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I agree that the tip of the stylus doesn’t look quite right (but is hard to tell from the pictures). You might want to try cleaning it in case it just has crud build up. There are many ways to clean a stylus (some good, others not so much). I usually start with a dry 5/0 artist brush and only progress to something more aggressive if needed.

After cleaning, reevaluate the condition of the tip. Search online for macro photos of styli for a comparison.

Martin:  In the first picture, is the cantilever skewing to the left an indication of a failing suspension?

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That was painful to watch.

Just curious… How many hours do you think that it would take you to repair just the “damage” that he caused during the filming of the video?  (i.e. fix the cartridge contacts from the sandpaper damage, etc.)

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GeorgeHatesFun wrote:

Is this a symptom of a trashed cartridge?

Possibly. Can you post some pictures of the cartridge? (especially the cantilever from the front, top and side)

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You might want to reconsider storing equipment in an attic depending on the temperatures that occur in your particular attic. I know that my attic gets above 120 Fahrenheit / 50 Celsius in the summertime. IMHO, this is too hot for storing equipment. I store my excess equipment either in my cool, dry basement or on semi-permanent loan to family and friends.

I’ve considered removing belts from the tape decks for long term storage. This may save the step of cleaning up the “goo” if the belt degrades that far.

For the lithium batteries… Whenever I replace the soldered-in batteries, I install a socket. This would make it easy to remove/replace the battery if needed.

As far as the equipment use affecting battery life, I think that it is dependent on the specific design. I’ve seen some designs where the battery powers the memory backup regardless of the power status of the equipment.

I’m also curious about people’s opinions about the “use it or lose it” when it comes to capacitors. I’ve read contradicting things on this subject (i.e. the subjective versus objective problem).

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Thank you Lee and Keith for making Beoworld the invaluable resource that it is.

Thanks also to anyone else that made Beoworld such a special place. It may have been through supporting the site with sponsorship, by other financial means, or by providing useful content and camaraderie.

Beoworld certainly makes owning vintage B&O equipment much more enjoyable.

I wish you the best of luck in selling the website. It would be a shame for this treasure trove of information to be lost. If a new owner can’t be found, is there a possibility of archiving the “entire” website somewhere? Something like the “Wayback Machine” (but without all of the broken links).

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markg2000 wrote:

A multimeter reading does indeed show negative polarity (the DC output voltage on the old unit is now indicating 19-volts, hence the need for the new 12v DC power supply).

You might not need a new power supply. If the power supply is unregulated, it will read “high” if there is not a load applied. You might want to take the multimeter reading again with the either the device connected to the power supply or a dummy load that simulates the device load.

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Rolf2 wrote:

I now am able to present the lid after a polishing treatment.

It looks like you made a significant improvement!

Rolf2 wrote:

I can still see scratches, but I am not sure, if they are on the surface (I cannot feel them), or maybe on the inside, or, third possibility, in the glass itself.

What you are seeing is most likely on the outer surface. The scratches might be ones that you originally didn’t notice or could be ones that you added as part of the sanding process. Being methodical with your sanding technique can help with identification. For instance, if you sanded “up and down” with the 1000 grit and “side to side” with the 2000 grit, the direction of the scratches gives a clue of where they came from. Scratches that are not up/down or side/side are probably original. The scratches left by a random orbit sander have a distinctive pattern and are easy to identify.

The other “problem” is that, with practice, you get better at finding and noticing the scratches. It is a curse. 😉

Rolf2 wrote:

I will give this practice lid another try, starting from scratch.

That is a good plan. Doing so should also help you answer your own scratch questions definitively.

Rolf2 wrote:

What would be interesting for me is, how much time it takes you for finishing such a work? How long do you need, e. g., for sanding in 4 steps, or for the machine polishing?

It all depends on the particular dust cover and how bad it was at the start. For example, I spent 4 to 5 hours on the BG8002 cover above before I took the pictures. I spent another 1.5 to 2 hours on it then next day to clean up the remaining scratches. Yesterday, I polished a Beogram 5500 cover (smaller, simpler shape) that started in better condition. This took about 2 hours total. Both of these jobs were done entirely with a random orbit sander.

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calania wrote:

I bought my speakers used and the steel wasn’t in the best shape with scratches and even some rust spots.

Yep, pristine Pentas are increasingly rare. Mine have their share of scratches and dents. I’ve considered sanding the stainless to a matte/brushed finish. This would make the flaws less noticeable.

There is also the option of painting. I’ve painted the plastic trim and bases (but not the stainless). One thing that I like about the paint is that it makes the speaker look more cohesive by not having so many different colors (shades of gray) and textures.

Painting the stainless seems blasphemous. It reminds me of a painted Delorean (the car). It may (arguably) look better, but is just isn’t a Delorean. 😉

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Looking good! It appears that you have found a pretty good match with the original fabric.

The fingerprints on the stainless is part of the charm of owning Pentas (at least that I what I keep telling myself 😉 ). I’ve tried many different things with varying degrees of success. I’ve settled on just wiping them down with isopropyl alcohol once they are installed in their final location and try not to touch them.

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Renaud wrote:

Assuming the transformer is correctly re-wired from 220V to 120V, is there anything else that would need to be rewired before the turntable can be plugged in using a simple plug adapter ?

I didn’t notice anything obvious. I’ve not done this myself so I can’t say 100% for sure.

I would NOT use a plug adapter. Cut off the EU plug and install a proper North American plug. You don’t want to get into the situation where the internal conversion to 110v is done and then the turntable is accidentally plugged into a 220v outlet. Bad things could happen from both a physical and liable standpoint.

Of course, following common sense and all local laws is heavily advised…

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B3OHACK3R wrote:

What exactly you’d like to connect there?

I’m not exactly sure. It just “seems” like something that might be useful. 😉 Being able to bit-bang from a Raspberry Pi would likely cover anything that I would want to play with.

B3OHACK3R wrote:

Each telegram contains a checksum. If a bit got flipped somehow (messages colliding etc) the checksum won’t match and the telegram is ignored or resent.

My question was related to how the retry strategy works. For example, which device (sender or receiver) initiates a retry? I’m not really looking for an answer here, but your statement of a “USB-serial chip that on the receiving side happily ignores any parity errors” got me thinking a bit. My experience is that 90% of code from most projects is (or should be) dedicated to faults and edge cases. This code is usually under-represented since 90% of the coders only want to work on the 10% of code that is NOT faults and edge cases. 😉

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I’m glad to hear that it worked out, but where are the pictures? 😉

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It is not obvious from the video since the connections are under the black transformer cover.

I happen to be working on a Beogram 5500, which has very similar, if not exactly the same, inner workings as the BG3500.

Here is a picture of the transformer connections

 

Here is the relevant part of the schematic

Notice the 110v and 220v connection diagrams at the bottom of the schematic. For reference, the transformer in my picture is wired for 110v.

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Renaud wrote:

Are you suggesting that the same transformer can be used for both EU and US models ?

It is fairly common for a manufacturer to use the same transformer inside equipment targeted for different power markets. Even though the physical transformer is the same, it is wired differently depending on the market.

If you are not familiar with electronics, you might want to have a qualified electronics repair shop do the conversion. It should be a simple enough job to keeps the costs low. It might even cost less (and be safer) than buying a quality voltage converter ;-).

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Did you mean to say “step up” converter (i.e. from 110v to 220v)?

I can’t help you with a converter recommendation.

However, have you considered doing a voltage conversion of a EU spec machine?

Based on a quick look at the service manual, it may be as simple as changing the lead connections to the main transformer, replacing the plug, and updating the “power label” on the back of the turntable (to indicate that the machine was modified). I haven’t done this on a BG3500 myself, but I assume that others have.

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Guy wrote:

Strangely I can’t help being disappointed that it wasn’t more of a challenge to fix!

LOL. I’ve had a similar feeling after getting something working with a full “recap/reflow”. 😉

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Rolf2 wrote:

Question: You are using a “Mini” buffer for the polish. In the Youtube video above the guy is using a “standard” sized buffer. Is there a specific reason, any advantages using a smaller one?

I like this “mini buffer” since it seems appropriately sized for the job. I have a couple of larger buffers and I would expect them to work just fine for most of the job. They would just be a bit less maneuverable. I also have a smaller buffer that is easier to get into tighter spaces, but I didn’t have the need. I could have done the job with the smaller machine, it just would have taken more time. I have all of the buffers since I also restore cars and boats as a hobby.

The deeper scratches are hard to remove. As you likely already figured out, polish will usually make a scratch less noticeable, but doesn’t really remove it. Removing a scratch is better described as removing the material around the scratch to the depth of the scratch.

Sanding is the most efficient way of doing this. But sanding leaves its own scratches. These scratches are removed with the next finer sandpaper, and so on until the scratches are shallow enough that polish will work.

I exclusively use a machine for this job since I don’t have the patience to do it by hand. I make my own ultrafine hook&loop sandpaper pads by gluing the ultrafine sandpaper to felt cloth and cutting it into circles to fit the backing plate. This is another place where the mini buffer comes in handy since it can be fitted with a backing plate that is similar diameter to the width of the sandpaper brand that I buy.

One tip for hand sanding is to alternate sanding directions. By changing the sanding direction by 90 degrees, it is easier to tell when you removed all of the scratches from the previous direction.

Marking the scratches with a sharpie can also be helpful. Sanding away the sharpie marks provides an easy to see indication of where and how much to sand.

A bit of soap in the wet sanding water helps keep the paper from loading up as fast.

Clean things meticulously between stages. There is nothing worse than picking up a piece of grit, introducing new marks and have to back up a step.

If you feel as if you just fell down the rabbit hole, it is because you have ;-).

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Another advantage to the tape is that it could make it easier for the next person that wants to recover the grills. Tape should be easier to remove from the plastic frames than glue.

I like to make it easier for the “next guy” that works on the equipment because it probably will be me ;-).

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I’m currently working on a Beogram 8002 and its dust cover needed some work.

Here is my setup.

 

This cover had some pretty deep scratches. I started with 1000 grit sandpaper. Here is a picture of one of the scratches after a light 1000 grit sanding.

 

I stepped through 1000, 2000, and 3000 grit sandpaper with an occasional rough polish to check on the progress. I had to make several loops through the 2000 to rough polish stages. Once it was “good enough” (i.e. I got tired of working on it for the day), there was a final fine polish. Here are some before and after pictures.

 

The cover is reasonably presentable now. I plan to do a couple of more loops starting at 3000 grit to perfect it. I also need to do some work on the inside of this cover. The turntable was shipped with the platter installed (and the suspension not locked down). The platter left some pretty nasty gouges on the inside of the dust over.

Rolf:  It looks like your cover is starting in much better condition. It should be a pretty straightforward job to perfect it.

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It has been a long time since I recovered a pair of Penta grills. I don’t recall the exact order that I did things.

The advantage of the tape is that the fabric is repositionable. Apply the tape to the plastic frames, press hard to “permanently” attach it, then remove the protective film on the other side of the tape. Drape the fabric over the frames/tape, stretch slightly, and LIGHTLY press the fabric onto the tape. The fabric can be repositioned and stretched to remove any wrinkles. After it looks good, “hard press” the fabric into the tape to permanently attach it. Trim off any excess fabric as needed to get the grills to seat properly.

The first time I did this I was skeptical about the tapes holding ability. My concerns were unfounded.

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