Beogram CD50 From North Carolina: New Cabinet Feet, Ready To Return Home

The new cabinet feet for the Beogram CD50 arrived this week.  Installing them and wrapping up the listening tests were the final tasks of this project.

I discovered a problem with the original cabinet feet crumbling and falling apart while I had the CD50 partially disassembled during the CD tray belt replacement.  It is common for these rubber feet to deteriorate at this point in their age. Here are the original cabinet feet removed.

Only one piece remained intact but it was soon to fall apart like the others.
Bang & Olufsen used the same type of cabinets on their Beosystem 5000, 5500, 6500 and 7000.
That time period was from 1983 (introduction of the 5000) to 1995 (final period for the 7000).
So eventually all of the components for those systems will likely need these same type of rubber feet replaced at some point. I guess that is why Beoparts carries them :-).

I ordered some sets of these feet from Beoparts as my own 5000 and 5500 system components could use new feet as well.

The new feet simply press into place. Removing the old deteriorated pieces is the hardest part of the replacement.

After the new feet were installed it was back to the listening room to resume the listening tests.

After about twenty CD plays I think this CD50 is ready to be shipped home.

A Pair of Beomaster 1900 Receivers for Restoration: Unit #2 Wrap Up

The second unit of the two Beomaster 1900 restoration projects is complete.

After letting the Beomaster 1900 play music through the night ...

...I was ready to reassemble the cabinet pieces.

I secured the Bass, Treble and Balance indicator masks back onto the slide controls

Then I fit the touch control panel onto the cabinet frame.
This can be a little tricky since the touch panel button actuators have to fit onto the button sensor posts.

Always check that all of the touch buttons are working before proceeding with the cabinet reassembly.

After the touch button control panel comes the tone control and FM tuning panel.
I applied some new Nyogel damping grease to the lid damper before securing the panel in place.

There are two rubber stops for the control panel lid to rest against when the lid is closed.

Those rubber pieces are always deteriorated and falling apart (if not already gone).

I made a replacement bumper pad with my 3D printer that fits where the original rubber pads were.

On the cabinet base plate I installed four new plastic cabinet feet that I ordered from Martin's Beoparts store.

The final piece was the smoked plexiglas that fits over the touch panel indicator lamps. I had removed it to polish it. It just slides back into place.

Now the Beomaster 1900 is ready for testing in a listening room.

Beomaster 4400 Type 2419: Final Reassembly and some final restoration tasks

This has been a marathon of a Beomaster 4400 restoration. Every time I thought I was ready for the home stretch some new problem would pop up.

With the testing out of the way this Beomaster has been playing constantly without any issues what-so-ever. So it is finally time to wrap this project up. Of course there were a couple of final repairs I had to make for this project to be complete.

The first was a known issue regarding the lenses for the slide controls. The old lenses were badly yellowed and foggy. I had already ordered a replacement set from Martin Olsen at Beoparts.

You can see how dark the background is in the picture above through the original lenses. The replacement lenses show what they should look like.

Reassembly of these components is a little tricky. The metal parts are very thin and probably had some special tool to mount them on the plastic slider at the factory. As such I found it very difficult to reattach them without any metal tabs breaking off. I ended up enlisting the aid of some very thin, double-sided tape (the kind used in modern cell phones) to put them back together.

The next issue was deterioration of the Beomaster 4400 cabinet feet. Almost all of the Beomaster 4400 units I have seen have feet that look like these.

You can see that there is also an accompanying rust problem.

This is the only part of the Beomaster cabinet that has any rust so I think the problem starts with the mounting screws of the feet.

I removed the old feet, sanded the rusty spots away, then spray painted the base plate (both inside and out).  I didn't want to lose the original wording and graphics on the cabinet base so I taped them off.

The rust is gone so I moved on to attaching the new feet.

The new feet have metal sleeves for the attachment screws so the screws don't compress the rubber as they are tightened. I threw the old feet and old screws away and used new mounting screws for the new feet.

The third and last issue I had to deal with was a broken FM tuning dial catch for the FM tuning slider.
All of these Beomaster 4400 units have a hard, brittle piece of glue that attaches the FM tuning slider to the tuning cord.

If you are careful with it the hardened piece of glue will remain on the cord and can be reused.
In this case it was too brittle and broke off.

There is not enough there to fit into the FM tuning dial catch.

The broken catch is always a blob of glue so I think the factory determined the position of the catch, set the tuning dial fork there and glued them together.  Whatever the type of glue they used was it does not bond to the slide control fork so it can be removed for service.

Over time however, those glue pieces break.

Looking for a solution that does not involve any permanent gluing to the slider fork I came up with using a small nylon washer and some epoxy to build me a new catch.

I marked either side of the tuning cord with a red marker before I removed that last remnants of the old glue piece.  That gives me the location for my new catch.

I used JB Weld fast drying, dark gray epoxy so I could easily see it.
I ended up having to cut some of the bottom part off because the catch was a little too big.
Note that this task is really something that should be done prior to having reassembled the Beomaster.
At this point though, I did not want to go through a whole disassemble and reassemble operation.

In the end my makeshift catch does a good job.

It fits into the tuning slider fork and the FM tuning slider operates the main FM tuning great.

Finally I could finish the reassembly of the Beomaster 4400 and get on with the best part...some listening tests.

Beomaster 1900 Type 2904: Cleaning, polishing and reassembly

For about a week since the last post this Beomaster 1900 has been sitting on the workbench playing music for hours on end. No problems surfaced during that time so with the new parts broken in I am ready to reassemble the Beomaster before going into the final stretch of testing.

The trickiest part of the reassembly has to be the touch control panel.
The copper, spring leads for the touch controls must fit onto corresponding posts on the Beomaster 1900 circuit boards. A trick Martin Olsen taught me was to install this panel with the Beomaster 1900 bottom cabinet plate still removed. That way you can inspect each touch control contact from underneath and use some tweezers or probe to maneuver the contacts into place.

I reinstalled the indicator masks for the bass, treble and balance slide controls at this time.
I also used some plastic cleaner and aluminum cleaner on the touch panel as I installed it.

The next piece to install is the other part of the top cover. The grooved section for the heatsinks and the access door hinge had a lot of dirt and grime from wherever this Beomaster was stored.

I cleaned it with mild cleaning solution and a couple of brushes to get into the channels.
The right side hinge of the access door was loose and came off so I reattached it with some epoxy.
Before reinstalling the base of the cabinet I gave the Beomaster a quick test to make sure all of the electrical connections were still good.

Finally I could install the cabinet base. This cabinet was missing all four of its feet so I used the replacement feet I recently got from Martin Olsen.

While the Beomaster 1900 was upside down I noticed that the Phono DIN jack is a 7-pin DIN connector.  There isn't anything wrong with that but the Beomaster 1900 will never utilize the number 6 and 7 pins of that connector. The Beomaster 2400 is the receiver with a remote control and can control Play/Stop functions of a Beogram 4004 via the 7-pin DIN. Except for the remote control the Beomaster 1900 and 2400 share the same circuit board so I guess Bang & Olufsen just started installing the same source connectors on both receiver models.

The Beomaster 1900 is all assembled again so I turned it over and started another play test session.

This week I will connect it up to my audio analyzer and make some measurements. After that I will hook it up to a Beogram and Beocord to round out the functional testing.

Beomaster 4400 (2419): Final Touches and Testing

While starting on the two Beomaster 8000 restorations the Beomaster 4400 has been playing away in my office for several days without a hiccup.  A final series of listening tests are in store for this Beomaster before I pack it up and send it home.

The owner of this Beomaster 4400 receiver has a pair of Beovox M100.2 and Beovox MC120.2 speakers. It so happens that I do as well. So while he may not hook things up like this we felt a nice final test on this restoration would be to spend a couple of days with this Beomaster driving my two pairs of speakers.

But first....
I have been test playing the Beomaster 4400 in my office with the top cover still off. That was so I could monitor the inside as I played it. I wanted to know immediately if the problem with the two main board resistors returned.  That was three weeks ago.  No such problem since and I have been using the heck out this receiver.

Now to the Beomaster cabinet. It turns out it had a very weak rear trim panel and it finally broke.  That called for a cosmetic repair.  I also noticed that the bottom metal cabinet plate had bad rust areas around the cabinet feet.

First the cabinet.
Here is the damaged cabinet piece dry fitted back in place.

For this type of repair I use a slow drying wood glue and clamp the broken piece tightly into place. That will cause excess glue to ooze out the break seam.  While it is wet I wipe all of the excess completely off.  Then I rub in rosewood sanding dust that I collect from some pieces of rosewood veneer I keep handy for these type of situations. The rosewood sanding dust particles darken the light color of the break seam.

There is still a scar but when the cabinet is resanded and treated with fresh oil (boiled linseed oil) it looks quite acceptable in my opinion. It also helps that the break is at the back of the cabinet and on the side.

We thought about substituting a spare Beomaster 4400 cabinet but this is a really pretty cabinet.

Another cabinet fix I tended to was the left front edge. The inner particle board had started to wear away.  It wasn't visible but I felt the amount of material was kind of thin and needed reinforcement.  I made a little mold and used some JB Weld gray epoxy to build the area up again.  It turned out quite nicely.

The last bit of cabinet repair business was the bottom panel rust.
Here is one side of the cabinet base. The screws that attach the feet to the base are rusted and areas all around the rubber feet have rust corrosion.

I was surprised the screws came out without any of them breaking.

Interestingly the bottom panel was the only place this cabinet had any rust.
My fix for this type of problem is to sand down the rust damage until all of the reddish brown rust is gone. Then I wipe away the dust and start applying a rust neutralizer.  I do three coats of neutralizer wiping away each coat about fifteen minutes apart. I leave the third coat on for twenty-four hours.  Then I lightly sand it again.

Now it is ready for some satin black Rustoleum spray paint and new feet.
Speaking of the feet here are the original rubber feet next to the four new feet I am going to install. The feet are about 16mm in diameter and 6mm high.

The new feet have a nice metal sleeve to keep the mounting screw from digging into the rubber.

Here is the bottom panel re-painted and re-installed with new rubber feet and new screws.

There is some visible scarring from the rust corrosion but this is the bottom of the cabinet and the corrosive elements have been neutralized. I feel good about the fix. I could not stand leaving the old feet in place especially with that corrosion going on.

I moved the re-assembled Beomaster to a spare room where I often do some additional listening tests.
That is one reason you can see a lot of wires under the MC40 B&O cabinet.

Speaker placement is (almost) everything when listening to music. I figured I would experiment with various speaker positions during this Beomaster 4400 test but sometimes it just sounds perfect the first time.

This was one of those cases.  The combination of the M100.2 speakers on the inside and the MC120.2 speakers just a little forward and to the side work amazing in this room.  I listened to music for about an hour so far (at around 60dB from 10 feet away).  The dynamics of the music are really good.  The next few days should be a lot of fun.