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
Hi,
Ok, I get it now, thanks. Yes, that's what I was afraid of. There is nothing visible that would explain why the motor circuit was over stressed. But I will take a closer look.
Still did not figure out the strange AC voltage as like many of you pointed out, there should be no AC voltage after the rectifier. I unplugged the large connector and after that there can no longer be measured voltage to the audio circuits and the audio signal output terminals. But I guess that just shows that those are separate circuits powered and fed by that connector. The motor circuit still shows 12.5-14.9V AC voltage across the fuse (AC feed) and pretty much all terminals. So a short to the ground somewhere or failed rectifier?
Pekka T.
I believe that it is important to set the bar of what these machines require, so I post here the reply I sent to Pekka.
To restore the BG6000 or BG4000 to new condition, which will last 50 years trouble-free (and that is the ONLY way I work), costs about ???.
Consumers are completely naive when they believe that a 40-year-old turntable will last 50 more years with a minimum amount of work.
The description of "working" is foolish - your machine is like a 50-year-old Volkswagen Beetle (which has had a paint job, so it looks good, but) which has never been serviced - you put the key in, the engine starts, but it barely reaches speed, and cannot cannot make it past the first service-station. Yes, this Beetle works, but to what standard?
That is exactly YOUR machine, and ALL others, which are sold today as "working", which have NOT been correctly restored by a qualified technician, with a fanatical approach to detailed work.
There is a fortune of work involved in a correct and comprehensive overhaul of this machine - close to 600 parts are replaced or overhauled, and that is the ONLY correct way to do it.
I will not accept a project for work, if the customer believes that I am doing too much work.
To me, these machines are the Rolls-Royce of the audio world, and they deserve no less than (and will not function correctly without) the same level of attention to detail that a Silver Ghost would receive.
On the BG6000, there is ALSO the CD4 PCB which must be completely overhauled.
This is the work I do, beyond repairing any and all known damage:
On all PCB's
1. Replacement of all Electrolytic and Tantalum capacitors with Wima, Nichicon and Panasonic 105C long-life capacitors.
2. Replacement of all out-of-spec Carbon Power resistors with Vishay Power resistors
3. Replacement of all potentiometers with Bourns or Piher Cermet potentiometers.
4. Disassembly of all contact mechanisms (Keyboards, Relays, Switches) and polishing with non-abrasive cloth to new condition - no sandpaper is EVER used.
5. Disassembly of all motors and reoiling sintered bearings under vacuum, with 100% synthetic machine oil.
6. Disassembly and balancing of the tonearm and solenoid mechanisms.
7. Matching transistors in the appropriate parts of the circuit.
8. New Pulley wheels and Belts
9. Complete Calibration to factory specifications.
The only thing which is NOT included is a new cartridge, and repair of the transformer, if required.
Menahem Yachad: I believe that it is important to set the bar of what these machines require, so I post here the reply I sent to Pekka. To restore the BG6000 or BG4000 to new condition, which will last 50 years trouble-free (and that is the ONLY way I work), costs about ???. Consumers are completely naive when they believe that a 40-year-old turntable will last 50 more years with a minimum amount of work. The description of "working" is foolish - your machine is like a 50-year-old Volkswagen Beetle (which has had a paint job, so it looks good, but) which has never been serviced - you put the key in, the engine starts, but it barely reaches speed, and cannot cannot make it past the first service-station. Yes, this Beetle works, but to what standard? That is exactly YOUR machine, and ALL others, which are sold today as "working", which have NOT been correctly restored by a qualified technician, with a fanatical approach to detailed work. There is a fortune of work involved in a correct and comprehensive overhaul of this machine - close to 600 parts are replaced or overhauled, and that is the ONLY correct way to do it. I will not accept a project for work, if the customer believes that I am doing too much work. To me, these machines are the Rolls-Royce of the audio world, and they deserve no less than (and will not function correctly without) the same level of attention to detail that a Silver Ghost would receive. -SNIP-
-SNIP-
Hi Menahem,
Oh I disagree, it's much more complicated and delicate than that!
A Volkswagen Beetle? No, never! :D
But if you use that metaphor, yes I am fully aware of the scene. I am not a as naive and incompetent as some of you obviously think. I have successfully restored and driven much more complicated vintage cars across Europe, and often also at speeds exceeding 220km/h.
I am also more familiar with audio and video equipment, having worked as a product manager for a distributor of such products, but no, I am no electrician. But hobby electronics, RC stuff etc. I was doing already in the late 1970's. And I am fanatical about my restorations too. (2 E-types, 2 XJ's, 2 older Jaguars, a Volvo 1800S for my late brother, and helping out on many, many E-types, Aston Martins, a Rolls-Royce, and a few Maseratis, Lamborghinis and Ferraris)
I think you may have simply thought that based on my poor vocabulary or wrong terms being used in English, as I normally discuss these things (audio/video/electronics) only in Finnish. (this was my first post on beoworld BTW) and I probably had overreacted on the complexity of these devices and therefore did not question only getting 100V AC at the input fuses (faulty voltage selector) and not knowing which motors inside the Beogram were/are AC and which DC and now know that it can also vary on the vintage (my initial thought, as AC was infact used in HiFi equipment before semiconductors and computers took over.) Now I already know much more. Thank you for all the help.
I have serviced and sold mechanical parts for Rolls-Royce's and IMHO the B&O is far more advanced. :)
From the car world I would say more like Citroën! Now that's complex and advanced.Currently I have five vintage cars, the oldest one has an engine from 1948 on which I rebuilt the cylinder head last summer. But that's not complex, but the V12's I have (5.3L and 5.5L) are much more complex, even the one from 1972 that has electronic ignition which back then was Formula 1 technology. The newer ones (but still over 25 years old) do have FI, ECU's and more or less complex and delicate mechanical electrical systems, like self leveling suspension, ABS, speed and acceleration sensitive power steering, LSD, etc.
I understand the challenges and appreciate your knowledge and work and almost certainly wish to buy services from you as well as from other B&O speclialists, Mika, Alain, Rudy, etc. So I can assure you I am not a regular "consumer". Besides, how many consumers have you today looking for a CD-4 capable record player to hook up into a vintage analogue amplifier with vintage speakers? ;)
This was not the first junk yard sale item I just happened to come across. This was bought form a specialist dealer in Denmark (of all countries) together with a restored Beomaster 6000 Typ 2702 and a Beomaster 6000 Commander, which were all supposed to work together. I did this after many years of searching, considering, reading etc. It was not cheap but of course I though I was getting a good deal, like we all do.
I am not afraid of small challenges, nor am I afraid of mechanical work, having rebuilt a few engines and dozens and dozens of carburettors. :)And I have worked as a salesman of computers, software, digital video equipment, all for professional uses, so no consumers.(taking care of RMA's, ECU and ROM replacements, reprogramming etc.)
I'd like to progress just like with the cars, step by step, figuring things out, buying parts and services where it makes sense and repairing or remanufacturing things where it makes sense.
Respectfully,
Do you have any AC going to the rectifier?
Martin
Pekka,
A master of mechanical issues!
My point is simply - if someone has already (very successfully) walked the road down which you want to travel, does it not make sense to imitate him, so that you do not make unnecessary mistakes, wasting time, money and energy?
I get that you regard this collection as a treasure which you want to enjoy for a lifetime, and not some commodity.
So, is your objective to have?
1. A "functioning" unit, which to varying degrees, sometimes works, and sometimes doesn't, and has average sound, and which you will have to keep coming back to the forum again and again, for help?
2. A unit, which for all intents and purposes, is absolutely perfect, which you will operate confidently, while knowing that there will be absolutely zero surprises?
Many technicians work on the premise that 1 is acceptable, because it is an apparently excellent excuse that it is 40 years old, and therefore perfection is unobtainable.
For me, only 2 is acceptable, and nothing less. And certainly obtainable.
G-d bless you for your persistence - that I certainly respect!
Menahem
Dillen: Do you have any AC going to the rectifier? Martin
Nope, not really, and I am no electrician, more of a mechanic. So I will do as suggested. Haven't heard much of the dealer though, I have to try and get some other things (the Beomaster 6000 to start with) going and return to this. The transformer does not seem to work.
I will try to get a local B&O expert to take a look at things and possibly take out the transformer and two PCB's for complete restoration.I will try to find a better discussion thread for the Beomaster 6000 stuff.
Cheers,
Menahem Yachad: Pekka, A master of mechanical issues! -snip- So, is your objective to have? 1. A "functioning" unit, which to varying degrees, sometimes works, and sometimes doesn't, and has average sound, and which you will have to keep coming back to the forum again and again, for help? 2. A unit, which for all intents and purposes, is absolutely perfect, which you will operate confidently, while knowing that there will be absolutely zero surprises? Many technicians work on the premise that 1 is acceptable, because it is an apparently excellent excuse that it is 40 years old, and therefore perfection is unobtainable. For me, only 2 is acceptable, and nothing less. And certainly obtainable. G-d bless you for your persistence - that I certainly respect! Menahem
-snip-
No problem, thank you for explaining (in private) to me the the challenges with the 40+ year old components. I have a much better understanding why the capacitors should ALL be replaced with new high quality items. With the mechanic I used the metaphor of fuel lines. It is not a great idea to have dozens of small rubber hoses that may have dried out and are just waiting to crack or split and spray fuel around a vintage car's engine bay. So yes, I would always advice people to replace those. So now I know why the capacitors and many other components must be replaced, as well as potentiometers etc. as they would potentially put too much strain on the fragile semiconductors and other components that could fry the whole thing.
Having taken a closer look and measure a few things I can, I can verify that TR28 and TR29 are toasted, very likely also TR24, TR25 and possibly also TR26 and TR27. So why take the risk to just wait until the next one fails and the whole unit can again fry something else?
This may become a looooong project. Too bad, but I think live & learn. Oh, I bid on another (malfunctioning one) last night, but it went for too much for my liking, at this time at least. Lets see.
Ps. This might also inspire me to take a look at some of the 40+ year old semiconductors in some of the cars I have, maybe I should also have all old capacitors I can find in there replaced?