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
Have ordered one now, seems like a VERY useful item in my hobbyI like the idea of supporting manufactoring in democratic countriesChristian
My re-capped M75 are my precious diamonds.
Menahem Yachad: "Sh1t, this meter does not show uF on the display, so now I'm in trouble how to "interpret" the results!" The EVB ESR meter shows the result in OHMS only. It does not show capacitance. For Capacitance, I have it on my Fluke multi-meter. Generally, on these cheap Chinese meters, the capacitance shown is so far off, as to make the reading totally worthless. For troubleshooting, you don't need to see the capacitance. You check the ESR in-circuit, and once you find a cap with high-ESR, you remove it. It's bad already, so what benefit is gained by seeing its capacitance? Anyway, you can't check capacitance in-circuit, you first have to desolder one leg of the cap. And are you really going to do that unnecessary work if the ESR checks OK? I so rarely bother to check capacitance in the real world of every day repairs - it's generally unnecessary. The ESR in OHMS is your PRIMARY trouble indicator.
"Sh1t, this meter does not show uF on the display, so now I'm in trouble how to "interpret" the results!"
The EVB ESR meter shows the result in OHMS only. It does not show capacitance. For Capacitance, I have it on my Fluke multi-meter.
Generally, on these cheap Chinese meters, the capacitance shown is so far off, as to make the reading totally worthless.
For troubleshooting, you don't need to see the capacitance. You check the ESR in-circuit, and once you find a cap with high-ESR, you remove it. It's bad already, so what benefit is gained by seeing its capacitance?
Anyway, you can't check capacitance in-circuit, you first have to desolder one leg of the cap. And are you really going to do that unnecessary work if the ESR checks OK?
I so rarely bother to check capacitance in the real world of every day repairs - it's generally unnecessary.
The ESR in OHMS is your PRIMARY trouble indicator.
So Menahem, capacitance reading I can use my Fluke? But how do I interpret the reading on the ESR display? What number on the display tells me if it's good or bad?
Brengen & Ophalen
Leslie:But how do I interpret the reading on the ESR display? What number on the display tells me if it's good or bad?
None of them! That's the "know how to..." part. There's no single answer. The EVB meter has a table printed on the front that gives approximate "good" ESR values for certain voltage rating / capacitance combinations of regular electrolytics. It's by no means complete, but it will give you an idea if a cap is probably out of spec. Nothing more. It will not tell you if that cap is actually a problem, or is still doing its job. For that, you will need to understand the actual circuit as well as the measurements.
--mika
Thanks Mika, guess I need a search on Google to learn more about ESR measuring.
Leslie,
The ability to determine a good/bad ESR reading comes with time. If you do a lot of repairs, it comes quickly.
You also learn to judge according to different manufacturers / series of the same uF/volts, and see the differences between models/series.
What would be a good ESR reading for a poor quality DingLing China cap, would be a bad reading for a Nichicon or Vishay of the same value.
It's not complicated, it just takes time, and the numbers fall into place.
Generally I work on equipment which has all Chinese caps installed, and I replace them with Nichicon / Panasonic / Vishay. So the ESR discrepancies between the originals and the replacements are immediately apparent.
The EVB is accurate, and it does its job the way it is supposed to. For me, it is the most used troubleshooting tool on my bench.
And for capacitance, use your Flukemeter - far more accurate than anything which comes out of China.
All capacitors above about 4000uF are "cheaters" - the datasheets always state +/- 20%. And 99% of the time, it's going to be -20% in the actual value of the cap. So if I need a 10000uF cap, I'll buy a 12000uF, and the actual value will be about 10000uF.
One caveat - the Flukes are not accurate for measuring capacitance below about 10nF. If you need to measure capacitance below that - very rare - you need a Picofarad meter - I have AADE's L/C Meter II, but I use it maybe only once or twice a month.
Thanks Menahem, useful information. Hope I can learn how to handle this ESR meter although I don't have any electronic knowledge, but you're never old to learn, right? Thanks again, hope we will meet someday to meet the master :-). Next week business trip to Sweden and hopefully Israel soon....
About a year after thinking up ideas and procrastinating I have finally come up with a speaker stand solution for my bedroom BS4500 and Fostex Pm0.4n monitors. The solution comes in the form of some used PA stands from a local second hand store.
Exactly why it has taken me so long to physically start this project is mostly due to lack of time but also the exact stand needs I wanted (aka design!). I have been interested in point-source listening for a long time (hence my interest and motivation to build my own BV2500s). Basically I want to reduce the reflections from structure around the speaker and most block-pedestal style stands would need some foam on the front to reduce this. While unsightly, these tubular stands will not require any acoustic trickery. Hopefully, once assembled, I can adjust the room and stands to improve aesthetics...
So to start, I need an adapter for my speakers so they can be connected. Secondly they are way to tall for chair-level listening, even in their lowest position. To remedy this, I have determined that 9.1875" can be removed from the posts.
Adapter:
At any rate... Off to the saw!
Beo4 'til I die!
Evan: So to start, I need an adapter for my speakers so they can be connected. Secondly they are way to tall for chair-level listening, even in their lowest position. To remedy this, I have determined that 9.1875" can be removed from the posts. Adapter: At any rate... Off to the saw!
Good luck with setting the saw with the required precision Evan!
Graham
vikinger: Evan: So to start, I need an adapter for my speakers so they can be connected. Secondly they are way to tall for chair-level listening, even in their lowest position. To remedy this, I have determined that 9.1875" can be removed from the posts. Adapter: At any rate... Off to the saw! Good luck with setting the saw with the required precision Evan! Graham
Oh yea! I forgot to mention my end milling post-process and then how I am going to verify with my giant vernier calipers..... NOT!
For those not using cad, 9.1875" = 9 3/16"
Perfection is expected!
Hi everyone,
I recently purchased a non-functioning Beomaster 2200 off eBay here in Australia. It is going to power by recently recapped set of Beovox S75 and replace my Beomaster 1900 (lamped,capped,rectified). I used to have a BC5000 and always found the sound of the BC5000 was a bit warmer and dynamic than the BM1900 so hoped after all the good comments on this forum that this BM2200 would offer a similar experience to the BC5000 or even better.
So the unit arrived from Canberra, packed exceptionally well and in good cosmetic condition. Initial tests showed we had lamps but no sound, the amps were powering up but there was power missing from one of the rails which powers the tone control,etc. This unit looks as though it had never been opened before. After discussions with Martin and some testing, it turned out most of the caps on the power module were either totally out of spec or not reading at all. A full recap of the power module and replacement of the two 5000uf 35v filter caps (which had leaked and expanded) with new 4700 50v caps (the best local alternative) and all test readings were spot on. For good measure we then recapped the two amplifier boards and checked idle currents which are at 1.1v.
The next stop was lubricating bass and treble pots with deoxit and rebuilding the balance pot which had dropped a leg. The volume pot these is a weird strap with a set of sliders attached to the back, mine was difficult to move and upon inspection it turned out the strap had broken at the join on the back and this meant the volume couldn't be turned down past about level 2 on the dial as the strap would bunch up near the rollers. So we stapled the strap together and applied some glue to hold everything in place, the volume now works fine but the strap is a little tight and hard to move. This will work as a temporary solution until a substitute volume pot arrives from Martin in a few weeks (shipping to Australia is sloooww).
I had to reassemble the BM2200 a few times, I would put the side panels on and then realise I had routed a cable incorrectly or a plug was stuck under the program switches causing them to stick or something else like that. These amps are an interesting design but a bit painful to disassemble. In the process I managed to lose one of the little switch covers for the speaker 2 on/off switch (Martin to the rescue again). That all out of the way and it was time to listen to some music.
I usually run my amps at flat (bass and treble at 0). At first turn on I was a little confused about the sound, it was closed in, I then realised the switch was set to Mono not Stereo and this affects external inputs as well as the tuner, with the switch set right its time for some listening.
Initial impressions were that the sound was every bit as good as the BM1900, The difference was subtle, not jaw dropping, I do really like the looks and design of this unit. The tuner seems to pick up signal better (one of my criticisms of my BM1900) and seems to give better channel separation. My BM1900 has had an issue since I got it where changing FM5 could affect the other presets - a faulty component somewhere, thankfully this amp doesn't do this which is good.
The amp has done a few hours work now and I am really warming to it, I started off playing compressed mp3's and the sound was good but not awesome, however when I got some vinyl spinning the picture started to paint itself. The sound is more dynamic and solid than the BM1900. There is a fair bit more power as well and when turned up, the amp doesn't fatigue at all.
I did note the lack of a loudness function which is in most of B&O's other amps from this period (BM2000, BM1900, BM4400) and found this a little weird, however the sound at low volumes does seem to keep a nice warm sound with a bit of bass extension so perhaps either a loudness function is already in the circuit and always turned on or the designers didn't feel it was needed.
The RIAA preamp in this amp also sounds a bit nicer than the BM1900, my Beogram 6000 has the quad preamp inbuilt and I have always preferred its sound over using my 4002 through the preamp in the BM1900, the BM2200 seems a bit closer to the sound from the BG6000.
Here is a pic of the inside before restoration, note the red filter caps, on many pics I've seen online, these are grey.
Here are some pics, first just after using Howards on the wood trims and polishing the metal surfaces with stainless steel polish, and the second of the amp in situ next to the S75's.
A wreck machine has come up locally so I may purchase this as a spares machine, I quite like this BM2200 so far and usually try to have a few spares of 'known to fail' components just in case.
Hope you enjoyed reading, I love these threads so thought it was worth sharing my experience :)Drew
Evan: The solution comes in the form of some used PA stands from a local second hand store.
The solution comes in the form of some used PA stands from a local second hand store.
You could have just gone to Best Buy.
Rich: Evan: The solution comes in the form of some used PA stands from a local second hand store. You could have just gone to Best Buy.
I actually used to own those stands! But sold them off with a pair of speaks about a year ago. I don't think that they would hold these speakers, pretty unstable with small monitors such as my Fostexen.
These second hand ones are much more sturdy. I don't think I'll lose any $ either, paid $30 for the stands, priced out extra material at $20. These are the stands I've been waiting for. All I need to do is invest some time standing in front of a mill and lathe.
Also, I think I like the studio/heavy duty look more. Studio monitors belong on studio stands.
Now all I need is the time to do this!
Evan: Rich: Evan: The solution comes in the form of some used PA stands from a local second hand store. You could have just gone to Best Buy. I actually used to own those stands! But sold them off with a pair of speaks about a year ago. I don't think that they would hold these speakers, pretty unstable with small monitors such as my Fostexen.
I've had speakers weighing 20 pounds on those stands with no issues. These days they're supporting dipole surrounds in the living room where the only thing B&O is an RX2 turntable.
You just don't want the cat jumping on whatever is mounted on them.
Broken drivers
Potentiometer mechanism on BM1600
//Bo.A long list...
Ricardo: Broken drivers
Ah, a project near and dear to my heart! Good luck! With your near infinite pool of patience I'm sure you'll do just fine.
Rich: Ricardo: Broken drivers Ah, a project near and dear to my heart! Good luck! With your near infinite pool of patience I'm sure you'll do just fine.
It appears to have been a success !
Here a some pix of the remainder of the repair process. All that remains is some cabinet cleaning and new frets. Final placement when its all done. But for now they are simply leaned against a set of Redlines plugged into the PizzaBox 5000 playing some Walter Wanderley off of my iTunes library.
Ricardo: Where did you get those 90° presses, just perfect for corner repairs, and I have a pair to do. And good job with the woofers, love this kind of repairs, most people give up on these.
Collecting Vintage B&O is not a hobby, its a lifestyle.
Søren Mexico: Ricardo: Where did you get those 90° presses, just perfect for corner repairs, and I have a pair to do. And good job with the woofers, love this kind of repairs, most people give up on these.
Quality Farm & Fleet many years ago. I orignally bought them to hold picture frames in place. I once had a small picture framing business as well as holding art canvas stretchers in place.
I think any good wood working place or perhaps an art hobby type store would have them. they are still around.
I have one I never use. Want it?
Recapped my RL 140's today. Some "high quality" and some "attractive priced" components. The treble seems to be a little bit more "clear" for the, while for the bass I do not hear much difference.
Before
The replacements
After
I've painted the stands black to match te new black speakercloth. Currently they are drying, pictures when finished will follow.
Wouter
Rich:I have one I never use. Want it?
Didnt see your answer until now Rich, thank you, but started digging into carpenters tools, and found some interesting tools for corners that can be used for bigger items also.
At the moment I am into building solar, nearly finished a 500 liter 5 m2 system with heat exchanger, as always in Mexico difficulties to get the right parts, and with that waiting times, until they arrive
After the RL 140's I recapped the first S75 tonight. What a wonderful speaker, such nice warm and balanced sound!
Beogram type 59xx has a little speed increase from 33 on halfway of record???
Strange....
blah-blah and photographs as needed
Check for a slipping cable, or if it is about the drop-point for a 45 record, then the 33/45 switch circuit.
Could also be the 33 poti.
Dear M75 Phase Link, wellcome to loose magnets club.
His brother, the M70 phase link, was a founding member of the club.
I'm starting to think that if you have a cone driver, get out the epoxy.
Yes, probably one cant go wrong in that as there is no evidence that any speaker with glued magnets cant suffer from that problem on their lifespan.
And those surroundings... On M75 is SEAS woofers, not SEAS in did think before... Ja kissan villat!
UPDATE: Did glue SEAS woofers, just in case, tought they seems to have different kind of glue...
Menahem Yachad: Check for a slipping cable, or if it is about the drop-point for a 45 record, then the 33/45 switch circuit. Could also be the 33 poti.
It isn't belt or poti, as speed is stable, only it increases a bit somewhere at landing point of 45. But isn't 33/45 switch circuit high/low type? Nothing in between? How could it be it...?
First check physical causes, like a belt, or dirt on a toothed wheel.
If not, then you have to check possible electronic causes.
Scope the 33/45 switch circuit , and see if the waveform signal jumps. If it does, then scope-check the surrounding circuit. If it doesn't jump, then the switch is not the cause, look elsewhere.
Troubleshooting requires looking in the "likely" and "possible" places.
You cannot say that "oh, the problem cannot be in this place", because then you'd never solve anything ;-)
Menahem Yachad: Troubleshooting requires looking in the "likely" and "possible" places. You cannot say that "oh, the problem cannot be in this place", because then you'd never solve anything ;-)
Yes, you are quite right.
I finally got around to opening up my S45-2's to put a bead of epoxy around the woofer magnets. What did I find? A previous owner had already had it done!
My S45-2's were my first B&O speakers (and second B&O purchase overall). I had purchased them off Ebay USA in 2008. Apparently, the magnet slip failure mode of S45-2 woofers was known at least that early.
Good for you then!
I love the S45-2 speakers too, but the M70 are just impressive, providing for what the babies just can't - great bass!
I haven't glued the magnets yet...
Jacques
And the M70 can get LOUD.
Thanks to Nick (Solderon), I just finished restoring a BeoCord 5000 - 1980's model - the Nak beater.
I was short of some parts, and he came through!
Yesterday my roommate snapped a pic of me hunting down a rattle in one of my A7's.... Time to institute regular scheduled bolt-checks!
Nothing like climbing inside your loudspeakers to give a sense of scale!
I started on my BM 3300 type 2953, when connected it goes correctly in standby, All function are there when choosing input, all lights are there, all volume lights are there "0" to "80", selecting FM it comes up correctly with volume at "30".
Remote function correctly.
Only problem is, I cant adjust the volume level, not on the panel and not with remote control, the volume level lights goes correctly up and down, but volume level stays the same. Bass and treble working, balance not working.
I found R 241 and R 441 set to "0" Ohms, adjusted these to 50 Ohms the volume got a little lover, readjusted to "0" and the volume is the same as before.
Before I rig an antistatic working space, does anybody know of this problem and an easy fix.
This BM has more different types of electrolytic caps than I ever seen before, all colors represented, black, blue, green, orange, violet and the old ROE.
You already know the answer! New caps, new potis.
After that, check the IC's which control the electronic steps for the volume. Vcc, volume-in and volume-out pins.
I've seen these fail a few times, but remember that those IC's won't function as designed, unless they have stable power, and THAT's the job of the decoupling caps on the Vcc rail.