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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hi to all, I would like some help in reconstructing the mechanism of my beocord 8002, that has never (until yesterday) worked. I thought, at first, that the problem was really small (a missing spring for the play clutch, which was later found in the machine, see that thread: http://archivedforum2.beoworld.org/forums/p/1790/15141.aspx#15141 ) but it's worse than that.
Particularly, i'm left with a spring: I have no idea where it goes. I would also like to ask some questions about the functions of certain parts, as I don't understand their overall role. I will document all this with many photos. Thanks to all in advance for your precious help.
Please note that I achieved to make it play yesterday for the first time (intermittently) Fast forward always work (with difficulty or not) and rewind barely moves at all... and unfortunately, there is no sound output... (I'll come to that later: r2 resistor of pcb3 is burnt and capacitor 2 of the same pcb gets REALLY hot...)
1st mystery to solve: Here's the missing parts of the mechanism:
-I reglued the leaf spring with krazy glue (had no other choice, it holds surprisingly well though) and put back a small metal ball under it. The other leaf springs had lost their small balls, so i created some with solder drops: it works well. I have no ideas where the 2 other washers goes...
But most importantly, the spring... Checking the service manual, I may think that it goes somewhere here, but how? (12197) Note the small pin on the bracket 12199. Does it have a function?
And here are some photos of my mechanism with all their actual springs, in case someone would see where something's missing...
Thanks for your help, to be continued...
Clear washer goes on the capstan spindle after insertion to stop lubrication from creeping up the spindle. That is on the upside of the deck.
Metal washer looks like one of the three used for fastening the deck into the Beocord.
The plastic thing with the shiny leaf spring holds a tiny steel ball (that often goes missing). It can be glued back in its place on the main chassis, right in front of the erase head.
The spring goes from the protruding tab (the one you marked with the ?) to a small screw sitting at thefoot of the large black plastic stand that holds the pointy end of the triangular plate, covering the flywheel.In the photo this screw is just out of view behind the stand.
Martin
Thank you very much Martin! I would never guessed it...One problem solved!
...Now it rewinds and fastforwards. but play does not engage at all. The belts are dead, however, but since I was suspecting other problems, I wanted to clear up everything before putting new ones from you. I made the test of cutting about 1/2 a inch from them and glue them back to see if it makes any differences. and I also tried different diameter of rubber to see how it responds...One of the rubber, use to replace the small belt made the fastforward and rewind acting perfectly.. So the belts are definitely a problem.
However: what makes the play stay engaged or not? I don't understand the mechanic of it. Because if I manually press on the bottom section, towards the capstan, everything appears to turn correctly. When I picked up the spring for the play clutch from the bottom of the machine, it was completely destroyed. I manage to put it back but maybe it too tight for the clutch?: see below before and after:
Also, what is the purpose of the arm shown with the blue arrow? Because the way it appears to be mounted, it always seem to retain the left wheel. I understand that during playback such a feature can help retain the tape to the head, but when the rewind or fastforward is used, it's function is not clear....
Thank you!
The solder drops you used instead of steel balls will deform with time, buy a ball bearing, 607, 609 or something very small.
Pack the bearing in a rag, place the bearing upright on a vise or solid iron plate or concrete, hit it at the top, hard, with a 400 gram hammer, the outer ring will split, and from the rag you can now pick the balls, and have some spares for next time.
Before hitting with the hammer, make sure no fingers are in the hit area.
Collecting Vintage B&O is not a hobby, its a lifestyle.
Thanks Soren, great ideas... I was really wondering when i rebuilt the deck what I could use as a substitute for that. I'll do this if I manage to make it play right one day: after I put back everything in it's place, and testing with different kind of rubbers, the fastfoward and rewind acted the way they should. When play was pressed, however, the machine engaged and disengaged immediately.
I wondered if the belts where still the problem but at one point, an electrical failure occured: every lights of the machine were turned on (lights that I've never seen before) And the machine went into play mode and the mechanism was playing accurately!!! it stopped after 10 sec and went back to it's previous state. So from now on I think that the problem may be more an electrical one. I'm really an amateur in electronic, but after studying the schematic, I think that a failure in PCB4 might be the cause. Am I looking in the right place? And PCB3 might be the reason why there is no sound at all: C2 gets really hot and resistor R2 is burnt. I'll have to change this and maybe the other capacitors: there's not too many of them. Does anybody know what cause the solenoid to stay in place when play is hit? Thanks!
Replace those two 100/16 caps. They are notoriously bad.Of course, you should also replace the burned 47 ohm resistor.
And change the red cap next to the two 100/16 as well.
All these issues I had on my cassette Beocords of the 6000-800X-9000 series!
The 47 ohms resistor burns when the cap is shorted.
I glued the slider support (the plastic bonds just break) with Araldite two years ago in my BC9000 and it hasn't moved ever since.
The bigger issue with those mechs are the rubber tyres... they were tired (pun intended), ie slippery, on every machine I've worked on. I haven't found any sources yet.
Jacques
...Maybe this should have been in the workbench after all...
Today I took out my soldering iron:
I replaced the 100uF capacitor of pc3, along with it's 47 ohm resisor
Being there, I also replaced the other 100uF and two 470:
And, why not, a 47uF on PC4.... Then guess what????
Nothing...It behaves the same way. press play, engage, then stops immediately. Rewind and fastforward are perfect though...
I thought it was good for the junkyard. And pressed play fanatically in hope that something would happen. Then I saw 2 bars of green lights on the display for half a second, intermittently...I never saw those. I put headphones just to see ..And I heard!!! there was an output! for the first time probably in decades. (For half a second each time)
Please help me with that annoying autostop function! I dont understand how it works. Sometimes, the arm (the round thing with the rubber) doesnt stick to the turning plastic white wheel. Maybe that's what making it stop. Jacques, you're talking about tired rubber..maybe that's my case. Did you have the autostop function problem? Tomorrow, i'll try to make a small rubber ring to put around the plastic white wheel, just to give it thickness. Maybe it'll solve my problem. Anyway, I don't understand how the machine detect that there is no movement. Is it related with the tiny board fixed on the back of the transport?
Or easier: can the autostop be bypassed?
Thanks!!
Good work on the electronics!
I did not have the auto-stop malfunction problem, if that's that. Check on solenoid operation, and also that the brakes are correctly mounted, that the sliding tray goes fully to its end stop.
The problem with the rubber tyres is that they harden and lose their grip. The old "I will add a rubber layer from a bike's inner tube' won't do any good.
For a bit of laughter: http://www.terrysrubberrollers.com/mods.html
You can try to sand it slightly to remove the shiny surface and get to a grippier one, but even this will never replace a new tyre and get back to silent operation.
Also, I can clearly see that both white plastic wheels on the jockey assembly are cracked, not too good either as the wheels may slide (have slid) along the shaft.
Bon matin !
Très drôle!...
But this is probably what I was going to make. .. instead I reopen the mech and reajust the small wheel with a rubber under the bigger one. Now it turns without problem.
Something really funny happens when I disconnect from pc1 plug 21... this is when I have an output... At one point, it started to play accurately for 20 minutes with stop, fastforward and rewind! I was so overwhelmed that I made a video of it working to keep as a souvenir. I swap cassettes: I even had the time to plug it to the beomaster everything was fine. I thought I was dreaming.
However, during that time, the display showed number in fastforward.... Then it all came back to it's previous state, instead that now, my fastforward and rewind engage and disengage like the play button....
I might give up on that: maybe it's the microprocessor that believes that it's always at the end, or it believes that the stop button is always pressed.
Any thoughts? Is this a common fault?
I reckon that you have checked the solder joints at the connector bases as well as the continuity of the wires in between...
I agree with Jacques on the rubber parts.I can supply one of them as reproduction but there are a total of four and I'm still looking to finda good producer for the remaining.On most deck, a little sanding and cleaning of the rubber will bring the thing back nicely.
...No I haven't checked continuity...this is so an obvious task...I have so much to learn... Thanks Jacques
Yesterday, the record leaf spring has broken again: I don't know how many play/stop play/stop it has endured in one day... It's unusable now, so I closed everything indefinitely: that was enough for a tape deck: SO an obsolete thing.
Now i'm in the urge of opening it again...
This forum is so a nice thing... You're all so awesome and helpful. I'll take a small break of B&O for the next few days though, cause i'm gettin' a little obsessed with the machine.
I really love the design of that deck: the first time I saw an image of it was last spring. I really love the angles on the sides, the use of real wood, the aluminum buttons that reminds of a supercalculator of the time. This is so 80's. And I think it's so much more well proportioned than the Beomaster 8000 much sober than the beocord 9000 with it's black bar on the top of the left side... This, the beogram 4000-4004 and the beomaster 2400 (not 1900!) are my aesthetically favorite b&o pieces
You know, we all go through periods of depressing stalls when trying to repair things (perhaps not Tim or Martin!) so it's a good idea to have a break!
I for one often find answers in my sleep...
My favourite B&O devices have to be the old 60's 5000 series. My personal fantasy would be to find a Thorens Beogram 3000 but I am not holding my breath. I do use a 4000, but it's not the real turntable intended for that system!
Oh, and I love my Beomaster 8000 and Beocord 9000 Guillaume!
By the way I have a sister in Québec!
chartz:You know, we all go through periods of depressing stalls when trying to repair things (perhaps not Tim or Martin!) so it's a good idea to have a break!
Agree with Jacques, time off gives you new ideas and time to think it all over.
As for the rubber/plastic wheels, if I get examples and/or drawings I may be able to produce replicas.
Søren Mexico: As for the rubber/plastic wheels, if I get examples and/or drawings I may be able to produce replicas.
Very interesting Søren!
The only man I know of who can produce new rubber parts is Terry Witt in the USA.
http://www.terrysrubberrollers.com
chartz: The only man I know of who can produce new rubber parts is Terry Witt in the USA. http://www.terrysrubberrollers.com
Terry looks like a very good professional craftsman and with his experience, best thing is to let him do the job.
For me it will be a first time job, the fabrication of new wheel bases is no problem, the problem will be the vulcanizing, hardness and type of rubber.
I work daily with rubber rollers for printing machines and are working with several suppliers of the same, one of these would be my "vulcanizer" the grinding I will do myself. But it will be a first time for me for the rubber part.
Where I can offer help without problems, are new belt wheels and the like. I enjoy working with my lathe
chartz:I for one often find answers in my sleep...
haha! I dreamt of it too the next day!...yesterday I went back to it and repaired the leaf spring..And then closed everything back. Next time, I might try to change the caps on the microprocessor board.
I have to admit that the beomaster 8000 is really a beautiful piece, but it's really massive and heavy. I'm really lucky that mine was found only 3 km from here AND is in working condition. And if I would find a beocord 9000..I would probably take it!!! (It would have to be in working condition though because if i'm unable to service a 8002, i'm wondering what nightmare a 9000 is)
Happy holidays... lots of snow here in Québec! Bring your boots if you come to visit your sister!
hamacbleu:Happy holidays... lots of snow here in Québec! Bring your boots if you come to visit your sister!
Yes I know, she sent me a few pictures. Her school was closed!
As for the BC9000, it is quite nice to work on. I like the display assisted bias adjustments especially! Quite unique I think!
Send me the exact measurements of your rubber tires - in mm: ID - Inside Diameter, OD - Outside diameter, and Thickness.
There is a distributor here who has thousands of Konig rubber tires in stock - I may be able to find something. He had all the tires I needed to get my BeoCord 5000 in perfect shape again.
I can recommend Terry's Rubber rollers - he redid the idler tire of my BeoGram 1203. Perfectly.
Menahem
This would be nice!
****CONTEST****
The first who has a Beocord mech into pieces notes down the dimensions!
Back to Beocord!…
It's been almost one year I haven't touch this machine and I thought it was time to make something of it since all my B&O are (actually) functional.
First of all, I've got a brand new set of belts, so I dismantled everything, cleaned everything with rubbing alcohol and re-lubed everything.
By the way, here are the different dimensions I noted for the rubber rollers…(Jacques, I partially win your contest).. Trust me, I really wanted to give also the inside diameters, but in doing so, I realized that I would have destroyed everything…Sorry for that ... And thanks Menahem for your proposition, hope you can make something out of these information...
In dismantling the machine, I've found out that I might have reversed a screw last year, which was making the clutch not going up properly. Here's a top and below view of that said screw. This is how it is now. (If you compare with my photos of last year, you'll see that the opposite was done) It seems to me that it's more logical this way. I don't know however if i'm wrong or not or if something is missing (maybe a bigger washer was there before, but this seems ok, please correct me if I'm wrong)
When everything was reconstructed, the transport had a much more precise response for play, rewind and fast forward. However each function stops after about 1 sec. (and during that 1 sec, I have an audio output )
I knew that this would happen... I was back to that autostop function…This is the small IC responsible for that function:
Up until now, I always thought that the small metal bars were receiving a magnetic field of some sort from the solenoid and that this was making…. something…
A revelation came to me as I google searched for the small inscription on the small IC .. "DN838". It happens to be a small hall sensor that outputs a voltage depending of the orientation of a magnetic field… So the magnetic field has to be near that said component… (not the metal bars ). By looking closely, I realized that a round magnet was present at the bottom of the take-up reel. The IC seems to have a voltage input, a ground and 2 voltage outputs, depending of the pole of the magnetic field it is submitted. However, one of the voltage output, pin 1, does not seem to be used. So it seems to be an "on" and "off" thing.
I traced on the schematic were that signal was leading, and the various voltages I measured around the voltage regulator. that said signal returns to the power supply board, then to the microprocessor board:
So If I take the voltage of this output were it leads on the microprocessor, should I have an alternate reading when I engage manually the tape transport and the take up reel is turning?
For now, I just have a stable 2.2V at this point when I do this…If my assumptions are right, then the hall sensor might be bad and could be the cause of the failure: the microprocessor sees that nothing is turning, so it instructs the machine to stop...
Any thought or correction of my assumptions would be appreciated..
Thanks to all for your help!
(By the way, I replaced each and every red and black Roe capacitors present on that machine..)
Guillaume
Hi Guillaume,
Rings a bell!
http://archivedarchivedforum2.beoworld.org/forums/t/42286.aspx?PageIndex=3
Thanks Jacques!
I remember having seen that thread a few months ago... I never noticed the autostop part however... (but I clearly remember the photo of the technician, maybe that's why I lost my concentration
I haven't try however to press play and retain it... maybe it'll work if it operates the same way as the 5000. I also thought about just disconnecting the output of the hall sensor. This way the machine will not see any voltages and would work without autostop? Is it ok to do this?
I'll have to find a replacement part if that's really the problem...I don't know what would be the equivalent of that DN838 however, it seems to be an obsolete thing. Maybe Martin has them
By the way, I also acquired a beocord 5000 last month: it was my dream to create a system out of this, a beomaster 2400 and a beogram 4002. It is in perfect condition and came with schematics, manual, warranty cards and other goodies. Got it for a song.. Although this kind of machine is known to be unreliable, in fact, it's my 1st piece of B&O that is fully functional upon receiving it: I haven't touched anything.. plus the woodtrim is in perfect condition. What's not to love. I really love that design
Well, not having auto-stop will put a strain on tyres and belts, plus the motor won't like it either.
So my advice is to fix that.
The one I got on ePay was a different ref. too, but still it works fine. You can see the number if you have a look at my picture!
Yesterday I tried (just for testing purposes...) to disconnect the output (leg 3) of that hall sensor. Up to no avail: the machine reacts the same way even if no voltages is send to the microprocessor (IC8)... So, probably an alternate reading (on off on off etc..) has to appear to make it works...
Could it be that it does not receive enough voltages? (it actually receives 3V, I don't know/understand how much is it suppose to receive exactly). However, the voltage regulator related is sending the prescribed 24V.
...So It could also be that something in between that regulator and the sensor has failed..
Looking at the service manual for the same function, for the beocord 9000, I see that 12V should be at the hall input... The datasheet of the dn838 also seems to confirm that value....
I might have found a big culprit: a diode test between the base (positive lead) and the emitter (negative lead) of TR2 (on the power supply board) revealed an open circuit... I detached it from the board, it shows a forward current gain of 2... ewww!!!
The emitter of that transistor is directly linked to the hall sensor so that might explain a lot... It's a BC547B and it seems a relatively common component... more on that soon...
My second most wonderful B&O day!
TR2 was indeed the culprit, and the voltage that has to be at the input of the hall sensor is indeed 12. So it was fine after all..
I love those green bars! At last, I'm the proud owner of a fully working beolab 8000 system.... (14 months later...)
Thanks to everyone that helped!
(I'll need your help soon or later to make some minor and subtle adjustment on my beogram 8000, I already have an idea but I'd like to have some opinions on that...)
See you soon!
Nice work. I am part way to having a working 8000 system. I have my Beomaster 8000 close to being ready and previously I got my Beogram 8002 working. One set of MS-150 speakers are done so next for me is the cassette deck. I have Beocords - 8000, 8004 HX-Pro and a Beocord 9000. None of them work 100%. They are all project units. I guess my preference is to get the Beocord 9000 working. The 8004 actually does still work but it has problems with some display segments being out. It has been a while since I have checked the condition of the Beocord 8000. I will be studying your thread and some of the archived threads when I get ready to start. Hopefully I can duplicate your success.
-sonavor
Thanks Sonavor,
Please note however that my projects are far from perfection (when I compare to your Beomaster 8000 project... which is clearly aiming to a perfect unit) In my BM8000, I still have some things here and there to work out (like an intermittent distortion problem in the right channel that has mysteriously disapeared since three weeks).
And if you look at the photo of my working beocord, you'll see that some lights are missing behind the green bars. But my goal was to make it play so I'm more than happy for now...
Last year I didn't knew a thing about electronic... These B&O things triggered in me a real passion for the job of electronic technician... I deeply wanted to learn and to take some courses to get the required grade and found out on the net that the school that teaches is right down the street where I live!!!!
When I got there, they just told me that they did not teach that program since two years, claiming that now, when an electronic apparatus is not working, the people just throw them away...
What a shame...
So many people on this forum, like you, that posts their whole projects, and everyone that help me in a way or another with their parts, ideas or support, has become my teacher. And i'm really grateful of this. Also, the more I work on these things, the faster i'm able to solve the many failures surrounding them...
How did I miss this thread the first go around? Great work!
hamacbleu:So many people on this forum, like you, that posts their whole projects, and everyone that help me in a way or another with their parts, ideas or support, has become my teacher. And i'm really grateful of this. Also, the more I work on these things, the faster i'm able to solve the many failures surrounding them...
3 or 4 years ago I bought a BM 901 for 20 USD, as I´m Danish I know B&O, I bought Beosound 3000 and a pair of Beolab new in 2000 later I added a pair of Beolab 8000. But surfing Ebay I put in a bid on the 901, and got it. Now I had to deal with it, found this forum again, I was checking the forum 2002 before I bought my BL 8000. The 901 arrived I got it, with big help from the forum, working. And I got hooked, just like you, and wanted to learn more.
This forum is your best teacher, there are no stupid questions, everything gets answered, sometimes it take a couple of days, but the answers comes.
I went from 901, through BM 2400, BM 4000 and my until now best repair, a BM 4400, all of these only possible with the help of this forum. Check here what I did, there is a list with links to nearly all i did. Specially the BM 4400 thread describes how good this forum works, help from everywhere, when I was about to give in, the guys got me back on track, when things got heavy, a member I never heard of came in with good advise.
In between repairing I did my "homework", meaning: If I had to change a resistor, transistor or rectifier or any other component, I went to the internet and read about it, which types where, function, why, and what happens, a lot time spend, but worth it, if you really want to learn. You cant buy or learn experience, but some of the geeks here on the forum, makes their experience available to you. And use the search function, someone has had the same problem.
Not only in B&O matters does the forum works, there are so many members here with special knowledge far beyond B&O, I have several times mailed members with questions, not related to B&O, and been helped. You will find members with knowledge ranging from needles to steam engines, from pennies to millions, and I´m sure Rich can send a Rocket to the Mars, but he cant repair a cantilever, but he knows where.
What have learned is, never give up, there is help and an answer, somewhere, on this forum.
So get the tools and keep them coming (your threads I mean)
Thanks Søren!
Just went through your 4400 thread, really interesting ... I also spent SO much time last spring in my beomaster 8000, trying to make something out of it. I even changed every single transistors that could exist in one of the output amplifier.... just to find in the end that the cause was a stupid broken track!... Great and impressive job on your 4400... I'm particularly impressed with the work and the attention you gave to the wood veneer. In my opinion, vintage B&O are luxurious and a success of industrial design because of the use of noble materials like this. What a restoration!