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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
This is my first post and I am almost completely new to BO! Having had some Tandberg and diverse Danish vintage equipment, I recently has become very interested in BO as well.I recently bought two Beomaster 1000's. One with white keys and one with black. Both need restoration. I really want to make these work. I am specially interested in the earlier version with germanium transistors. I opened the white one up today, and it seems a transistor was burned (marked AC128,3). There was black dust above it on the wood cabinet inside. I wonder if this is possible to replace..? Is there any hope?There may be other problems as well, I don't know yet. But this seems serious.Where do you find more rare spare parts for your vintage machines? How wonderful that there was a little envelope on the inside with schematics inside it!
Jacques
When I start a new project, I go to Martin (Dillen on this forum) first of all, he can provide most of whats needed, then onto E-bay as Chartz
Collecting Vintage B&O is not a hobby, its a lifestyle.
Thank you Chartz and Sören Mexico!I have located and ordered the transistor on ebay, you were right, many available. Now I need to change capacitors, still not sure about the best place to get high quality components (live in Sweden). I do hope very much I will be able to bring it back to life!Yesterday I disassembled it and took out the burned transistor. I don't know if you will find this interesting, or odd, but the fried transistor was made of plastic, while AC128s usually seem to have a metal cover (and all AC128's I found on ebay). I found that odd. It was also not soldered on the board but attached with wires and electrotaped (as insulation) and inserted in a heatsink like thing. However that is maybe standard. Could it be so that BO used a non standard component that subsequently failed..? I attach a photo.
That mess is definitely not standard.
Martin
Dillen: That mess is definitely not standard. Martin
A silicon transistor here? No way!
Good find, keep on and carefully check everything, someone was in there without knowing what he did
Thanks to you all!
I was right in thinking this was odd then.I'll post a follow up later.
The transistors bias resistor(s) could have been changed too in an attempt to compensate.Better check the whole circuit.
It seems nothing else has been changed. The resoldering of the AC128 is obvious though from beneath the board, so it has been exchanged.I am not sure what this transistor does.. Anyone knows?Attached is the schematics with it marked. And a photo of the inside of the cabinet..
Yes, it's part of the voltage regulator circuit.As a minimum, check also AC126-5 and AD149-5, resistor 906 and Zener 908.They all work closely together with AC128-3.
Most germanium transistors are housed in metal or glass.They typically die quietly. Only when really pushed they go with a nasty bang.
Thanks again for your answersI think indeed the zener diode 908 is bad. The resistors seem ok. AD149-5 seem ok.I need to buy a new zener. It is labeled ZF 9,1 on the schematics. I believe that is 9,1 volts, but does anyone know what else I need to know, watts?
An odd thing, or if is it me who misread, is that I get the impression that the schematic and the board plan do not completely match. There is a transistor AC126-5 in schematic, but I can't find it on the board plan, it seems this very transistor has become another AC128-3 here. I could of course pull it out to check what it says but I would prefer not to, it sits there so nicely in what I believe is a heatsink? (which I would probably destroy)I do wonder if they also mislabeled the fried AC128-3's emitter point on the board plan to be B instead of E..? This can be seen in my previous image if you are interested. Did BO make such mistakes? It must be me who is mistaken, but I can't figure this one out, where does the fried AC128-3's E connection go if not just to that point labeled B..I am so thankful for your advice!And this is so much fun! It is the first time I undertake something like this. It is such a lovely machine in how it is built.
Most will know that Beomaster 1000 came in white and grey key versions but it was in fact produced in 12-14 basic versions.Add to this several build series within each type, more than 30 for some types, and almost all had minor changes and revisions here and there.
I own 145 Beomaster 1000s (apprx 70 different - not counting woodsort variations) and my collection is far from complete, particularly whenit comes to export versions, but I've noticed minor differences even within the same build series and there were also some aftermarket revisions and service-related recommendations, that my or may not have been introduced.Not everything was well documented and the service manuals are merely covering the basic types.The included schematics would be the closest-to-correct reference but I wouldn't trust it blindly.
145 BM's, wow! The many variations, I see, I had an feeling this would be the case, but that many variations.. Makes the restoration all the more excitingMine came without speakers. I wonder what speakers they came with, and what speakers would be a good combination for them.. I just bought a pair of Beovox 2702's. Was originally looking for 1702's, but found these, newly restored and in a very good condition, like new. Not necessarily for combining with the BM1000, I was looking also for a BM 1001 and thought it could be a good combination.May I make a recommendation by the way? I bought these 2702 speakers here: https://www.anapeachloudspeakerrestoration.co.uk/The man behind this company, Andrew, is very nice to deal with and he often works with and restores BO speakers. I know he is working on a few new pair of BO speakers now.
The reason for the transistor confusion is that they have labeled one transistor wrong on the plan(not in the schematic).
Take a look here,the upper transistor is labeled correctly as AC128-3, but the lower wrongly has got the same number.That transistor should be AC126-5.
I have restored several BMs and never had a drawing that was exactly as the unit, as for the BM 1000 I found 3 different schematics, and non of them were for the one I have here (black keys)
As for speakers, the 2702 will do good, the speakers recommended for the BM 1000 was the Beovox 1000 and the BG was the BG 1000.
I have the BM and the BG 1000 using Beovox 1600 (wall speaker) until I find a pair of Beovox 1000
This said, I use my BM1000 and my BG1000/SP6 with S45-2 speakers with tremendous results.
Thanks for helping sorting out the transistor confusion. Rolf, that looks just like my plan.And thanks for your advice for speakers!This particular BM1000 is perhaps not in mint condition. But it deserves love nevertheless.The radio scale looks different from what I see on other white key 1000's on the net. Perhaps it's a very late white key version? (it has no model no label)I haven't figured out how to restore this part. Someone has taped the two parts of the scale, the thin front and the top section, together. There seems to have been some attachments at the corners, which now are broken off. Not sure how this was originally attached.
It's an exportmodel.Most units sold in Denmark had the names of danish radiostations printed on the dial, but theywouldn't make much sense elsewhere so the exportmodels only had frequency and channelnumbers.
Your Beomaster is missing the top half of the front center rail. It's broken off - common problem as the plastic becomes brittle with age.
Beovox 1000 was recommended for Beomaster 1000, though it really deserved better - it's a capable and wonderful sounding amplifier.Beovox 2702 will be fine. Even larger speakers would also be fine. Beovox 2400, 2600, 3000 etc.
Thanks Martin,Yes, I bought this in Sweden and I think it likely it was originally sold here.I do hope so much I will be able to make it sound. I am very curious about it's sound. Not sure I can pull this off by myself, but I will try.It looks like in this photo below (not mine, mine is even more broken). I have to fix this somehow. Thinking about it. Spares is probably not to think of. I have been thinking about visiting a hobby/model building store and see if they have something with which I can build up a frame for the transparent scale and have it attached.I also wonder if anyone could advise about the zener diode ZF 9.1. I must purchase a new one. Swedish Elfa has two variations, 9.1V 3W or 9.1V 5W that I consider. There are also 1.3W versions. The service manual says "the electronic protection circuit will operate at a current drain of approx 4 W".. Is that what I should base this decision on? A simple calculation gave 3W, but I am not sure about this. The Wattage shouldn't affect the performance of the diode in any other way I believe?
Googling ZF 9,1 tells us it's a 500mW diode.Use a 1,3W.
I did a quick calculation of the current through the zener diode and ended at about 8-9mA through the transistor and 10mA through the 1,8k resistor.
18mA in total,which gives a total power of about 170mW in the zener diode.
Rolf, so grateful for your advice! My calculations were way off, as suspected.Capacitors ordered from Mouser. Zener will be bought at Elfa.
Today I bought a second BM1000. For reference..Together with it came a pair of S45 speakers. They are in good condition cosmetically but the foam is bad and the need restoring. Do you want them? I give them away. I live in Stockholm Sweden. Space is getting scarce here. I hope they can come to a good home.This BM1000 was supposed to work. But before plugging it in I took a look inside. Someone has been tampering with this one as well. The on/off and the mono keys have switched place. Some screws were missing. The fastening point on the top of the cabinet was broken. The schematics are missing. But worst was the horrible dirt. Thick dust. But not "nice" dust that you can blow away, but sticky, greasy dust. After some preliminary cleaning with a brush and compressed air, I just had to plug it in to see what happened. And it worked! I have never heard a white keyed Beomaster 1000, but I had a feeling I would like the sound. And I do! Perhaps I have fallen in love.. Connecting it to a pair of Wharfedale Dentons (original early 70'ies or late 60'ies, newly restored) and a pair of Beovox 2702's (also newly restored) it really sings! I never made these speakers sing before like this. I even considered selling them because with my Tandberg equipment they just sound sad, dry, thin and hollow. How come this little receiver from 1969 can sound so "fat"? I love it!Some people say this receiver is not for everyone, that it has a special sound. What do you think? For me, who is allergic to modern "analytical", sterile sound with treble like sharp glass that cuts my ears.. perhaps this is just what I was looking for. And this even without me having changed one component (in spite of it's age, it sounds like this.. What if components would age like a good wine, to mellow..).I also have an unrestored black key BM1000 (not tested). I wonder how they differ in sound?Leads me to the next question for you gentlemen and gentlewomen better versed in electronics than me. My plan is to keep this one as untouched as possible, while I restore the other one totally (every capacitor will be changed, at least all the electrolytics, I think I have 55 pcs waiting..). But is there anything I might want to do to avoid a disaster? I think, maybe I should change the two 2200uf 25V capacitors that I believe drives the amplifier? And perhaps the 2200 50V power cap? To avoid speaker blowup in a capacitor meltdown scenario? Now, I dare not use it for everyday enjoyment. But I don't want to tamper with it too much.Oh, one more thing. Perhaps someone can advice, how to best clean away the oily greasy dust. See the photo. Isopropanyl alcohol, can it be used? Just bought some. Risk of destroying something, on the board for example? Perhaps you have better ideas. The greasy dust stuck on the transformer is specially bad and hard to remove.
I have always cleaned mainly with IPA, (isopropyl alcohol) but I always take the unit down to the nearly last screw, even if I have to desolder, on hard to clean metal parts sometimes I use acetone (careful may strip paint and destroy plastic), rusty pieces I leave overnight with a thin oil layer and then clean off with acetone ( if not clean, use abrasive pads), then a thin coat of oil.
Some of the guy guys here recommend Windex (window cleaner) some of them mix it with IPA some use it directly and then clean with IPA afterwards.
I have a bottle of Windex here and will try it out on my next object.
I have never heard a white key BM 1000 but the sound should be special because of the germanium TRs
Good luck
Even if the BM works, I would change all the electrolytic caps, here a pic from my BL 5000 of what happens when they start leaking
I wonder where does the grease go after applying IPA. I know the IPA evapourates, but the dirt..?So IPA does not destroy the board or any other components and can be applied liberally I understand.Cleaning it will be an interesting project too.I hope to keep this one as original as possible, until I can compare the two.. But I understand they both need new capacitors. Thinking of that, if you change all the capacitors, isn't there a risk that the original sound is changed? (However on the other hand, all the capacitors are old and may not perform optimally, I know). What performance can we expect with modern day components? Has anyone noticed differences with different types/makes of the exactly same spec components? For the first BM1000 I bought all new capacitors, mostly Nichicon Fine Gold type.
You wil have WASH to get the grease off, it will have to drain off with the IPA
The two 2200uF capacitors on the main board don't "drive" the amplifiers, they are the output series capacitors.The 2200uF filter capacitor in front of the transformer is a nasty one, it is known to go with a terrific bang, leaving a huge mess.I would replace the three.
Note the polarity of the filter capacitor - remember this Beomaster has positive ground.
The three largest capacitors has been changed. The inside cleaned.It works! The sound is still nice, in spite of my molestation.It was difficult. Specially soldering those points where legs of the caps and several cables go together was difficult.I'll leave the restoration from now to pro's. Too much for an amateur like me. If you saw my solder joints you may ban me from this forum.It was fun though, studying and preparing.Someone who could restore them for me?!I now have three machines, two white keyed and one black. And I have sets of components for restoring two.I have become a complete fan of the white keyed Beomaster..They white ones all have their own individual cosmetical problems. I would love to have one in mint condition, or nearly mint. What do you do when the scale front rail has broken off, like in my earlier photo? I don't want to scrap it as a spares machine, I would hate that, and it is in nice condition except from this. Was thinking of building a new front, but I am not really good at such things.
Again, I must say how impressed I am with the sound of this little receiver!I have had several vintage, mostly 70ies, receivers and setups with different speakers. I believe I was looking for a special sound, I think this is it, perhaps you can call it warmth. It has been playing some challenging music today, that my other setups couldn't do justice to. Indie-pop for example, heavily guitarbased indie-pop never sounded this good. Those dreamy shoegaze guitars can make your ears bleed on the wrong stereo but sound heavenly on the right. But it can also play house and techno, there is enough deep end. And it is lovely with jazz too, just played Diana Krall. And with 80'ies music, now I could really enjoy ABC's 80-hits. It goes well with any kind of music. Bought a used Sony Discman and going thru my cd collection, which I haven't heard for years. So much fun.The Beomaster 1000 survived my restoration attempt. It plays beautifully.This is my favourite amplifier ever.
Jacques, I have the virus, definitely..It's good to have this forum to have the support of fellow infectees.There are so many of these machines for sale on ebay and local ads, and they cost so little. But I already have three, why do I keep looking in these ads and wanting to buy another one..?You know, the design has grown tremendously on me too. First I thought it older looking than the 70'ies receivers I had, and I thought the 1001 and 1200 really cool looking. But now I really appreciate the 1000's aesthetics. It is more than a receiver, almost like a piece of litte furniture.And then, as you recommend I have to get myself a beogram 1000 too.Now I use the newly bought Discman and a Nuforce DAC.Oh, I have a question for you, if anyone can answer?The Beomaster 1000 has three inputs. One is Tape, which I normally use for line out from my source (computer/DAC).But now I have two sources, and to avoid having to switch cables, I want to use one of the other inputs on the receiver, there are Gram1 and Gram2. In the specs it says: Gramophone input 1: GV 42 VF Stereo record player or crystal pick-up: sensitivity 15mV/50mW.Gramophone input 2: G 42 V Stereo record player (less pre-amplifier). Sensitivity 200 uV/47KOhm at 50 mV.I tried briefly the gram inputs from the CD line out to the gramophone inputs, Gram1 sounds fine, Gram2 sounds like overload.Is it ok to use the Gram1 for a line out from my a DAC or CD? As I understand it is still for a weaker signal than Tape, but it sounds ok..Thanks for all your help!
Gram 1 is OK, and here just to feed your BeoVirus
The QI input is indeed made to accept ceramic cartridges, once found on lesser turntables. The same type found on Dansettes if you prefer. It isn't really suited to anything else.And not quite hi-fi!
Even the Tape input will be saturated by the 2V of CD players and DACs. You need an attenuator, unless your sources have a volume control.
The Beomaster will give its very best with an SP6 (Beogram connected to QII) and through its very own radio section.
Thanks Sören and Jacques!
After all, there are worse addictions.. This is not bad for health at all. Not even that detrimental to the wallet.The inputs, hmm.. No level control on the CD but the DAC has. It sounds really good from the Discman though, even though possibly too much fed into the poor thing. So you are saying that the Q1 and Q2 shouldn't be used at all (except for gramophones) for quality sound?An attenuator! Shouldn't be too difficult to cook one up myself. Anyone has a recipe?By the way, I was surprised at the radio section. Not that I listen much to radio, Swedish radio is quite horrible, except P1 the state channel that plays some jazz and classic. My other vintage receivers, like Tandberg, usually need an antenna. I didn't even expect the radio section work on this BM1000, but it works super and stations are loud and clear, better than any of my other receivers, although I didn't even connect an antenna.
Too high line level is perhaps a bigger problem than I thought.I have experienced these problems:
Most line level components (CD, Tape, Tuner etc) have rather too much gain (particularly CD) which results in an amplifiers full volume point being reached around halfway on the volume control. This gives the impression of lots of power but can make it all too easy to damage speakers. More importantly though volume controls are actually quite inaccurate and degrade the sound more when they are at lower levels.(from Rothwell Audio Products)Perhaps this is the solution:http://www.rothwellaudioproducts.co.uk/html/attenuators.htmlReview here:http://www.enjoythemusic.com/magazine/equipment/0803/rothwell.htm
Jeppe:Perhaps this is the solution:http://www.rothwellaudioproducts.co.uk/html/attenuators.html
--mika