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Congratulations! It is good to hear that another BM6000 has avoided being parted out.
I might end up parting out my dead-CPU BM6000. As of now, it needs a CPU and a volume motor. It is kind of a shame since it is fully restored otherwise (reflowed, recapped, sliders/switched cleaned/lubed, FM aligned, LEDs rebuilt, etc.). The cosmetic condition of the machine (~5/10) is such that it would be cost prohibitive to fix (i.e. the parts would cost more than the fixed receiver is worth).
Glitch
If anyone has removed the control panel I would appreciate knowing precisely how you were able to do so and what tools you used.
Yep, the description in the service manual could be improved.
What I do is loosen the two screws on the back and put the upper panel into the service position (i.e. open it like a clam shell). This will give you access to the three clips for the control cover. Using a medium size straight slot screwdriver, move the outermost clip just enough to release it while pulling the aluminum cover forward. Don’t deflect the clip any further than you need to because it WILL break if you bend it too far. After the lip of the outer clip is released, do the same for the middle clip. Repeat for the last clip. The first clip will be the most difficult to get free.
Glitch
You are most likely triggering the amp FAULT circuitry, which puts the unit into STBY.
Verify the polarity of your voltage (and indirectly current) measurement.
Glitch
Based on your earlier descriptions, the “no keyboard” issue pretty much “had” to be broken traces. It is interesting to hear about where and how the breaks occur. Many times it is due to a stressed or warped circuit board.
The “no signal strength LED” issue is (most likely) either an open circuit between Board-8 or Board-6 and the LEDs on Board-2, or the trim pots on Board-8 being out of adjustment. It could also be a solder bridge or a number of other self-inflicted issues. I’d start by checking for cold solder joints on the edge connectors and measuring for continuity between the signal origins and destinations.
As far as the FM trim pots (Board-8), you might to check out this thread: Strategy for Changing Capacitors and Trim Pots on FM Tuner. My experience is that the settings on the FM board are pretty robust if all you want is to receive strong FM stations with poor sound quality. The settings are very sensitive for a properly aligned tuner with good sound quality and reception sensitivity. The odds of properly aligning the FM without measurement equipment are pretty much nil.
Setting the Tuning Voltage with 8R44 and 8R46 will likely fix your tuning range issue. However, it these are far enough out-of-adjustment to give you the described symptoms, you probably have many other FM alignment issues.
Glitch
With either the “stacked Penta” or “stacked BL200” you will need to figure out how to route the wires through the amps. The wire routing might be the most challenging part of the project.
I’m looking forward to seeing pictures of whatever you build.
Glitch
I’ve always thought that it would be cool to “stack” two amps at the bottom and bi-amp the Pentas. I don’t think that they would sound much better, but I think they would look better being 15cm taller. 😉
Glitch
I would try the “impact” method before WD-40. You should be careful with any oils or solvents (even water) with B&O equipment. I’ve had more “unexpected” reactions from the finishes on B&O equipment than any other equipment that I’ve worked on.
I like to use “hook tools” to gently lift the platter from the bottom (versus inserting something and prying).
Glitch
Could maybe soak the spindle in WD-40 and hope for the best
Something like WD-40 should be used as a (very) last resort. Try heat instead (carefully). A hair dryer might be enough. Also, try to pull perfectly straight. Any tilting could case it to bind.
Glitch
What kind of modernization were you thinking?
Anything from duplicating the basic stock functionality (on a modern CPU) to something that would operate similar to a Sonus device.
I’ve already started on creating a two-way, RF-based remote control.
I’m curious about what what kind of functionality that others would consider important. Integration into modern B&O networks? Integration into other networks (Matter, Spotify Connect, AirPlay, etc.)? Would anyone even bother with the BeoSystem 6000 generation of equipment if it was updated?
Glitch
Thank you for the links.
I did a quick search but didn’t notice any follow-ups after the initial thread (a year ago). I wonder how much interest that there is in modernizing equipment of this era.
Glitch
I meant if anyone who can write 3870 assembler code and wants to re-create the functionality of the original program, as you are doing with a modern processor, then the piggyback CPU would be available.
Anyone that would want to do that is far more hardcore than me. I did that kind of stuff back in the early eighties. I don’t think I’ve ever nostalgically reminisced about those times, thinking of them as the “good ‘ol days” ;-).
When I was writing the re-CPU software, I kept thinking to myself that it would have taken months to write the assembly code that I was able to crank out in a few days in a high-level language.
BTW someone else has already been through the process of making a plug-in replacement for the CPU, using a PIC processor. It would be good to see a pooling or resources for anyone else who might be interested in reviving a BM6000.
I wasn’t aware that anyone did a re-CPU of a BM6000. I read of a guy that did a re-CPU(s) of a BM8000. I think he based that on PICs. The thread was titled something like “BM8000 brain transplant”.
Do you have any links to the BM6000 PIC project?
I don’t think that I would be able to do what I planned with a PIC. Every time I revisit the “wish list” for the project, I feel the need to use a more powerful processor.
Glitch
I might be interested in the CPU(s). It is not clear to me what you mean by “rewriting the original program”. Can you elaborate more about what you were thinking?
I’ve already started a project to re-CPU my broken BM6000. I’ve built a rough prototype with a modern CPU. I’ve written software to perform the basic functionality (i.e. buttons, displays, volume, FM, etc.). This software also includes main board debug capability. I was working on adding remote control communication and Datalink communication when I got sidetracked by other projects.
I then got another “parts” BM6000 which had a broken volume motor. I scavenged the motor from the BM6000 with the bad CPU to fix the “parts” machine. This pushed my re-CPU project from the back-burner to off-the-stove.
Re-CPU-ing the receiver opens up many possibilities to integrate the BeoSystem 6000 with modern audio networks. I have a dozen or so ideas so far. I have even implemented a couple of them on my prototype setup. I hope to get back to this project someday. I’ll need to find a replacement volume motor to make my prototype bench viable again. Do you happen to have a spare volume motor?
I’ve also been toying around with a more ambitious BM6000 project than the re-CPU one. I wouldn’t need a volume motor for this, but it would take significantly more resources to complete.
Glitch
The extra wires are most likely used for signaling (turning on the Penta amps) and data for the displays. My best guess is that you currently have either one or the other working. A four pin cable may enable full Speakerlink capability. Unfortunately, I don’t know exactly what that entails and if the version of the Pentas (1, 2, or 3) makes a difference.
Hopefully my answer will hold you over until someone more knowledgeable replies. It may be helpful for others if you provide the “type numbers” of your particular equipment.
In general, if you are happy with how your system is working, you don’t “need” new cables. You might get some added functionality if you do upgrade cables.
Glitch
I am a relative newcomer here (~6 months) and not a “paying” member, so I’m not sure if my comments will carry any weight. I’ll post anyway since it might provide an alternative point of view…
I considered paying for a membership but ultimately decided against it. My impression is that the membership provides three things: 1) Entry in the prize draw, 2) Access to the manual scans, and 3) a “rank moniker” by my user information. I’ll address these in reverse order…
3) Titles don’t mean much to me so this wasn’t a consideration.
2) Access to the manuals was my primary consideration. However, it is not clear what is in the Beoworld manual library and if it any different than what is available (for free) elsewhere. I considered paying for a membership just to see what is there, but decided not to, mostly because I prefer original paper manuals. The library would provide some benefit even if I plan to purchase a paper copy. It would show what is included in the manual (i.e. full adjustment procedures versus just a schematic) before purchasing. The other use I have for the manual library is to be able to reference a manual (for equipment/manuls that I don’t own) in an attempt to help other members debug their equipment. Perhaps as part of the “membership sales pitch webpage” there could be listing of the available manuals and an example of the scan quality.
3) The prize draw was actually detrimental to my decision to buy a membership. When I researched the prize draw it seemed suspicious. It seemed to be “too good to be true”. The prizes were too nice and too numerous. It also seemed that “the regulars” were winning a disproportionate percentage of the prizes. There seemed to be a “good ‘ol boy club” vibe to it. I wondered if the silver member’s fees were being used to subsidize the gold member’s prizes. Lee’s post at the start of this thread did a lot to explain my misguided observations. The quantity and quality of the prizes were due to Lee’s generosity in heavily subsidizing the draw. The familiarity of the winner’s names was due to the decrease in the number of gold members (i.e. most of remaining gold members are active, long term members). Regardless of this epiphany, I hope that there remains an option (preferably anonymous) to support the core operation of the site independent of the prize draw.
I want to thank Lee, Ken, and any others that keep the site running. I know that it is a grueling, thankless job. I hope that I’m able to do my part by “paying back” those that helped me by helping others. My goal is to be able to “pay forward” with advice in case I need help sometime in the future.
I hope that people don’t lose sight of the idea that the site’s most valuable assets are the information in the posts and the camaraderie of the interaction with the other members.
Glitch
quattttro: Have you made any more progress?
I revisited my BM6000 that doesn’t power-up properly. I was able get it to work with a known working good CPU from another BM6000. Now I’m very confident that the original CPU is bad. With the bad CPU, I observe two different (pseudo-random) behaviors when I plug-in the receiver. The first is a “:.” display, the second is a “.” display with the main amp rail relay kicking in.
Glitch
The reverse shot shows another piece of equipment I don’t recognize, underneath the Cedric Hartman lamp (which I do recognize: oooh, lamps!-). (“View Image” in your browser to see full-size.) Maybe a mixer, thus this is the mansion’s “music room”?
That looks like a guitar amp. Maybe a Mesa Boogie Lone Star Special 2-Channel 30-Watt 1×12″ Guitar Combo?
Glitch
can you tell me where the “lower display connectors” are found? Do you mean in the lower board of the two, or is it found in another place than where the displays are mounted?
A better description of the location is on the bottom cover of the speaker. This cover is the access point to the crossovers. There is a round 8 (or 9?) pin connector on it. You will see the wire connections that I’m talking about if you remove the bottom plate.
On my Pentas, the wires are small and don’t have any strain relief. The other end of the cable (by the displays) has a better connection (crimped versus soldered)
Glitch
It is good to hear that the main problem was an easy fix ;-).
It is normal for the two BF858 transistors to run a bit warm. Based on the discoloration on your circuit board it looks like the amp was pushed pretty hard at some point.
I don’t use the displays on my Pentas, but I have noticed that the wires on the lower display connectors have a tendency to break.
Hopefully fixing the displays will also be easy for you…
Glitch
I assume it worked before the recap?
Post some pictures of the top and bottoms of your boards. Someone might be able to spot the problem visually.
Glitch
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