ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Well done Jacques you must have put a lot of hours into this.
But what will you do on a rainy day now ?
valve1: Well done Jacques you must have put a lot of hours into this. But what will you do on a rainy day now ?
Thanks!
Don't worry Eddie, I have a partially working Beomaster 8000 that was given to me after we met. Now anyone carrying the Beovirus knows this requires a lot of careful attention...
This particular example has display and tuner problems.
Jacques
A bit late, but I've found this!
One more...
I now have ordered a renovated idler rubber wheel.
The noise level was acceptable (hardly audible with music on), but irritating nonetheless. I have sent the old one to Josef Svalander in Sweden. It was recommended by Frede Kristensen of Classic Audio. Prices are reasonable. And the thingy doesn't have to travel to the US of A...
The problem with old rubber tyres is that they won't filter motor noise as well as new ones because the rubber becomes less supple, hence transmitting noise, amplified by the big, purposeful flywheel which resonates like a bell!
This is an ageing process that is irreversible, no matter what you try. Don't believe so-called miraculous recipes on the Internet, rejuvenating sprays, all this is more akin to snake oil than to any physical truth! And a hi-fi open-reel recorder is not a Xerox machine or a printer...
We'll see!
That said, the Beocord produces some beautiful sounds, only marred by motor noise!
One last thing I had to do was adjusting the auto-stop system, very sensitive to the type of tape you care to use. The tape would stop erratically at some point (always the same) because it had shed so much oxyde that it had become more transluscent at that very point, thus causing the thing to stop. But sensitivity is adjustable, and the sensing system can be disengaged easily from outside the deck.
chartz: That said, the Beocord produces some beautiful sounds, only marred by motor noise!
Clearly, Jacques, you're just not listening to the "beautiful sounds" at a loud enough volume!
Perhaps Rich!
I am still wondering why B&O used only one motor and all those rubber tyres and noisy felt gaskets when most others - with a few exceptions like Uher - used three motors.
The contemporary Revoxes were a little less dear and used three motors, and were completely silent in operation. They still are after 40+ years!
When playing, the right spool always makes some noise too, which is normal but slightly annoying!
chartz:I am still wondering why B&O used only one motor and all those rubber tyres and noisy felt gaskets
Hard to know unless you were there at the design phase. Perhaps it had planned to have 3 motors but the marketing/accounting people (even then) had their input.
Søren Mexico: Damn they found me, only one star I will have to renew my membership
Damn they found me, only one star I will have to renew my membership
Damn, me too.
Hi there, folks. I'm a newcomer to this wonderful site which I discovered via Google. I have a Beocord 2400 which I have owned from new, buying it (with help from my parents!) as a 21st Birthday present back in 1971.
I retired from my job as a broadcast television engineer last year, and having recently moved house, I've decided to do some renovation work on my tape deck. Although it is in "as new" condition, the transport drive is slipping badly and needs to be "warmed up" by leaving it running for an hour before use! It also struggles to rewind! I recall removing the top cover some years ago to try and clean up the drive pulleys, but had some difficulty in accessing them. The photos higher up this thread make it look easy, so I need to have another look!
Sometime in the early 80s, one of the playback heads went open-circuit. Unable to locate any Bogen heads, I bought one of the only type I could find, but it was useless - the inductance was completely wrong. Very fortunately I managed to locate a manufacturer who made a replacement head for me, measuring the inductance of the remaining winding in the original head. This proved to be completely satisfactory, and is still in use today.
I'm not sure how much use this will be to others though, as I doubt if that firm is still in business. I will have a search of my records though, and see if I can find the details.
If anyone has any hints or tips on how to stop the drive from slipping, I would be glad to hear them!
Regards,
--
Pete
Hi Pete,
Welcome to Beoworld!
Congratulations on your Beocord, BUT we do need photos here
Now, to your issue regarding slippery drive on the spools. The answer can be very simple, or more complicated.
The simple answer.
You need a circlip tool such as the one below to take the wheels out. Do be careful, those little rascals have a tendency to live their own lives.
What you can do is sand their edges slightly to remove the glazed part off the rubber. Here again, be careful not to be overoptimistic. Any bad manoeuvre can lead to irregularities, noise and wow (capstan idler). Use 300-grit sandpaper, glued to a small popsicle stick.
To do that, you'll need a lathe or perhaps a drilling machine (what I actually used myself).
Once this done, you should get enough grip to get the machine going.
The not-so-simple, less cost-effective answer. (but the best of course)
Take out all three rubber tyres and send them over here.
That's what I did for the main idler (important for speed regularity and noise), I just sanded the other two.
Then, there is a series of felt transmission gaskets underneath the spools that could need maintenance as well. The service manual is here - don't waste your time, you won't find it anywhere else! I know, I uploaded it
Hi Jacques, and thanks for the welcome! Yes, I was going to try roughening up the pulleys a little bit. We used to use pan scourers at work, which are a bit more gentle than sandpaper!
I've managed to clean a lot of gunge off the metal pulleys, which has helped a little bit. The rewind problem seems to be because the arm that transverses the deck just below the speed switch is sticking on its shaft. This means that the idler wheel is not being pulled into hard enough contact with the feed spool. I'm presently trying to remove the arm - I've got the circlip off, but the arm doesn't want to budge! I suspect congealed grease......!
I think it may be a similar problem with the capstan drive idler. If I use a plastic tool to increase the pressure on the idler, the speed instantly comes back to where it should be, but I haven't got around to looking for the pivot point for that yet!
I'll try and get some pix up tomorrow - I want to try and fix at least one of the problems before the family come home.....!
Cheers,
Yes of course! Hardened grease! Whatever you do, never be tempted to do anything to the springs, you know, like cutting them to augment traction
Those old stuck thingies can be pigs to take out of their shafts. The worst case has been a Sony CDP-101 drawer mechanism... It took me ages to remove and it was just old grease!
Good luck then, although Scotch Brite may not suffice to grind the rubber wheels!
Well, that went better than expected! I eventually managed to free the arm off by drip-feeding it WD-40 for an hour! It suddenly freed, so I gave it a good "wiggling" and then, when the WD-40 had evaporated, I put a few drops of light oil on it. Its now rewinding perfectly for the first time in 20 years!
The capstan drive responded to a thorough cleaning of the brass motor pulley and the capstan flywheel, but I did have to resort to sandpaper for the idler. It was too far gone for pan scourers!
Here it is on the bench:
Beocord_01 by pchristy65, on Flickr
Beocord_02 by pchristy65, on Flickr
And back working in its rightful place:
Beocord_03 by pchristy65, on Flickr
Beocord_04 by pchristy65, on Flickr
Yes, I know you shouldn't run it with the lid on, but it was only briefly, whilst I took the photos!
Whilst I was at it, I cleaned and de-magnetised the tape path. BTW, if ever you run out of iso-propyl alcohol, this makes a good substitute:
Cleaner by pchristy65, on Flickr
Just make sure you keep it away from anything plastic or rubber!!!
I now have two remaining issues: Firstly the tone controls are very noisy on the left hand channel only. They need a shot of switch cleaner, but I can't see how to access them. Has anybody got any ideas?
Secondly, I can't seem to get any input or output from the "line" socket. I've run out of inputs on my main amplifier, and I was hoping to "daisy-chain" a cassette deck through the Beocord, but I can't get it to work. Its a long time since I last tried to do this - is there something I have forgotten? I thought it should just work if I put the SonS fader up?
Pete, your Beocord looks stunning!
And it's got something mine unfortunately misses: the lid!
By the way, is the main wheel silent, or can you hear some droning? That's what pushed me to have my tyre renovated.
Thanks for the kind words, Jacques! It helps that I've owned it from new, looked after it, and it hasn't had a lot of use! However, its now beginning to try my patience!
Having got it all up and running, and re-installed it in our sitting room, this morning it decided to blow one of the 630mA fuses near the voltage selector! The only replacements I could get are fast-blow ones, and I think the original was a time-delay fuse. Its difficult to tell, but the other one is a slow fuse, so I guess this one should be as well. The fast fuses blow instantly - presumably from the surge of charging the electrolytics....
The deck is pretty quiet when playing - its actually noisier when it isn't doing anything! But the rewind is a bit noisy.
I have no idea why the fuse blew - the electrolytic capacitors (always a first point of call for this fault!) seem OK, and only one of the two fuses has gone. Perhaps it was just old age!
Anyway, I'm not going to be able to get replacements before Friday at the earliest, so it looks like my tape-deck is on hold until the New Year....
Happy New Year, folks!
Mmm... Are you sure the voltage selector is on the correct position? This would normally happen on the 110V position. I know, it happened to me while working on it, the selector turns very easily.
Hi Jacques,
No, the machine hadn't been touched from the previous night, when it was working perfectly! In fact, it had been on for about half-an-hour this morning before the fuse blew. I'd switched it off for a few minutes whilst I moved the cassette deck, and as soon as I powered it up again, it went PHUT!
I think it was just the combination of the current surge when I turned it on and an old fuse, but I won't know for sure until I get some time-delay fuses.....
Update: Since only one of the fuses was blowing, I temporarily replaced the un-blown one with a higher value fuse, and put the 630mA fuse in the one that was blowing. It promptly blew!
I think the first step must be to replace the big electrolytic capacitors associated with the power supply. Although these seem OK when tested with an ohm-meter, they could be breaking down under load. Electrolytics are well known for this, and the general advice is to replace them as they get older just as a precaution. Unfortunately with the New Year holidays upon us, it could be a week or so before I can source replacements.
Watch this space.........
Do test the diode bridge. A classic failure too.
That was next on my list!
First I have to figure out just where it is, and then how to get at it.......!
Right here, the module at the top with the two big caps: the diodes are on the other side. This comes out easily, but you do have to remove one of the preamplifier modules, and before that take the long bracket out. The module locking screws stay in place, do not remove them completely, just loosen them up slightly.
Hi Jacques, and thanks for the guide!
The module came out quite easily - I didn't need to remove the pre-amp module, and I only needed to slacken off the visible retaining screw and remove the two restraining the heat-sink. I was very surprised how easy it was - just like professional gear!
You were right - it is the bridge rectifier. One leg is s/c. I don't live near any component shops, and the only one I have with sufficient current capacity is completely the wrong shape. Its also in a metal case, so I'm reluctant to "bodge" it in.
However the board does seem to have been designed to allow for the fitting of individual diodes. Unfortunately, I only have one with a 3 amp rating (I have hundreds of 1 amp ones! ) so I've had to mail order some. I probably won't see them before Monday at the earliest.
Oh, well, at least I know what the problem is....!
Peter Christy: However the board does seem to have been designed to allow for the fitting of individual diodes.
However the board does seem to have been designed to allow for the fitting of individual diodes.
Happy New Year!
Yes, my module had the bridge replaced by ancient BY127 diodes, probably a long time ago then. Not a very handsome job I might say, definitely not mine! Plain 1N4007s should be fine, BY127 are 0.75 amp diodes.
I know the feeling about electronic part retailers, same here. But living in the country has other advantages, and I would never now live in a big city.
Wow! Its running OK with 0.75 amp diodes! I assumed that because there is a 3 amp fuse after the rectifier, it would need similarly rated diodes. I do have some very small 1.5 amp 300 piv diodes that would fit in easily! I discounted them because of the them "only" being 1.5 amp! I'll give them a try tomorrow.
If they blow, the higher rated ones should be here next week sometime........
Oh, and Happy New Year!
Jacques, thanks for the info on the diodes! I had a load of 1N4006, which I had discounted as I didn't think the current rating was high enough. But when you said you were running with 0.75 amp diodes, I thought it was worth a try. I fitted them this morning, and normal service has now been resumed!
The power board, with the original bridge rectifier:
PowerBoard_01 by pchristy65, on Flickr
With the rectifier removed, showing the holes for individual diodes:
PowerBoard_02 by pchristy65, on Flickr
And finally, with a set of 1N4006 in place. Note the sleeving on the upright one to avoid any possibility of a short!
PowerBoard_03 by pchristy65, on Flickr
The 3 amp diodes I've ordered are physically much larger. If I end up fitting them, I'll probably put two on the top of the board and two on the bottom. This should make for a neater installation, and reduce the opportunity for accidental shorts! But who knows? Maybe the 1N4006s will last for another 40 years!
Anyway, thanks for your help and encouragement! Much appreciated!
Good work!
I'm happy it's fixed. Methinks you won't need the other diodes at all, but peace of mind is important too... And once again, thanks for being here, hoping you will get and repair more B&O in the future!
Hi Peter welcome to the forum, good work and a very nice Beocord you have there, as Jacques I hope you will find more vintage B&O to repair and use. I have a Beocord 2000 Reel to Reel in working condition, but still with work to be done.
Collecting Vintage B&O is not a hobby, its a lifestyle.
Hi Soren, and thanks for the welcome! And to Jacques for providing encouragement and support!
Many years ago, between leaving school and getting a "proper" job, I worked for a local electrical shop as salesman and van-driver. They used to stock and sell B&O equipment, and also Dynatron - a British HiFi manufacturer of the time (sadly, no more!).
Whilst I was there, I bought a Dynatron stereo, and a few years later added the Beocord tape-deck to complement it. They worked well together. The reason for going for the Dynatron was because I could afford it - B&O gear was always very expensive here in the UK. However, when it came to choosing a tape deck, it was no contest! There was nothing to compare with it at the time, and my parents helped me with the purchase as a 21st Birthday present. I doubt I could have afforded it otherwise!
It has served me well over the years, and has even doubled up as a HiFi amplifier at times! I bought a pair of Kef Cadenza speakers many years ago, and these continue to provide a beautiful sound, whether driven from the Beocord or from my recently acquired Cambridge Audio amplifier.
Second hand B&O equipment rarely appears in the UK. But by strange coincidence, my son bought a Dynatron stereo - just like my old one - before Christmas! Only one channel was working, so he brought it down to me and we spent most of Christmas day fixing it. It was a *really* obscure fault on that, and if it hadn't been for a stroke of luck, I would never have found it! The amp uses a transistor wired as a diode in a temperature compensation arrangement - four devices being mounted on a common heatsink. The temperature compensator developed an internal short between the can and the device itself, so every time the heatsink was screwed to the chassis, it pulled the DC to the output transistors down to ground! Simply electrically isolating the heatsink from the chassis provided a complete cure!
I thought I was going to lose my mind finding that one!!!
Anyway, the tape deck is now behaving itself beautifully again, and my kids (and grand-kids!) are amazed at the quality of this "old" technology!
And what a pleasure the tape deck was to work on! I am used to the modular approach from my professional days, but what a joy to find domestic equipment built the same way! It certainly makes maintenance so much easier. The Dynatron was an absolute pig to work on.....!!!
Hi,
I had a close look at the service manual, and it turns out you will need more powerful diodes unless you don't use the internal amplifiers. The manual says that the BC2400 PSU needs to deliver more power because it has the amplifier modules. It makes sense.
I don't know how long my example has worked with the 1 amp diodes (probably a quarter of a century!) but for peace of mind I have replaced the BY diodes with a 4 amp diode bridge that goes exactly where the holes are. Reference is B80C3700-2200.
Then the 3A fuse does make sense, too.
Yes, that makes sense. I don't normally use the internal amp - except for headphones occasionally. I have noticed some hum on the headphone output, though not on the feed to the stereo, so its quite possible those diodes aren't quite up to it if you want to use the internal amp.
Thanks for the reference to the bridge - I had located that number, but no dimensions for it, so I wasn't sure if it would fit. Now all I have to do is find a UK supplier for it......!
Next time I have that board out, I'll probably replace the electrolytics as well. It makes sense to do it whilst its in pieces anyway!
You are very welcome. The hum on the 'phones output is probably down to the modules themselves, or cabling. I don't have any hum on mine, but one module had to be fixed (one bad transistor).
I've found UK suppliers for the bridge and also for the capacitors - isn't ebay wonderful!
One thing I still need to look at though is how to get at the tone controls. The crackle on them when they are moved is very loud, so they obviously need a good cleaning - but I can't see how to get at them!
Do you have any ideas?
In the BC 2000 I cleaned my potentiometers by getting in at the green arrows, the 2400 is different I think, but I am thinking about drilling off the rivets, clean and then assemble with small screws,
My thread is here
Peter Christy: One thing I still need to look at though is how to get at the tone controls. The crackle on them when they are moved is very loud, so they obviously need a good cleaning - but I can't see how to get at them!
Oh, they are quite difficult to get at. I did that when the Beocord was completely disassembled. To access them, you have to extract the chassis from the wooden housing I'm afraid (see page 1). Not for the faint hearted, but methinks you're not!
What Søren shows is a slider, which need to be cleaned too, but they are very difficult to reach, because cabling is so tight.
Oh, dear! Looks like a major dis-assemble! The sliders actually aren't too bad - you can get the nozzle of an aerosol cleaner under the plastic dust-flaps. A good squirt and plenty of wiggling does the trick without any need to strip the machine.
The tone controls are another matter altogether, it seems.....
Jasques.I wonder if you can teach me something about this.I took my BC2400 apart again this evening as the manouver arm had come off, and thought I should do some more work.The motor hum, I dont understand why the rubber tyres has anything to do with this , as the large motor hum is when the BC2400 is in idleling and none of the tyres are connected to the brass wheel. When ideling the motor is completly free of any mechanical connection...?I wonder this, because I have a BC1500 and that one in idling , is humming way to much.Could you teach me in this matter, as I obviously is missing some understanding It would be interesting to see what I can improve on the bc2400 and what I can do with the BC1500...Christian
My re-capped M75 are my precious diamonds.
There is another wheel underneath the others and that one is always in contact with the flywheel and the motor, as soon as power is applied.
The noise indicates that the rubber is too hard, thus transmitting motor droning - as little as there is -, as well as its own noise, to the large flywheel which amplifies all that like a bell... Simple eh?
Bottomline, replace the wheel to get rid of the noise.
Jacques is right! As soon as you turn the speed selector knob to any of the "on" positions, a rubber idler connects the brass motor wheel to the capstan flywheel. The capstan has a very large flywheel attached to it, and if it was only engaged when the "play" lever was moved, it would take a few seconds to spin up to speed. By having the capstan rotating all the time that the motor is "on", you get instant start up when the lever is moved.
The only time the capstan is not moving when the machine is powered is when you use the "PA" function, running the machine as an amplifier only, rather than a tape deck.
If you take the top deck cover off to reveal the drive mechanism, you can see all this happening.
Jasques,So was it that rubber flywheel that connects between the brass wheel and capstan wheel you sent to Sweden for remake ?I hope you tell us how the wheels turned out, as I am also interested in using there service.Christian