When I was a young bloke, I had a Labcraft turntable and always lusted after one of these. I had to make do with an Akai. I enjoyed watching your restoration. Thank you.
I owned several B & O Beomaster receivers. What a statement they are, obviously sent to us from the future. Capacitors becomes an issue as they age, and service can be most expensive (if you can find a shop that will work on them).
When I was a B&O dealer in London, B&O would supply us with panels so that we could change the colour to the customers requirements. The rosewood was the most popular colour. B&O was fairly reliable as products went but did suffer from slightly inferior internal components like the trim pots. We used to keep large packets of indicator lamps because they did fail on a regular basis.
@@electronicsoldandnew Thats what we used to do a lot of the time. We used to replace them with enclosed trimmers with moulded canon tracks. We would buy them from a company called RS Components who were known for their exceptional quality. They used to supply the avionics and development companies.
Father has one of theses but with the addition of a built-in tape player, still looks and sounds great never been serviced or repaired as far as I know. Quality stuff back in the day
Thank you so much for this video, gave me the guts to tackle a Beocenter 1600 I brought last week. First time Vintage Hifi repair. Currently replacing all the red 100/40 ROE caps, 50% were leaking, one with top about to explode, it disintegrated on removal. Currently listening to it on FM after recapping, a nice smooth sound how I remember stereo radio sounded. Replaced tuning bulbs, now also working, cool dimming effect now fully functional. Now await replacement tape drive belt to repair tape drive, was working but now snapped. Looking forward to a fully-functional unit. Enjoy your nicely explained commentary to your videos. Thanks for your time and commitment
Very nice! Many years ago, I repaired one like this for a friend. That was qiute challenging, because the mains transformer had an open winding. This one is very special, it has to have very exact measurements in order to fit in. Not very easy.. The solution was to use an external one in a case.. Also, those "ROE" capacitors (for Roederstein & Türk in Germany) are very reliable as I have experienced
Great little project. I really hope your daughter is enjoying this nice piece of hifi history. My daughter just had her 23rd birthday yesterday, so about the same age...
Lovely piece of kit this. I remember in the early 1970s when top-end record shops and electrical outlets like Manchester and Midland had lots of B & O stuff. These days, it seems to be only specialised B & O shops. Fascinating now to see how the indicators worked before LEDs came into use.
I rescued one of these from the rain last week, shortly before it would have been carted off to the dump too. It had been sitting out for several weeks by the look of it but was remarkably dry on the inside, although pretty manky. The circuit diagram was still there and had also escaped the weather by a stroke of good fortune. Some not too brilliant repair work had been done in the past and it has a 1n capacitor missing but I think it can be made to work OK.
Great video. Nicely done filming it all. Great explanation. Hopefully you will do more repairs of Bang & Olufsen equipment. Looking forward to it. Thank you 👍
Just finished restoring my second one of this model. The large filter capacitors were fine on both BUT they are so big they make it impossible to access, or even see, several resistors in that part of the board. So worth cost of replacing even just for that. In both the ones I've restored there has been at least one failing transistor or out of spec resistor in the power amp section so worth checking those and they are very cheap to replace. Whilst the orange caps have been fairly good on both the 901 I've worked on I had a 3rd one to strip for parts (the slide potentiometers etc.) that one had more than half cracked open so you could see the rolled up internals. BTW this model was revised during its production history to a version using TIP120/125 output transistors which are mounted on the other (conductor) side of the main board and are just screwed to the heatsink, so they don't have the metal bar clamping them to the heatsink. There are also some changes in the PCB traces in that area to accommodate this and also the resistors around the bias transistor are different values (the one I had with this showed these changes on the schematic attached inside the lid). The one I've just done, identical to this one, was a "for parts" on eBay as it had no Left channel sound, this was caused by a screw on that side that holds the heatsink to frame being missing, so the heatsink could move putting strain on and cracking the solder joint of the BD697 NPN output transistor on that channel, the waveform right back through the power section showed the top half of the test waveform as missing which gave it away where to look. Definitely clean the boards before crack hunting as I couldn't actually see the solder crack at all until I cleaned 50 years of dust and grime off 🤢 Its worth REALLY cleaning the front panel switches again if you have a problem as they are source of many issues, also worth pulling the black plastic part (that holds the aluminium square) off the front of the white plastic switch plunger when working the switch with the contact cleaner so you can also push down a little on the front of the plunger (i.e. towards top of the case) as you do it as this helps cleaner by rubbing a little more at contacts at back of the switch (had a missing left Phono channel on this latest one and testing the switch for continuity I found the Left side was not making contact between the pins when Phono button depressed whilst the Right was, I could feel the gritty corrosion coming off as I worked it applying that little bit of pressure to push the the contacts at rear of the switch into each other). One tip worth knowing as regards the fine tuning: the thin white rubber strip that the fine tuning wheel runs along isn't actually glued in. So if yours is cracked up on the surface you can prise it up with some tweezers from one end and work you way along the track turning it over (no need to remove the tuning slider, just carefully work your way under it), then you'll have a pristine "like new" surface of rubber for the fine tuning wheel that will grip better and be more consistent, its like a new part for FREE 😎 Also its easy to find teak veneer to re-face the side panels, I bought two small "sample" sheets on eBay that have done both of my receivers. Just 3 light coats of Danish Oil, and two on the lid of the receiver (once cleaned with alcohol and fine wire wool) to bring the whole thing back to a nice "original" style finish... you have to wait a good few hours between coats but it is worth it.
Today you can easily replace the three large capacitors with std. Rubicon PK that has the same size as the orange ones and therefore can be set directly upright!
I really enjoyed watching that..I just brought myself the 901and the green light dosnt work...now I'm thinking I should be able to mimic your moves....fingers crossed i do a good job ....thanks mate from mandurah western Australia
15:45 Hehe, they were brittle back in the 70s when they were new. The chopstick replacement will work better and last forever - it's bamboo. Nice to see you into one of these. I serviced the Beograms in 1975-1979, the venerable 4000, 3000, etc. Only worked on one Beocenter back then. Everything was so packed in there so much, to make the exterior shape so slim. The service manuals were excellent and full of illustrations. And they sounded great in their systems.
Yes, bamboo to the rescue! I bet B&O designers never imagined such a hack :) They are a little cramped (not this one) because, as you say, the size of the units was really kept down to a minimum. I just love them, though. They look as modern today as they did back then. Quite a feat.
@@electronicsoldandnew They do look as modern today. Their phono cartridges were incredibly good sounding and their turntables were always interesting and ultra-modern.
Beautiful amp and nice work with it! As you changed the mains plug to Schuko type F instead of C, i would have changed the power cord also to a grounded one, for upgraded safety, as the chassis is metal. Greets from Finland, Madeira is such a beautiful place!
I sometimes do and sometimes don’t. The older equipment, like tube radios, are really dangerous, so I tend to do so in those. Greeting from Madeira, and stay safe.
Nice work. As an experienced B&O tech, I have some comments: The orange "ROE" capacitors seems to be ok, but if you ever come across the red ones, replace them all. You need to change the bulps to the correct values in order to get a brighter light and the luminance will seem more distributed / even. And now the most important part: The trimmers are black coated from corrosion and especially the trimmer for bias current must go. As you also experienced, there was a slip in one of them, where the voltage across the resistor rose dramatically - I bet the the output stage drew full power in that moment. If not changed, you will soon risk a thermal runaway with consequential damage to the output transistors.
Mogens Ranneries : thanks you very much for your input. I’ve had experience with the red caps in some Quads, and they were in fact really bad. I was pleasantly surprised with the condition of these orange ones. I am still looking for the correct bulbs and will replace these when I find them. I am also replacing the pots. These are in fact qui dangerous for the amp. Once again, thanks.
Mogens, I have bought the same 901 in the UK and the string on the volume pulley mechanism has come off, do you know how to fix this? Many thanks Simon Martin
Great repair as usual. I've been using a liquid CA glue accelerator to instantly set CA glues for years. Much cleaner than powdered bicarb of soda and won't tend to boil the glue or leave a white residue. Available online or in hobby stores. Comes in a pump bottle but you can just unscrew the pump, draw a bit of liquid into the tube, hold the tube end over the glue joint and press the plunger to put a few drops onto the glue. Very clean and lasts forever. As for having to search for a talk radio station among a sea of music stations -- I should be so lucky. Nothing but inane blather-radio where I live, even on FM. At least the static matches the tinnitus in my ears..;>)
I’ve been meaning to get the accelerator for ages, but always seem to forget. I have to get it online as I’ve never seen it in madeira. The talk radio syndrome is less serious here because we’re a small market for them and playing music is cheaper than paying a host. Being small has its advantages :)
Electronics Old and New by M Caldeira is the sound quality of Beomaster 901 on par with Tandberg or Luxman? There’s not much information on sound quality of these sleek receivers.
I was nearly choked to hear that this thing was going to be dumped! Now that would have been a crime against humanity because these B&O receivers are gorgeous pieces of art in addition to great HiFi gear of yesteryear. So glad you saved this one. I'm sure your daugther will be proud to have it . Great video, thanks for sharing.
Electronics Old and New by M Caldeira In B&O we have a designer who made a “detailed” drawing . When we (electronic and mechanical engenier) recieved this drawing we started the detailes. It took about 1 1/2 year before it was ready for production.
I am honoured to have your comments on my channel. As I mentioned in the video, the mechanical aspects really surprised me due to their simplicity and effectiveness. You guys were truly far far ahead of all the competition. Thanks again for your excellent solution.
I have just done the restoration of this little receiver. Of course, the coupling and filter caps were all dead. And I was "lucky" to have to remove and disassemble and then reassemble the crackling main volume potentiometer... A Rubic cube is just a breeze compared to it. Nevertheless, the restoration was successful. I have to point out one special feature - as I have had the potentiometer opened: the amplifier has an inherent loudness feature to a certain position of the volume slider - providing you feed the Tape input with a signal at around 200mV. Once you feed it with a hot 2V of a CD player or DAC, you are effectively captured within the active loudness part of the pot - as you have to use the lower part of it because of the multiple input power. Thus the loudness is active even on a loud volume - and the sound becomes really too beefy. So, you either have to decrease the input power on Tape input somehow or compensate the active loudness with bass and treble by setting the respective sliders click or two below zero.
That’s interesting. A little like the german tube radios used with taps off the pot to add tone-shaping for lower levels. That “hidden” feature on this one would play havoc with any frequency sweep testing if you did not consider that. Thanks.
Very nice - you have a lucky daughter! I remember drooling over them in hifi & electronics mags when i was a kid, but have never managed to see one in the flesh! About those Roederstein EK caps: never encountered them myself, though I have been told by people I know who have that they're (a) almost always still good, or (b) rubbish 😜. The former from those familiar with them as coupling caps in 100% typical solid-state gear, while the latter is the (very strongly voiced!) opinion of a friend who is something of a Quad expert - I believe they were used in the tube-based Quad 22? Maybe they simply don't like heat… And is there anything chopsticks can't do? 😉
The Roe caps are indeed used in Quad gear. If I’m not mistaken, I have one of the preamps here with them in. At least if they explode, the colour scheme will be interesting :)
What a great video. So clear. I have inherited one of these amps. It works ok except for bulbs. I’ve got confidence to try to fix, but where can I get the replacement 12v bulbs?
I started my audio obsession with a Beomaster 901 that my parents let me have as they got something else (that was much inferior LOL). It was an awesome receiver for its time. I miss it.
Fantastic job with this gem. I suggest you to try to find any superb receiver / amplifier from Tandberg...specially the Huldra line. Huldra 10, 11 and 12 are incredible elaborated on the RX side. I've got a Huldra 12 (circa 1978) and shines on FM, MW, LW and covers 3 to 30 MHz. Greetings from Leeds....Jorge M0LDW/LW5DX
Hi, Really loving this channel. I know this video is about a year old, but i have some usefull things to add. The small red tantalum caps drift a lot. I have fixed some 901's in the past, and found them to be in very bad condition. this causes all kind of small problems. Channels not beeing equal, stereo indication not working properly etc. Also it's a good idea to check if the discriminator is correctly set at 0 volts. (S curve). Nice to adjust the tuning lights so they light up the same, but first you have to be sure the discriminator is working perfect. Good idea to replace the main electrolitics, and in my experience the orange caps most of the time are ok. Good luck with this great amp. For even better sound, bypass the output caps with a small value wima pet, value not critical. 47nf/100nf is fine. The sound will become more accurate because of d.a. from the standard ecap being corrected by it's small filmcap brother. Good luck! Best regards from the Netherlands, Nico den Haak.
Hello Mr Caldeira, I'm also learning stuff from your channel, so that's great too. I also own a Grundig 3400, which i purchased some 25 years ago. A customer of mine brought it in for repair. The radio was used by his kids to "play" with in their bedroom. I was shocked, and gave them enough money so they could buy their kids a portable radio/cd. I restored it, and it's in my collection ever since.
Bonjour pouvez-vous me donner les références des références des 3 nouveaux condensateurs que vous avez changé Merci pour cette belle vidéo Cordialement
I hope the daughter knows how fortunate She is to have a system like this. At her age I would have gladly sold my parents into bonded servitude for a B&O system.
I decided to give it to her to avoid the temptation of selling us into bonded servitude. Oh, wait! We’ve just raised a child to the age of university ... we’ve been in bonded servitude for over 20 years!
Really informative video ive worked on Beomaster 4000 etc and the procedure are very similar as a pointer somehow you have managed to fit the side panels incorrectly they would never stick out at the front like that it could be you have them on the wrong ends. As usual a great video thanks for posting it.
The panels are not properly inserted because I have not quite finished them yet. I mentioned that in the video. They were just lightly fitted to complete the look :)
VERY interesting repair/restore video. I subscribed to you channel because of it's excellent explanations and good video technique. Any idea what year this beauty was manufactured?
Those orange caps do seem to last for ever however the smaller brown ones cases due crack at the top and the electrolyte drys up .Be careful those trimmers the metal plating oxidize causing erratic resistance must clean first .I love the B&O stuff of this era not the newer stuff
You should really check this out at full load against a 4 ohm resistance. You will then find the following: The output device thermal compound has dried, clean and replace, re-torque. Output capacitors will be subject to higher voltage than specified, go to next voltage level when replacing. etc
Built to last. I would have replaced the crusty trimmers. Do i see it right, the scale und switches are without illumination? B&O built a very modern style in the 70s. Congrats for this lucky catch.
It is pressed onto the sides and has four plastic “pins” that go into the chassis. You need gently pry them loose (see the video) but be careful because they are brittle (I broke one of mine off).
In your video, I noticed cork debris on the tuning dial knob groove. Did you clean the grooves of the cork debris? Maybe that will help the tuning knob slide better?
I would be wary of those plastic ROE (Roederstein) branded caps as they have a habit of failing short. They were pretty high-end caps back in the day, with lots of European manufacturers favouring them. Unfortunately, they became quite notorious in the B&O TV's as they would be full of the dark red ones, and blanket replacement was often the only cure. Perhaps the orange ones hold up better? Even still, they're pretty long-in-the-tooth by now. Frolyt in East Germany also made a similar type in white plastic cans - they are terrible also. Other ROE or Frolyt caps are generally fine - just watch out for the plastic versions.
These are plastic, but as I said, I’ve never seen caps of this age holding out so well. I may replace them all in the future, but left them is for now. Perhaps it’ll force my daughter to visit for the repair :)
What caps did you use for the big filter caps? I have one on the bench with DC on the speaker outputs. Are they dual caps? Edit: I just found a layout online, and they’re big radial caps with a solder lug on the back to hold them on the board. Standard high quality radials with a dab of silicon to hold them down should be fine.
The radio tuning set-up looks like it would be nerve-wracking to me. I prefer the conventional tuning knob to that slider. Each to their preference. Cool unit that looks like it would be a hassle to work on the boards with everything crammed together.
11:55; Ha! So it's the red Rodersteins that are evil but the orange ones are great? Imagine that! Are they actually 100V 40μF or have I misread them? If they are, you could in theory replace them all with film caps. It might cost a little more but you'd only need to do it once. I've been able to get loads of 40μF film caps on ebay for cheap by buying bulk - the verdict is not yet out on whether they were fakes or not, we'll see...
6:55 : If I wanted to taunt you I'd urge you to try repairing a 3001 after this but that would be rather sadistic so I won't : ) Suffice it to say, I gave up on that unit (not one of my finest moments but I was moving at the time and the receiver was in a dismantled state so...).
@@electronicsoldandnew I kept the transformer and PSU I think. The transformer was impressive, fully potted (!) and felt a shame to throw away. It was the case though that was the real nightmare: it was one of these affairs where each side is held together by screws with the other sides but in such a way that you had to completely disassemble everything simply to get inside (or so it seemed to me back then). Quite the opposite of what you have here.
Good looking unit, very techno style. Glad it was an easy fix to watch in its entirety . Thanks By the way, we have orders to shut all the bars and pubs in the Houston, Texas area also....dang it...I thought ALCOHOL kills this Cov19 bug ! J K
I wonder if I would get arrested if I filled my hot tub with alcohol and invited 6 attractive ladies over to party....would we still need to "DISTANCE " ourselves to avoid contamination ? Of course , that would be a waste ! J K ;-)
DIN sockets were often poorly executed and introduced huge amounts of noise because of the gain needed compared to RCA phono circuits. Sometimes on cassette decks, the DIN input would add over 10db of noise essentially negating any benefit of Dolby B noise reduction!
Me looking at the EU schuko plug while hearing you speak with that British accent: something's wrong here. Me moments later when realising Portuguese is being broadcasted: ah!
@@electronicsoldandnew from Porto. I'm in the middle of your primaluna video right now. I have that exact same amp, still strong after 14 years. Eheh. Lots of catching up to do, now that we are locked in. Stay home and safe!
Electronics Old and New by M Caldeira used to work for Etkinds in Kempton City ( Kempton Park ) in the early 70’s and sold B&W product, loved the product. What amazes me is how the style has not aged.
Lovely unit, wanted one of these way back. I do have the slightly down market 1700 series, still very good , works well and good sound quality. flic.kr/p/8G1jD4
When I was a young bloke, I had a Labcraft turntable and always lusted after one of these. I had to make do with an Akai. I enjoyed watching your restoration. Thank you.
My pleasure
Il vallait combien cette ampli tuner à l'époque, merci 👍
I owned several B & O Beomaster receivers. What a statement they are, obviously sent to us from the future. Capacitors becomes an issue as they age, and service can be most expensive (if you can find a shop that will work on them).
True
Beautiful job! I once repaired a Tandberg tuner amp that had vericap tuning and the FM quality was out of this world!
I agree. These guys sound amazing.
The baking soda trick comes in handy more often than I'd think.
Cumprimentos da Alemanha!
👍
When I was a B&O dealer in London, B&O would supply us with panels so that we could change the colour to the customers requirements. The rosewood was the most popular colour. B&O was fairly reliable as products went but did suffer from slightly inferior internal components like the trim pots. We used to keep large packets of indicator lamps because they did fail on a regular basis.
I agree that the trim pots could be better. Easy enough to change though.
@@electronicsoldandnew Thats what we used to do a lot of the time. We used to replace them with enclosed trimmers with moulded canon tracks. We would buy them from a company called RS Components who were known for their exceptional quality. They used to supply the avionics and development companies.
Jeremy Travis : RS is still around and going strong.
@@electronicsoldandnew 😊
Father has one of theses but with the addition of a built-in tape player, still looks and sounds great never been serviced or repaired as far as I know. Quality stuff back in the day
Yes it was, and quite expensive too.
Thank you so much for this video, gave me the guts to tackle a Beocenter 1600 I brought last week. First time Vintage Hifi repair. Currently replacing all the red 100/40 ROE caps, 50% were leaking, one with top about to explode, it disintegrated on removal. Currently listening to it on FM after recapping, a nice smooth sound how I remember stereo radio sounded. Replaced tuning bulbs, now also working, cool dimming effect now fully functional. Now await replacement tape drive belt to repair tape drive, was working but now snapped. Looking forward to a fully-functional unit. Enjoy your nicely explained commentary to your videos. Thanks for your time and commitment
My pleasure. Enjoy your system.
I have owned a couple of Beomaster 901s, very lovely warm sound! They control the bass very well and everything else is great too.
It sounds good.
L'acoustique de cette appareil est incroyable
Combien coûter cette appareil à l'époque ?
Svp
Very nice! Many years ago, I repaired one like this for a friend. That was qiute challenging, because the mains transformer had an open winding. This one is very special, it has to have very exact measurements in order to fit in. Not very easy.. The solution was to use an external one in a case.. Also, those "ROE" capacitors (for Roederstein & Türk in Germany) are very reliable as I have experienced
I can imagine the difficulty in fitting another transformer in there. Not easy at all.
I really enjoy the B & O design concepts. I frequent the beoworld forums. I really love the older systems they maid. Good entertaining video.
They were a dream of mine back when I was at varsity. Loved the designs.
Great little project. I really hope your daughter is enjoying this nice piece of hifi history. My daughter just had her 23rd birthday yesterday, so about the same age...
She certainly uses it when she’s home from university. She decided to leave it at home.
Really nice receiver/amplifier set and nice repair, thanks!
Thank you
Brilliant video thanks for the great info and detail, a lovely piece of kit, I will now go off and see what I can do with my Beocenter 4000 :)
👍
Lovely piece of kit this. I remember in the early 1970s when top-end record shops and electrical outlets like Manchester and Midland had lots of B & O stuff. These days, it seems to be only specialised B & O shops. Fascinating now to see how the indicators worked before LEDs came into use.
👍
I rescued one of these from the rain last week, shortly before it would have been carted off to the dump too. It had been sitting out for several weeks by the look of it but was remarkably dry on the inside, although pretty manky. The circuit diagram was still there and had also escaped the weather by a stroke of good fortune. Some not too brilliant repair work had been done in the past and it has a 1n capacitor missing but I think it can be made to work OK.
Good luck. It’s well worth saving.
Thank you. Your video should help quite considerably.@@electronicsoldandnew
Great looking, well built unit. 20 WPC is more than enough for speakers with decent efficiency.
True
I always learn a lot watching your videos. Thank you.
Very nice revision of this quite nice radio.congratulations as ever,and thank you for the easy opening of the radio.
My pleasure
Excellent video, my compliments!
thanks
Great video. Nicely done filming it all. Great explanation. Hopefully you will do more repairs of Bang & Olufsen equipment. Looking forward to it. Thank you 👍
Thanks. I actually have another little surprise up my sleeve for the near future :)
Just finished restoring my second one of this model. The large filter capacitors were fine on both BUT they are so big they make it impossible to access, or even see, several resistors in that part of the board. So worth cost of replacing even just for that. In both the ones I've restored there has been at least one failing transistor or out of spec resistor in the power amp section so worth checking those and they are very cheap to replace. Whilst the orange caps have been fairly good on both the 901 I've worked on I had a 3rd one to strip for parts (the slide potentiometers etc.) that one had more than half cracked open so you could see the rolled up internals. BTW this model was revised during its production history to a version using TIP120/125 output transistors which are mounted on the other (conductor) side of the main board and are just screwed to the heatsink, so they don't have the metal bar clamping them to the heatsink. There are also some changes in the PCB traces in that area to accommodate this and also the resistors around the bias transistor are different values (the one I had with this showed these changes on the schematic attached inside the lid). The one I've just done, identical to this one, was a "for parts" on eBay as it had no Left channel sound, this was caused by a screw on that side that holds the heatsink to frame being missing, so the heatsink could move putting strain on and cracking the solder joint of the BD697 NPN output transistor on that channel, the waveform right back through the power section showed the top half of the test waveform as missing which gave it away where to look. Definitely clean the boards before crack hunting as I couldn't actually see the solder crack at all until I cleaned 50 years of dust and grime off 🤢 Its worth REALLY cleaning the front panel switches again if you have a problem as they are source of many issues, also worth pulling the black plastic part (that holds the aluminium square) off the front of the white plastic switch plunger when working the switch with the contact cleaner so you can also push down a little on the front of the plunger (i.e. towards top of the case) as you do it as this helps cleaner by rubbing a little more at contacts at back of the switch (had a missing left Phono channel on this latest one and testing the switch for continuity I found the Left side was not making contact between the pins when Phono button depressed whilst the Right was, I could feel the gritty corrosion coming off as I worked it applying that little bit of pressure to push the the contacts at rear of the switch into each other). One tip worth knowing as regards the fine tuning: the thin white rubber strip that the fine tuning wheel runs along isn't actually glued in. So if yours is cracked up on the surface you can prise it up with some tweezers from one end and work you way along the track turning it over (no need to remove the tuning slider, just carefully work your way under it), then you'll have a pristine "like new" surface of rubber for the fine tuning wheel that will grip better and be more consistent, its like a new part for FREE 😎 Also its easy to find teak veneer to re-face the side panels, I bought two small "sample" sheets on eBay that have done both of my receivers. Just 3 light coats of Danish Oil, and two on the lid of the receiver (once cleaned with alcohol and fine wire wool) to bring the whole thing back to a nice "original" style finish... you have to wait a good few hours between coats but it is worth it.
Thanks for sharing your experience 👍
Today you can easily replace the three large capacitors with std. Rubicon PK that has the same size as the orange ones and therefore can be set directly upright!
👍
Nicely done. I have a pair of Beovox s40's that would go very nicely with this receiver.
They sure would
I really enjoyed watching that..I just brought myself the 901and the green light dosnt work...now I'm thinking I should be able to mimic your moves....fingers crossed i do a good job ....thanks mate from mandurah western Australia
Good luck
15:45 Hehe, they were brittle back in the 70s when they were new. The chopstick replacement will work better and last forever - it's bamboo. Nice to see you into one of these. I serviced the Beograms in 1975-1979, the venerable 4000, 3000, etc. Only worked on one Beocenter back then. Everything was so packed in there so much, to make the exterior shape so slim. The service manuals were excellent and full of illustrations. And they sounded great in their systems.
Yes, bamboo to the rescue! I bet B&O designers never imagined such a hack :)
They are a little cramped (not this one) because, as you say, the size of the units was really kept down to a minimum. I just love them, though. They look as modern today as they did back then. Quite a feat.
@@electronicsoldandnew They do look as modern today. Their phono cartridges were incredibly good sounding and their turntables were always interesting and ultra-modern.
Beautiful amp and nice work with it! As you changed the mains plug to Schuko type F instead of C, i would have changed the power cord also to a grounded one, for upgraded safety, as the chassis is metal. Greets from Finland, Madeira is such a beautiful place!
I sometimes do and sometimes
don’t. The older equipment, like tube radios, are really dangerous, so I tend to do so in those.
Greeting from Madeira, and stay safe.
That looks so good.. Candy for the eyes.. I wish i can put that on my set up.
It is a great little set.
Thank you for your good job Sir ! Greetings from #Algeria ❤🇩🇿
Nice work. As an experienced B&O tech, I have some comments: The orange "ROE" capacitors seems to be ok, but if you ever come across the red ones, replace them all. You need to change the bulps to the correct values in order to get a brighter light and the luminance will seem more distributed / even. And now the most important part: The trimmers are black coated from corrosion and especially the trimmer for bias current must go. As you also experienced, there was a slip in one of them, where the voltage across the resistor rose dramatically - I bet the the output stage drew full power in that moment. If not changed, you will soon risk a thermal runaway with consequential damage to the output transistors.
Mogens Ranneries : thanks you very much for your input.
I’ve had experience with the red caps in some Quads, and they were in fact really bad. I was pleasantly surprised with the condition of these orange ones.
I am still looking for the correct bulbs and will replace these when I find them.
I am also replacing the pots. These are in fact qui dangerous for the amp.
Once again, thanks.
Mogens, I have bought the same 901 in the UK and the string on the volume pulley mechanism has come off, do you know how to fix this? Many thanks Simon Martin
@@realaleguideI have forwarded the service manual to your facebook messenger account
Nice Job, and a good looking receiver
Thanks
Outstanding work as always. Well done.
Thanks
Great repair as usual. I've been using a liquid CA glue accelerator to instantly set CA glues for years. Much cleaner than powdered bicarb of soda and won't tend to boil the glue or leave a white residue. Available online or in hobby stores. Comes in a pump bottle but you can just unscrew the pump, draw a bit of liquid into the tube, hold the tube end over the glue joint and press the plunger to put a few drops onto the glue. Very clean and lasts forever. As for having to search for a talk radio station among a sea of music stations -- I should be so lucky. Nothing but inane blather-radio where I live, even on FM. At least the static matches the tinnitus in my ears..;>)
I’ve been meaning to get the accelerator for ages, but always seem to forget. I have to get it online as I’ve never seen it in madeira.
The talk radio syndrome is less serious here because we’re a small market for them and playing music is cheaper than paying a host. Being small has its advantages :)
The accelerator works very well, but I think that when sturdiness is needed the baking soda works better.
Agreed
ESR meter is very useful tool 🙂 Interesting that the capacitors are in such a perfect state after all these years. Excellent video!
Thanks
Electronics Old and New by M Caldeira is the sound quality of Beomaster 901 on par with Tandberg or Luxman? There’s not much information on sound quality of these sleek receivers.
I was nearly choked to hear that this thing was going to be dumped! Now that would have been a crime against humanity because these B&O receivers are gorgeous pieces of art in addition to great HiFi gear of yesteryear. So glad you saved this one. I'm sure your daugther will be proud to have it .
Great video, thanks for sharing.
I feel the same. Love these things.
What a lovely piece of equipment. I bet it was hard to give away...
She deserves it (but she better treat it right)
I have made the mechanical construction in 1971
I don’t understand. Do you mean you were involved in the design of this machine?
Electronics Old and New by M Caldeira
In B&O we have a designer who made a “detailed” drawing . When we (electronic and mechanical engenier) recieved this drawing we started the detailes. It took about 1 1/2 year before it was ready for production.
I am honoured to have your comments on my channel. As I mentioned in the video, the mechanical aspects really surprised me due to their simplicity and effectiveness. You guys were truly far far ahead of all the competition. Thanks again for your excellent solution.
This was a proper service.
👍
I have just done the restoration of this little receiver. Of course, the coupling and filter caps were all dead. And I was "lucky" to have to remove and disassemble and then reassemble the crackling main volume potentiometer... A Rubic cube is just a breeze compared to it.
Nevertheless, the restoration was successful. I have to point out one special feature - as I have had the potentiometer opened: the amplifier has an inherent loudness feature to a certain position of the volume slider - providing you feed the Tape input with a signal at around 200mV. Once you feed it with a hot 2V of a CD player or DAC, you are effectively captured within the active loudness part of the pot - as you have to use the lower part of it because of the multiple input power. Thus the loudness is active even on a loud volume - and the sound becomes really too beefy. So, you either have to decrease the input power on Tape input somehow or compensate the active loudness with bass and treble by setting the respective sliders click or two below zero.
That’s interesting. A little like the german tube radios used with taps off the pot to add tone-shaping for lower levels. That “hidden” feature on this one would play havoc with any frequency sweep testing if you did not consider that. Thanks.
The Beomaster 901 - the Beowulf of B&O... nice.
Very nice - you have a lucky daughter! I remember drooling over them in hifi & electronics mags when i was a kid, but have never managed to see one in the flesh!
About those Roederstein EK caps: never encountered them myself, though I have been told by people I know who have that they're (a) almost always still good, or (b) rubbish 😜. The former from those familiar with them as coupling caps in 100% typical solid-state gear, while the latter is the (very strongly voiced!) opinion of a friend who is something of a Quad expert - I believe they were used in the tube-based Quad 22? Maybe they simply don't like heat…
And is there anything chopsticks can't do? 😉
The Roe caps are indeed used in Quad gear. If I’m not mistaken, I have one of the preamps here with them in.
At least if they explode, the colour scheme will be interesting :)
These 70ies beomaster amps. ARE VERY NICE.
I agree :)
What you should think about is the tantalium caps, the are over age and I had problem with this before.
👍
New to your channel. Love the video and the unit you chose to work on.
Welcome.
Those little plastic pegs would be a good candidate for 3D printing replacements.
Yes they would.... or you can simply carve a chopstick :)
Seriously though, they’re all brittle and printed replacements would be an excellent option.
supercool receiver and well engineered,great job !
Thanks
What a great video. So clear. I have inherited one of these amps. It works ok except for bulbs. I’ve got confidence to try to fix, but where can I get the replacement 12v bulbs?
Remove one of them and try auto parts sellers. Sometimes they stock similar bulbs as dash-board lamps.
I started my audio obsession with a Beomaster 901 that my parents let me have as they got something else (that was much inferior LOL). It was an awesome receiver for its time. I miss it.
Time to get another one :)
They’re a lot cheaper now.
Fantastic job with this gem. I suggest you to try to find any superb receiver / amplifier from Tandberg...specially the Huldra line. Huldra 10, 11 and 12 are incredible elaborated on the RX side. I've got a Huldra 12 (circa 1978) and shines on FM, MW, LW and covers 3 to 30 MHz. Greetings from Leeds....Jorge M0LDW/LW5DX
I didn’t know that line, but have just looked them up. They do look great 👍
Hi,
Really loving this channel. I know this video is about a year old, but i have some usefull things to add.
The small red tantalum caps drift a lot. I have fixed some 901's in the past, and found them to be in very bad condition. this causes all kind of small problems. Channels not beeing equal, stereo indication not working properly etc. Also it's a good idea to check if the discriminator is correctly set at 0 volts. (S curve). Nice to adjust the tuning lights so they light up the same, but first you have to be sure the discriminator is working perfect.
Good idea to replace the main electrolitics, and in my experience the orange caps most of the time are ok. Good luck with this great amp. For even better sound, bypass the output caps with a small value wima pet, value not critical. 47nf/100nf is fine. The sound will become more accurate because of d.a. from the standard ecap being corrected by it's small filmcap brother. Good luck!
Best regards from the Netherlands,
Nico den Haak.
Thank you Nico for your advice. Always good to have these ideas from other peoples experience.
Thank you Nico for your advice. Always good to have these ideas from other peoples experience.
Hello Mr Caldeira,
I'm also learning stuff from your channel, so that's great too.
I also own a Grundig 3400, which i purchased some 25 years ago. A customer of mine brought it in for repair. The radio was used by his kids to "play" with in their bedroom. I was shocked, and gave them enough money so they could buy their kids a portable radio/cd.
I restored it, and it's in my collection ever since.
It is really shocking how some people treat these radios. enjoy yours
Might be worthwhile to use wire wool on the end panels after completing the finish. This would take away excess sheen. Always look impressive.
I’ve just done that. Makes a big difference.
Bonjour pouvez-vous me donner les références des références des 3 nouveaux condensateurs que vous avez changé
Merci pour cette belle vidéo
Cordialement
i dreamed of these too
I have a BO 4000 , why only the aux botón doesn’t work...any suggestions? Thank you 👍
No idea, I’m afraid. Haven’t opened up one of those yet.
one of my favs
I really love these things.
A brief summary of cat noises:
19:20
19:25
19:38
19:47
21:13
He’s a nosey bugger. Always around, trying to learn, I guess :)
Another interesting, many thanks
Interesting video......
My pleasure
Great video. I have cleaned and lubed the slider pots with Servisol. What did you lube the slider plastic parts with?
i use various products. i think in this one i used silicon grease, if i remember correctly
I hope the daughter knows how fortunate She is to have a system like this. At her age I would have gladly sold my parents into bonded servitude for a B&O system.
I decided to give it to her to avoid the temptation of selling us into bonded servitude. Oh, wait! We’ve just raised a child to the age of university ... we’ve been in bonded servitude for over 20 years!
Really informative video ive worked on Beomaster 4000 etc and the procedure are very similar as a pointer somehow you have managed to fit the side panels incorrectly they would never stick out at the front like that it could be you have them on the wrong ends. As usual a great video thanks for posting it.
The panels are not properly inserted because I have not quite finished them yet. I mentioned that in the video. They were just lightly fitted to complete the look :)
Fascinating stuff. Always admired B&O design... sound was only average though.
I always drooled over these units.
VERY interesting repair/restore video. I subscribed to you channel because of it's excellent explanations and good video technique. Any idea what year this beauty was manufactured?
They were made between 72/77. Here is more info;
www.beoworld.org/prod_details.asp?pid=380
I have rescued one in good condition, what are the parts you replaced and might you recommend a place to get them, thanks
It’s been a while. The video gives you info on the parts. Normal suppliers have them all (Mouser, Digikey ...)
Those orange caps do seem to last for ever however the smaller brown ones cases due crack at the top and the electrolyte drys up .Be careful those trimmers the metal plating oxidize causing erratic resistance must clean first .I love the B&O stuff of this era
not the newer stuff
paul davies : I’ve had the same experience with the brown ones. They’re terrible. I’m going to change the pot just to be safe.
I joyed this video
You should really check this out at full load against a 4 ohm resistance. You will then find the following: The output device thermal compound has dried, clean and replace, re-torque. Output capacitors will be subject to higher voltage than specified, go to next voltage level when replacing. etc
Good advice indeed, thanks.
Built to last.
I would have replaced the crusty trimmers.
Do i see it right, the scale und switches are without illumination?
B&O built a very modern style in the 70s. Congrats for this lucky catch.
The trimmers May well still be changed. They aren’t ally messed up. There is no illumination except for the stereo light and the tuning indicator.
Wow, there's a Portuguese FM station around 14:30 ! I know it's not Brazilian Portuguese... :-)
Yes, it’s a Portuguese station. I’m based on the island of Madeira.
Could you please show or describe in a bit more detail how to unclip the sides? I have a similar unit that needs the veneer repaired. Thanks
It is pressed onto the sides and has four plastic “pins” that go into the chassis. You need gently pry them loose (see the video) but be careful because they are brittle (I broke one of mine off).
@@electronicsoldandnew Thanks, I'll check again and see if I can get them loose.
In your video, I noticed cork debris on the tuning dial knob groove. Did you clean the grooves of the cork debris? Maybe that will help the tuning knob slide better?
Yes I did. The cork itself is a little dried out. Should improve with use.
@@electronicsoldandnew Your daughter might ask you to replace the cork strip after she see the video. Lucky it is available.
Would have been nice to hear audio through the AUX and Phono inputs too!
Stan Elder : you’re right. My apologies.
I would be wary of those plastic ROE (Roederstein) branded caps as they have a habit of failing short. They were pretty high-end caps back in the day, with lots of European manufacturers favouring them. Unfortunately, they became quite notorious in the B&O TV's as they would be full of the dark red ones, and blanket replacement was often the only cure.
Perhaps the orange ones hold up better? Even still, they're pretty long-in-the-tooth by now. Frolyt in East Germany also made a similar type in white plastic cans - they are terrible also. Other ROE or Frolyt caps are generally fine - just watch out for the plastic versions.
These are plastic, but as I said, I’ve never seen caps of this age holding out so well. I may replace them all in the future, but left them is for now. Perhaps it’ll force my daughter to visit for the repair :)
What caps did you use for the big filter caps? I have one on the bench with DC on the speaker outputs. Are they dual caps?
Edit: I just found a layout online, and they’re big radial caps with a solder lug on the back to hold them on the board. Standard high quality radials with a dab of silicon to hold them down should be fine.
I don’t recall exactly, but must have been Nichicon.
@@electronicsoldandnew All good. I ordered some
Nichicon Radial’s.
The radio tuning set-up looks like it would be nerve-wracking to me. I prefer the conventional tuning knob to that slider. Each to their preference. Cool unit that looks like it would be a hassle to work on the boards with everything crammed together.
I would be, but you’ve actually got full access to both sides of the board without removing it, so I think it’s not too bad.
Chopsticks are very useful.
They sure are 😊
11:55; Ha! So it's the red Rodersteins that are evil but the orange ones are great? Imagine that!
Are they actually 100V 40μF or have I misread them? If they are, you could in theory replace them all with film caps. It might cost a little more but you'd only need to do it once. I've been able to get loads of 40μF film caps on ebay for cheap by buying bulk - the verdict is not yet out on whether they were fakes or not, we'll see...
40uF film caps (if real 😊) are very very expensive. If you’ve found some, you’ve found treasure.
@@electronicsoldandnew That guy was selling them by the box, in bulk. Might still be doing that. Hang on I'll check..
I found an Epicure M100 today...but they didn't have a matching pair...oh well...
:)
Hmm wat you mean with that soda at 21 min because i din,t know that
It’s magic. Here is an example:
ua-cam.com/video/2tHhW1XOm2U/v-deo.html
27:17 Arnold
6:55 : If I wanted to taunt you I'd urge you to try repairing a 3001 after this but that would be rather sadistic so I won't : ) Suffice it to say, I gave up on that unit (not one of my finest moments but I was moving at the time and the receiver was in a dismantled state so...).
I understand completely. Sometimes you have to make tough decisions 😊
@@electronicsoldandnew I kept the transformer and PSU I think. The transformer was impressive, fully potted (!) and felt a shame to throw away. It was the case though that was the real nightmare: it was one of these affairs where each side is held together by screws with the other sides but in such a way that you had to completely disassemble everything simply to get inside (or so it seemed to me back then). Quite the opposite of what you have here.
The parts like the transformer are well worth keeping.
The design was based on the engineer's slide rule
interesting. that makes sense
Good looking unit, very techno style. Glad it was an easy fix to watch in its entirety . Thanks By the way, we have orders to shut all the bars and pubs in the Houston, Texas area also....dang it...I thought ALCOHOL kills this Cov19 bug ! J K
It is ironic ... you can bath in it but not drink it! Seems unfair.
I wonder if I would get arrested if I filled my hot tub with alcohol and invited 6 attractive ladies over to party....would we still need to "DISTANCE " ourselves to avoid contamination ? Of course , that would be a waste ! J K ;-)
i have 3 systems
DIN sockets were often poorly executed and introduced huge amounts of noise because of the gain needed compared to RCA phono circuits. Sometimes on cassette decks, the DIN input would add over 10db of noise essentially negating any benefit of Dolby B noise reduction!
I suppose that’s what happens when you try to fit too much audio info on a small socket. Good thing they changed that.
Me looking at the EU schuko plug while hearing you speak with that British accent: something's wrong here.
Me moments later when realising Portuguese is being broadcasted: ah!
Yes, the radio testing gives me away :)
If you listen carefully, you’ll hear even more: “Antena 1, Madeira”. Where are you from?
@@electronicsoldandnew from Porto. I'm in the middle of your primaluna video right now. I have that exact same amp, still strong after 14 years. Eheh. Lots of catching up to do, now that we are locked in. Stay home and safe!
You too.
Hi, are you South African
Madeiran born, but grew up and studied in SA. First Harrismith, then Pietermaritzburg, followed by Durban varsity. Where are you from?
Electronics Old and New by M Caldeira used to work for Etkinds in Kempton City ( Kempton Park ) in the early 70’s and sold B&W product, loved the product. What amazes me is how the style has not aged.
@@electronicsoldandnew Wow snap, i currently live in Harrismith and have been for the past 20 + years. Was born in Germiston and grew up in Estcourt
Me likey
😊
🇩🇿❤
too. many. ads.
Google Adwords must be exaggerating with all the people stuck at home.
Lovely unit, wanted one of these way back. I do have the slightly down market 1700 series, still very good , works well and good sound quality. flic.kr/p/8G1jD4
They’re all great sets.