&O existed!...;-)

Rudy

 

Thanks Rudy! I am quite happy with it too. I was starting college in 1972 and my turntable was a big Elac Miracord 50H. It was a nice, rugged turntable with a good motor. However, once I discovered the Beogram 4002, I had to make the change. In the last couple years I picked up a couple of Elac decks (50H and 770H) for nostalgia purposes.  I was thinking I would play them occasionally but I find myself just focusing on vintage Beograms now.

With everything I learned on the Beogram 4000, I am going to re-visit the Beogram 4002, Type 5503 that I started this thread with and fine tune some of the adjustments. The 4002 is also in need of a dust cover make-over.

I think this thread should provide a lot of good information to those out there that are looking into what is involved in a 400x restoration. I will also post more Beogram 400x information as I keep my working decks maintained and as I repair new ones. My next B&O turntable project looks to be a Beogram 8000 so that will be a new thread.

chartz
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chartz replied on Wed, May 27 2015 12:54 PM

You both did amazing jobs, Rudy and John. As you say in the US of A, kudos! Smile

Jacques

sonavor
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I received a wonderful shipment from Frede today. A Beogram 4000 strobe assembly.
Many thanks Frede!

 


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I must be doing something wrong and I've been looking at the problem for so long I just can't see it.
With the new strobe assembly connected to the strobe control wires, I measure the expected, 120 V, 60 Hz AC voltage when the turntable "On" button is pressed but there is no light from the strobe lamp. Same as my other two lamps I have tried.


sonavor
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When the "Off" button is pressed and the tonearm assembly returns to rest, the voltage across the strobe wires drops to a near zero AC voltage as expected. To me, everything looks like it is working correctly but I still don't get any illumination of the strobe lamp. It isn't necessary to operate and use the Beogram but I still want to get it functioning. Before I give up and go with an LED solution, does anyone have any suggestions of what to try? 


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hamacbleu replied on Sat, May 30 2015 4:51 AM

On mine, it takes sometimes more than 30 sec before it lights up. The 1st strobe I had was not working: i was measuring continuity between both ends of the strobe (really weird, as both metal plate inside the glass didnt seem to touch at all) do you measure infinite resistance between both ends of the disconnected lamp?

Guillaume

(Congrats on your impressive work by the way..)

sonavor
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Thanks Guillaume. I appreciate the compliment and your suggestion. Using the removed lamp holder, I went back to my bench and connected it up to my variac (through a 27 kohm resistor). I also do not get any lamp output.  I have three of the neon lamps now and none work for me.  Measuring the resistance between the disconnected lamp terminals, all of them measure infinite resistance. When the lamp was in the holder I also measured the voltage with my DMM probes right on the lamp terminals to verify the AC voltage was there.
Here is a picture of my bench test.


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sonavor replied on Sat, May 30 2015 6:36 AM

Guillaume, is your Beogram 4000 running on 110 - 130 VAC, 60 Hz ?  If it is and if you don't mind, can you measure the AC voltage across your strobe lamp when it is on?  No problem if you don't want to do that.  I will understand completely.

John

chartz
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chartz replied on Sat, May 30 2015 7:40 AM

Yet another one and it doesn't work? Very hard luck indeed!

Jacques

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hamacbleu replied on Sat, May 30 2015 11:55 AM

sonavor:

Guillaume, is your Beogram 4000 running on 110 - 130 VAC, 60 Hz ?  If it is and if you don't mind, can you measure the AC voltage across your strobe lamp when it is on?  No problem if you don't want to do that.  I will understand completely.

John

Hi John, 

No problem, at all! In fact, I remembered having been puzzled at the values I got the 1st time and I was really curious about what I would have now it works.

I have about 132V AC, strobe on..

now I really wonder How could that be since our main is in the range of 117-118 V 60hz AC... And these are the values I expected since it's a 1-1 thing! Now I'm still puzzled... how can I have a higher AC voltage than the main??

The switch under is set to 130 though. This time, the strobe lighted up as soon as I pressed the 33 button.

I really hope you'll get it working. I clearly understand that you want it to work since it's an integral part of the 4000 experience, (even though it's somewhat useless... on mine, I even let it on the 50hz position since the effect is much more brighter there!)

Guillaume

chartz
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chartz replied on Sat, May 30 2015 1:12 PM

hamacbleu:
Now I'm still puzzled... how can I have a higher AC voltage than the main??

Guillaume, it is possible to augment the AC voltage! When valve equipment ruled, this was even the norm, with transformer outlets producing 2X300 V or sometimes more at their secondary windings.

A transformer is reversible too. No magic here, the number of turns gives what comes out!

So there are step-up transformers and step-down ones. 

 

Jacques

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hamacbleu replied on Sat, May 30 2015 1:41 PM

Thanks Jacques... Kind of a relief.. When it comes to DC I understands things here and there, but, sadly, without the global picture. As for AC, i'm somewhat clueless!

So, do I understand that in theory, the voltage at the strobe socket should "ideally" be the same as the Main ? Does the neon bulb as an effect on this voltage or it's only related to the windings of the primary and secondary of the transformer?

Guillaume

 

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chartz replied on Sat, May 30 2015 1:50 PM

hamacbleu:

So, do I understand that in theory, the voltage at the strobe socket should "ideally" be the same as the Main ?

Not very important. 

hamacbleu:

 Does the neon bulb as an effect on this voltage or it's only related to the windings of the primary and secondary of the transformer?

No effect whatsoever. Same neon as found in cheap Chinese power strip switches! Most turntables had their strobe lights directly connected to the AC power source.

Jacques

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hamacbleu replied on Sat, May 30 2015 2:23 PM

Thanks Jacques for your answers,

So in John's case it means that the bulbs are clearly defective. But 3 in a row is particular. Perhaps the value of the current that passes through them could be modified by altering the value of the resistance? Sometimes, mine does not light up until, what seems to me, a fairly long time. I noticed that the same happens when they change the neon in the ceiling at work.

chartz
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chartz replied on Sat, May 30 2015 2:25 PM

Exactly. They have a limited lifespan.

Jacques

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sonavor replied on Sat, May 30 2015 6:20 PM

I discovered that the neon lamp is the same as used in Thorens TD125 turntables. There is someone selling a new, replacement lamp for $30 (+ $20 shipping) on ebay.  Way too much. I think I will pursue a replacement LED strobe circuit . If the neon lamps are no longer made then it is just a matter of time before they go out anyway.

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hamacbleu replied on Sat, May 30 2015 6:56 PM

It turns out for dual too, and Telefunken

Check this out:

dualfred.de

search for lamp... This guy seems to make replacement strobe with led.

I don't know a thing about this german shop though...

Guillaume

sonavor
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sonavor replied on Sat, May 30 2015 7:12 PM

hamacbleu:

It turns out for dual too, and Telefunken

Check this out:

dualfred.de

search for lamp... This guy seems to make replacement strobe with led.

I don't know a thing about this german shop though...

Guillaume

Very interesting Guillaume. Definitely worth checking out. I'll try and contact them and inquire about my situation. I am picking up a step up/down transformer next week so I can try 220V on my existing lamps. I still want to verify my lower voltage isn't the problem because it seems weird that all three of my lamps would be defective.

John

sonavor
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sonavor replied on Sat, May 30 2015 11:06 PM

I did some more reading on the neon lamps. They act as an open circuit until they reach a level where they discharge. At that point they act as a resistor. Since I always measure my line voltage across the lamp, my lamp must never be reaching the necessary voltage potential (and never flashes). Of course, it would also act that way if the lamp was defective but I still find it odd that all three lamps (from different sources) are bad.  I will know for sure when I get the step up transformer to test with. If my reasoning is correct, then when Guillaume measures 130V across his neon lamp, that is the voltage divided between the lamp resistance (as it flashes) and the 27K resistor and his transformer's secondary output. I am thinking the secondary transformer output for the strobe lamp is much higher than 130V. That will also mean I cannot replicate that voltage in my Beogram due to my original transformer being defective. The new toroid doesn't have a secondary voltage output for the strobe lamp because it would have made the toroid too large to fit in the chassis. My most sure solution might still be to build my own strobe using a diode bridge, load resistor & LED(s) routed through the strobe switch to the 10 VAC transformer secondary.  The voltage is much lower and would know the strobe is designed for that.

sonavor
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My step up/down transformer arrived today. With it, I am able to confirm what I thought...the strobe lamps are indeed good (2 out of the 3 anyway...one is bad).  The problem is that the strobe lamp minimum voltage to fire it is above the US line voltage. My line voltage is typically 125VAC, 60Hz.  I used my variac to dial up the voltage, through the transformer, until the neon lamp starts firing. I am also using the 27kohm resistor as the BG4000 uses.  It took 179VAC for the lamp to fire good.  That meant a voltage across the neon lamp of 142.5VAC as measured by my DMM.  So this is good.  It means my original transformer was really bad.  It didn't have enough voltage to accurately drive the platter motor and it wasn't providing the necessary step up voltage for the strobe. I had to sacrifice the voltage for the strobe in the new transformer because of space. I'm very glad I didn't try to squeeze in a 1:1 secondary for the strobe because it would have been a waste (wouldn't have worked at all). Now I can continue on and build a strobe replacement that will run off the 10VAC secondary.
Another bit of information - The other good neon lamp required a higher voltage of 184 VAC to operate.  For that lamp, the drop across the lamp was about 132 VAC which matches up with what Guillaume sees on his BG4000.


chartz
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chartz replied on Tue, Jun 2 2015 7:23 PM

Interesting. Live and learn, John!

LED it is then.

Jacques

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sonavor replied on Tue, Jun 2 2015 7:42 PM

chartz:

Interesting. Live and learn, John!

LED it is then.

With the neon lamps now firing, I can see what light color I have to match.

sonavor
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Just to clarify...
If you have a Beogram 4000 with a faulty transformer and want to replace it with the original, full functionality, the secondary transformer outputs need to be like what is in the picture below. The problem will be getting a transformer built with that functionality that will fit.  I was unable to find anyone that could repair my original BG4000 transformer (due to the epoxy) and I wasn't able to find a duplicate transformer reproduced. The toroid solution is a solid solution but does lose the secondary for the strobe lamp. Plus, my transformer is for a fixed input voltage (120-125VAC in my case).  It is still preferable than having a non-functional Beogram though.


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While spending the past week happily listening to the Beogram 4000, I have also been proto-typing an LED strobe for it.  The basic circuit looks like this (bottom circuit in the picture). I just temporarily gave the circuit components a designator of 5 but I haven't decided it I will use a small board like my prototypes or have a surface mount board made with the components that can (hopefully) fit in place of the original neon lamp.


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So far I have built two prototypes.  Both use red/green LEDs to allow mixing colors and both use trim pots until I can determine the final values.  The picture here shows the original neon lamp color and the adjusted LED.  The match is actually closer than the resulting picture shows but I will have to play with the color still and turn the red down a bit. The other prototype has two LEDs like the circuit diagram I previously posted.  I will have to determine whether I go with one or two LEDs in the final circuit. 
To test the prototype I used my variac to dial up 10 VAC into the bridge rectifier to simulate the 10 VAC secondary in the Beogram. I verified the LEDs are operating at 120 Hz as they need to in order to match the original neon lamp.


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