[auric]

You can hear Peter Ledermann talk about B&O cartridges here: https://www.youtube.com/watch?v=F65mODzn4Gk

B&O portion starts at 20 min mark.

Here is a tour of his factory:

[auric]

Your other option is to have a MMC4 rebuilt:

In the US:
https://aminaaudio.com/cartridge

Here is a video of someone who tried the service:

You can also get it fixed in Germany:
https://www.tonabnehmerservice.de/en/About-us-oxid/

[auric]

Check the fuses behind the cover where power cord goes into the unit.

But always inquire why the fuses blew in the first place!

[auric]

You could have the inputs swapped with the outputs. The din connector carries both inputs and output signals for instance in the case of interfacing with tape deck.

Here is the pinout of the aux Din connector (top diagram).

Use a meter and verify that RCA plugs go to pin 3 and 5 of the Din connector.

I have a 9500, taking line level inputs from non – B&O is not a problem.

[auric]

There may have been two different versions of cassette mechanisms for the BC 8000… This was the case with later versions as the series evolved.

The two mechanisms have different belt configurations. beoparts-shop.com has the right belts and parts including the pinch rollers! Check with them.

While you have the unit open, you may as well change the belts for the doors as well since they are quite old by now.

[auric]

I haven’t seen one in the flesh.

Here’s a video of the restoration program: https://www.youtube.com/watch?v=c9f6hXYk8ac&t=71s

You can email the company featured.

[auric]

Ken:

There are several screws you need to remove in addition to the 3 across the front ledge of the unit.

Flip the back cover over the rear connectors up. There is a screw in the right corner. Then there is a screw on the right side of the cover that holds a long cosmetic piece in place. Once you remove this screw shift the plastic piece and it will slide off. Beneath this piece are several more screws that hold the top cover in place. Once you remove all of the screws along the back, the entire top will flip open.

There is a steel rod behind the back lip just under the top cover. It runs along the length of the unit. Remove this rod and insert it into the a slot on the left side of chassis to the right of the transformer. This will prop the lid open and allow you to work on the unit. Its like the steel rod that props open the hood of your automobile.

Remove any CD or cassette from the unit and close both doors before attempting to take the unit apart!

[auric]

Would be wonderful if you can make them available!

Your joint work is much better than B&O 4000c recreation wood trim joint.

I’ve seen many 400x with banged up corners. This would be a great fix/upgrade!

[auric]

This is beautiful work Christian!

[auric]

Gnab:

Which part of the case did you crack?

The 8002 uses a completely different platter, different stylus and tone arm than the 8000. 8002 platter has no rubber ribs.

Derek

[auric]

Gnab:

I’m assuming the bottom cover of the turntable is installed when you are doing this so that the inner chassis is actually allowed to suspend?

There are no parts between the platter and the sub platter. The ribs of the platter rests on top of the sub platter.

Derek

[auric]

Gnab:

It’s hard to tell but from the picture but are the transport locks screws fully released?

The screws should be loosened.

The metal discs should be slid into their open position and then once release the screws should be tightened all the way down so they are not protruding above the discs.

Derek

[auric]

Hi Gnab:

You can see it at the bottom of the bearing in your picture and it looks intact. There is supposed to be a slight dimple because the end of the shaft of the rotor is pointed and rotates on top of it.

Excessive force possibly deform the plastic?

It’s one of the few parts that I can think of that can account for the height difference.

The other thing to check is that the hooks that suspend the inner chassis from the leaf springs are in fact original and not deformed. Check all three for equal length.

If you can’t find it on Beoparts, maybe Martin can help here.

Derek

[auric]

Hello Ganb:

The tip of the spindle bearing sits on a circular piece of plastic like a puck at the very bottom of the bearing. Usually what happens is that people ship the turntable with the platter installed rather than separating it. During shipping the platter slams against the bearing pushing the tip of the bearing into the plastic. The plastic puck is hard but brittle, slightly soft kind of like a plastic cutting board material.

Does the motor drive pan freely rotate or does it rub the bottom of the sub chassis when it rotates? If the the motor spins freely its probably fine.

You can try to replace it. Beoparts carries parts for the 8000. There is a hole on the underside of the brass bearing that you can use to push the plastic puck out.

 

Derek

 

[auric]

Have you changed the electrolytic capacitors C201, C202, C203, (and corresponding on right channel)?

There is also a 10uf cap inside the can.

 

Derek

[auric]

Dave:

Check for cold solder joints. There are lots of them on that machine!

CDX runs very hot. Possible, after warming up joints expands and momentarily curing poor connections.

Derek

 

[auric]

Hi:

There is a short video interview of Axel Schürholz plying his craft. Some of the footage shows his approach:

Derek

 

[auric]

I have added a PC board pin type battery holder for the CR240 for my BC9500.

Something like this: https://www.digikey.com/en/products/detail/mpd-(memory-protection-devices)/BS-2450/2439475?utm_adgroup=&utm_source=google&utm_medium=cpc&utm_campaign=PMax%20Shopping_Product_Low%20ROAS%20Categories&utm_term=&utm_content=&utm_id=go_cmp-20243063506_adg-_ad-__dev-c_ext-_prd-2439475_sig-Cj0KCQiAwvKtBhDrARIsAJj-kTgQ1PRRQ-jG3MJNQ-8cw_m-ioEObZWFzUCJiz59GgpVyc1ockdgeakaAu5OEALw_wcB&gad_source=4&gclid=Cj0KCQiAwvKtBhDrARIsAJj-kTgQ1PRRQ-jG3MJNQ-8cw_m-ioEObZWFzUCJiz59GgpVyc1ockdgeakaAu5OEALw_wcB

Then it allows you to use normal button cells without desoldering in the future.

Be very careful when desoldering lithium batteries. Please wear safety glasses. Any leaking residue can cause a nasty “bang,” with lots of smoke if the it gets on the soldering iron tip.

 

 

[auric]

Christian:

They are available here:

https://www.electronicparts-outlet.com/en/integrated-circuits/4688-mullard-fch131-dual-4-input-nand-gate-with-rc-dip14.html

https://www.electronicparts-outlet.com/en/module/iqitsearch/searchiqit?s=FCH+111

FCH131 is a 4 input Nand Gate. Can you use a 7420?

FCH111 is a 8 input Nand Gate. Can you use a 4068?

Those are much cheaper if they work. I didn’t check the pinouts and operating parameters.

 

Derek

 

 

 

[auric]

Hi Guy:

I would recommend replacing all of the belts while you have the unit open.

I’m finding that the plastic parts on the 1990s B&O are becoming very brittle over time. The plastic is literally crumbling apart and nearly impossible to repair with super glue or epoxy. The plastic parts that receive the threaded screws are particularly suspect. I live in North America and I’m not sure if it is a climate thing.

It’s a risk every time you open the thing.

Get it all fixed and done with and hopefully it will be good for another 20 years.

Derek

 

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