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
Thank you Menahem, will take your word for it, no experiments, the BM 2400 is PIB to work on
Collecting Vintage B&O is not a hobby, its a lifestyle.
Menahem Yachad: 25VAC is fine for +/-31VDC - remember that you've got big 5000uF caps, which ups the output voltage.
25VAC is fine for +/-31VDC - remember that you've got big 5000uF caps, which ups the output voltage.
Menahem, I am not sure, that is what you actually meant to say (it's not quite correct, anyways);
A multimeter will only show an "average" reading of the DC contents of any given measured signal content.It cannot change its reading fast enough to keep up with the mains frequency (and you wouldn't beable to read it out fast enough either).
Put a scope to the rectifier voltage instead and you will see, that the voltage does not increasewhen the filter caps are connected.Instead the caps will remove ripple and make the output voltage a more steady DC (filtering out AC)and it's this more steady DC that results in a higher DC voltage ("average") reading on the multimeter.First lesson in power supply circuitry.
Søren , check the D50 rectifier. If it's the original part replace it. It was slightly underdimensioned from factory andthis issue was only "rectified" at the very latest production individuals.
Check also the nearby fuse holder on the main board. I've seen cases where the contact pressure had almostdisappeared due to fatigue, causing both intermittent and permanent dropouts.
Martin
"Put a scope to the rectifier voltage instead and you will see, that the voltage does not increase when the filter caps are connected.Instead the caps will remove ripple and make the output voltage a more steady DC (filtering out AC)and it's this more steady DC that results in a higher DC voltage ("average") reading on the multimeter."
Better said than I did!
What do you know, I'm actually working on something. The entertainment system at the sauna cabin (Beomaster 900K type S290, as featured in my long running avatar) needed some maintenance.
The dial lights were out. When both of them are, it is more often than not caused by corrosion in the fuse holder rather than both of the bulbs being burned. There's a dedicated fuse, located apart from the others, that feeds just the dial lights. I have no idea why that particular holder always gets this green corrosion when the rest of the chassis is spickety span.
After a clean, there's light again. Just noticed that a reflector is missing from one end of the dial. I don't have suitable materials or tools to make one over here, so I'll just note it for the future. You can hardly tell it from the outside anyway.
While the cabinet was empty, I gave it a light sanding and applied some wood oil. "Jan 25 1965" stamped in the inside, so this radio is just 50 years old. Now good for another decade, I think
--mika
Just finished these, new surrounds new caps, new, well she forced me to it, and I need some goodwill for my BL/BM 5000 project
Rich:And I no longer have the worst frets in the world! Blah blah blah, blah blah ba ran
Dom
2x BeoSystem 3, BeoSystem 5000, BeoSystem 6500, 2x BeoMaster 7000, 2 pair of BeoLab Penta mk2, AV 7000, Beolab 4000, BeoSound 4000, Playmaker, BeoLab 2500, S-45, S-45.2, RL-140, CX-50, C-75, 3x CX-100, 3x MCL2 link rooms, 3x Beolab 2000, M3, P2, Earset, A8 earphones, A3, 2x 4001 relay, H3, H3 ANC, H6, 2014 Audi S5 with B&O sound, and ambio
DMacri:I'd call it a tie. Dom BeoVision Avant, BeoSystem 5000 (BM 5000, BG 5005, BC 5000, CD50), BeoSound 4000, BeoLab 2500, BeoVox S-45, BeoVox S-45.2, RL-140, CX-50, C-75, CX-100, 3 MCL82 link rooms, A8 earphones, 4001 relay, H3, and ambio
BeoNut since '75
Søren Mexico: Just finished these, new surrounds new caps, new, well she forced me to it, and I need some goodwill for my BL/BM 5000 project
Speachless...
blah-blah and photographs as needed
How did you manage to bribe for a South African hunting license for those zebras?
Menahem Yachad: How did you manage to bribe for a South African hunting license for those zebras?
No need Menahem, this is from a Mexican zebra, they change (shred) their skin every year
Soren, you made me laugh!!!
Currently sorting out a system for a friend of mine. I'm pairing up my BeoVox 2600 along with the BeoMaster 1000.
It turns out that my problematic 2600 has a misaligned woofer. Before I start selecting a pair of replacement woofers, I was wondering if any of you have an original problem-free SEAS woofer I could buy?
Here is the woofer:
Beo4 'til I die!
Can't you just take it apart and rebuild it? I know that's easier said than done, but in the long run, isn't that the best approach?
Rich: Can't you just take it apart and rebuild it? I know that's easier said than done, but in the long run, isn't that the best approach?
I guess I don't really feel like building woofers right now. But I suppose I could look a little more closely when I get home. After all, the woofer is misaligned and its not going back into the cabinet as is...
My options are:
I think the last thing I want to do is rebuild a woofer - another can of worms I'm not interested in opening at the moment
Hi Evan,
Back in 2010 I had a twelve inch Yamaha woofer out of an NS-690 that had a misaligned magnet. I sent it to The Speaker Shop for repair and they did a good job (it's still working fine). At that time The Speaker Shop was located in North Lima, Ohio but they have since moved to Savannah, Georgia. You might contact them and get an estimate for a repair. It may be less expensive than buying a replacement.
John
Evan,
I have an original. - But it's in Denmark.
Greetings from my second bedroom stereo laboratory -
2600 Update - I decided to just buy the woofer Martin had on hand.
Now my battle continues with the BM1000... All capacitors (except for the axials and those ridiculous dual capacitors at the left corner, out of frame) have been swapped. Now I have gone to power up the unit for a functionality check and the two red resistors in the right channel section have started smoking! Then I swapped the trimmer (crudely) and the resistors still get mighty toasty, even with the trimmer cranked to the max.
I'll add that the DC offset reading is a staggering 14.8vdc for the right channel and 13.4vdc for the left.
Thoughts?
sonavor: Hi Evan, Back in 2010 I had a twelve inch Yamaha woofer out of an NS-690 that had a misaligned magnet. I sent it to The Speaker Shop for repair and they did a good job (it's still working fine). At that time The Speaker Shop was located in North Lima, Ohio but they have since moved to Savannah, Georgia. You might contact them and get an estimate for a repair. It may be less expensive than buying a replacement. John
Thanks for the info, John! Too bad they moved so far away from me! I'm sure the distance wouldn't matter any way.
For this particular project I am going to skip rebuilding the driver. However, I should still get the quote, I am curious now..
Evan
Most of those old fat carbon resistors are so far out-of-spec, it's not even funny anymore.
While I'm not going to speak specifically for the BM1000 - I've never worked on one, I can tell you that I regularly swap out at least 50% of those resistors on other B&O machines of a similar age.
That's probably your problem right there.
Replace them with Vishay PR03 for the big ones, and PR02 for the smaller ones (ex-Philips BC Components).
Also check the bias current resistors - replace with Vishay MRA-05 (previously known as Mills)
Menahem
The new trimmer seems to be a 5K component, which makes me assume that this is a type 2316 or 2317.
If you measure the DC offsets before the output series capacitors (the large ones you call doubles - but theyare in fact just separates), the offset is about right.The amps supply is 30V and it's not a dual supply so 50% of the supplied voltage on the center rail (midpoint) is correct.If you measure AFTER the series capacitors - they are both bad.Smoking emitter resistors points to a too high current flow through the output stage transistors.This could be a problem with the idle current circuit or the output stage itself.In your case, where the DC offset is not too far off, I doubt it's an output stage fault - but I cannotrule it out completely, so check both.Check the NTC too. I've seen one or two go open circuit.Note that the voltages stated in the schematics are negative to ground.That was common at the time, maybe a left-over from valves.Martin
Dillen:Evan, The new trimmer seems to be a 5K component, which makes me assume that this is a type 2316 or 2317. If you measure the DC offsets before the output series capacitors (the large ones you call doubles - but they are in fact just separates), the offset is about right. The amps supply is 30V and it's not a dual supply so 50% of the supplied voltage on the center rail (midpoint) is correct. If you measure AFTER the series capacitors - they are both bad. Smoking emitter resistors points to a too high current flow through the output stage transistors. This could be a problem with the idle current circuit or the output stage itself. In your case, where the DC offset is not too far off, I doubt it's an output stage fault - but I cannot rule it out completely, so check both. Check the NTC too. I've seen one or two go open circuit. Note that the voltages stated in the schematics are negative to ground. That was common at the time, maybe a left-over from valves. Martin
Menahem Yachad:Evan Most of those old fat carbon resistors are so far out-of-spec, it's not even funny anymore. While I'm not going to speak specifically for the BM1000 - I've never worked on one, I can tell you that I regularly swap out at least 50% of those resistors on other B&O machines of a similar age. That's probably your problem right there. Replace them with Vishay PR03 for the big ones, and PR02 for the smaller ones (ex-Philips BC Components). Also check the bias current resistors - replace with Vishay MRA-05 (previously known as Mills) Menahem
Well, I shalln't say, that they haven't been replaced by dual capsat some point - they are not in your photo - but the original capsare separate (= conventional) caps, just with three pins, where the third pin is for mechanical support only.You can replace with modern caps and leave the third (unconnected) solder pad empty, just remember to get the polarity right.
I made my BM 1000 type 2317 some time ago, here
Dillen: Well, I shalln't say, that they haven't been replaced by dual capsat some point - they are not in your photo - but the original capsare separate (= conventional) caps, just with three pins, where the third pin is for mechanical support only.You can replace with modern caps and leave the third (unconnected) solder pad empty, just remember to get the polarity right. Martin
This was the best news I've gotten in a long time!
I replaced them last night along with a few remaining items. The biggest change was the new woofer, I also re-cabled and re-terminated the speakers. I plugged it in around midnight last night and listened for about an hour, but had to keep it at a reasonable volume. To say the very least, the system sounds incredible. I can't wait to go listen a little louder during lunch
I've just put this two-way BC2300 back together after an overhaul. I bought it on eBay.de with 'faulty doors'. It was shipped in the original packaging and I reckon it must have been dropped from a great height (by dhl) at some stage! With the cold weather and age of the plastics the damage inside was quite bad, so I spent several days 'aralditing' the chassis back together. Then replaced the door belt, re-seated the door wire and put it back together - everything works well! It was also a good excuse to get my BL4000s out of their box and test.
testing...
Mmm. Beocord 5000. 'Got two of those, both working!
Jacques
three here, looks like led mods do not work on control swithc section...
I haven't tried LEDs at all. I sort of dislike them on these oldies. You know, I have 50 year-old hifi devices that still have their original bulbs... Careful transport is everything here.
I'm sure Rudy (Beolover) can advise.
Main problem is that solenoid for recording does not have strength to operate slides on the circuitboard.
The solenoid has the strength.
Unless there's a short in the coil winding, there should be no change in its performance.
Perhaps the plunger is sticking inside the tunnel, or the capacitor which provides the oomph is dead.
ORL3? Slideswitch was sticky, but now it doesn't stay on...
Um, should read manual..
Anyway, what is THE right method to assemble top flap spring?
Why did you disassemble it in the first place? I didn't, so I can't help.
Did not realize it is so dificult. It is on the place but was not easy, so thats why I ask.
I *finally* got around trying to fix my Beomaster 7000's tuner and my Beolink 7000.
The BM's tuner went silent already over a year ago when I was trying some re-capping to improve the tuners workings. I finally found a dodgy soldering joint which brought it back to life. I enjoy listening to radio while working on something else, and it's nice to have it back. Eventhough I must say that it's almost continuous flipping thrue channels to avoid ads and bad (modern) music!
Today I had a look on my Beolink; it had it's batteries gone flat over a period of non-use (mostly the time while the BM7000 was not in use due to the tuner fault) and it wouldn't keep charge anymore. Also while in charger the two-way IR didn't work anymore. I had repaired it once before (replaced two electrolytic caps around the IR parts) but I had not replace the two small SMD caps under the shield (as I couldn't then figure out how to get the shield off - also I had never worked on SMD parts at the time and didn't want to risk damading the board). It had worked fine for a while but clearly it was now time to get all those caps replaced. Sorry for not having pictures, but I have now assembled the BL and it's working again. I replaced the Ni-Cd batteries too and I am now giving it a first-time charge.
I hope to have gained some more years of life for the BL7000, it's surely a device I wouldn't like to open again and I just dread the thought of doing any more disassembly of it!
I am glad to have my 7000-system working again and I must say I love it