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Wednesday, August 22, 2018

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.


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