Beomaster 2400 Type 2902 - Canada Project First Opened Up

I plugged this new Beomaster 2400 unit in and checked out the lights on it to see if any were burned out.  It turns out that all of the lamps are functioning.

 

As promised I opened up this new Beomaster 2400 receiver to check the components inside.

The Bass, Treble and Balance slider controls look to be in good shape.

The slider controls on this Beomaster 2400 are a different style than I usually see.  I have seen these before but they have a round bar for the slide control to travel on instead of the usual flat bar.

 

The black plastic bridge that holds the slider control contacts is different due to the round bar that it attaches to. As a result of that difference these controls don't have the problem of the broken contact mounts that typically require a repair.

Now to take a look at the Beomaster 2400 indicator lamps. 

First, the volume control lamps. I can see that one of these lamps has been replaced in the past.
So this Beomaster 2400 has been worked on before.

Here are the lamps for the Bass, Treble and Balance indicators.

The indicator masks for these controls were is good shape but you can see on the underside of the red lens caps that there is a lot of fading due to heat from the incandescent lamps.  I usually replace the original lamps here with cooler operating LED lamps.  These three lamps are always on when the Beomaster is not in standby and are not vital to any circuitry in the Beomaster.  They simply are powered on and off when the Beomaster comes out of standby and goes into standby.

The last group of lamps are for the FM tuning indicator, FM stereo indicator and the selected audio source indicators (Phono, Tape, FM1, FM2, FM3, FM4 and FM5). There is also a red LED lamp for the standby mode indication.

These lamps do wire into Beomaster 2400 circuitry and factor into the operation of the circuits they are part of.

Now the restoration can be planned and implemented.
I start on that tomorrow.

Beomaster 4400 Type 2419: Initial look at a local B&O Beomaster

A local B&O owner dropped off his Beomaster 4400 for restoration a while back. It is time to open this unit up and get started.

This is a nice and clean Beomaster 4400 unit. I'm looking forward to listening to it. Unfortunately at this time...it is not functioning.

It has the rabbit ears FM antenna and the clear, plastic FM preset cover intact. You don't often see a Beomaster 4400 unit with those.

This unit is pretty good cosmetically but it has some discolorization and cloudiness to the slider control lenses so I will need to order some replacements.

Here are the internal boards as I start to remove them.

Overall pretty good.  There is some expected dirt and grime but nothing bad. The next steps are to start cleaning and replacing capacitors.

Beomaster 2400: Restoration Project for a Texas Owner

There is just barely enough time to get in one more vintage Bang & Olufsen restoration project for 2019.

This is another Beomaster 2400 restoration. I have had quite a few Beomaster 1900 and 2400 projects this year so why not another one.

Let's jump right in and evaluate the starting condition of this Beomaster.

Cosmetically it looks very nice.

Since it is in such nice shape I decided to power this unit up and see what its status is with regard to lights and touch control switches.

I was pleasantly surprised that all of the touch switches work and most of the lights do as well. The Treble indicator light is burned out apparently.

Now on to opening the Beomaster 2400 cabinet up to get to the circuit boards inside.
For this restoration project I will be doing the usual replacement of electrolytic & tantalum capacitors, the cleaning of the slider switches and any other repairs I run into as I check out the insides of this receiver.

First I remove the door and panel for the tone controls and FM channel tuning.

Second is the removal of the Beomaster 2400 bottom plate.

Note that the Phono DIN plug is the 7-pin type. That means this Beomaster has (or supports) the circuitry for (wired) remote control of a Beogram 4004.
That is desirable in this case because the owner has a fully restored Beogram 4004 ready to use with this receiver.

Now for the removal of the touch control panel.

The bass, treble and balance controls have indicator masks that are in excellent condition. I will have to look closer but all three slider controls appear to be fully intact.

This version of a Beomaster 2400 has different and newer board to board connectors.

Here is the main body of the Beomaster 2400 after I have removed all of the other components.

I don't like trying to de-solder and solder electrical components in between the frame pieces of the cabinet. I prefer to remove boards and components from a unit and work on them individually.
This Beomaster 2400 is now broken down to where I can start recapping the main board.
I like to start with the most difficult task first and get it out of the way.

Beomaster 2400 Type 2902: Another restoration project begins

An owner of a Beomaster 8000 restoration I did last year sent me a nice Beomaster 2400 unit that needs some work. Today I was finally able to put it on the bench and check out what condition it was in.

The outside cosmetic condition of this Beomaster 2400 is quite nice. With it plugged in I can get sound from the FM tuner testing the Beomaster output with some headphones. I can see however that the Treble indicator lamp is burned out. In addition, the Bass and Treble controls do not work. The slide control knobs are loose which is a symptom of broken sliders.

As you can see, a handsome Beomaster 2400 unit. It didn't arrive with a remote control so I used mine to check that the remote control functionality works...it does.

Now it is time to open the Beomaster up. I know that it partially works so that is good. However, the problems it shows from the initial testing indicate that typical problems for this receiver exist.

The disassembly begins by removing screws on the underside of the Beomaster. I have circled the screws that I remove with red circles in the pictures.

This is an early production Beomaster 2400 unit. The Phono DIN jack is the 5-pin type of DIN jack. Later Beomaster 2400 units were fitted with 7-pin DIN jacks to go along with the added support of remote control functionality of the Beogram 4004 turntable. Bang & Olufsen produced a modification kit that included a 7-pin DIN jack and wires to add the Beogram 4004 remote control support to these early models.

Here is the schematic diagram from that mod kit.

We will decide later in this restoration whether this mod kit will be applied. Interestingly, there are 7-pin DIN jacks available for the Beomaster 2400 from later model Beomaster 1900 units. Because the Beomaster 1900 and 2400 share the same main board Bang & Olufsen started installing 7-pin DIN jacks on both the Beomaster 2400 and the Beomaster 1900 units...even though the BM1900 receivers do not have remote control circuitry. Swapping a 5-pin DIN jack from an early Beomaster 2400 with a 7-pin DIN jack from a later model Beomaster 1900 would not result in loss of functionality for either unit.

Continuing on with the Beomaster 2400 disassembly I loosened the rear panel for removal.

That step allows the bottom panel that was loosened earlier to now be removed.

Next is the removal of the tone control and FM tuning control panel. Two screws are removed on either end of the panel to allow it to slide out.

Now for removal of the bottom control panel (volume control and source selection).

With the control panels removed I can see the inside components of the Beomaster 2400. I spot some problems with the Bass and Treble tone controls as well as with the display indicator masks for Bass, Treble and Balance.

The indicator masks have started to deteriorate from the heat produced by the indicator lamps. I have seen this before on the Beomaster 1900 (which as I said before, is essentially the same receiver...minus remote control).

I have new replacement masks I can fix the deteriorating ones with. In this restoration I will also change the Bass, Treble and Balance display lamps to LED lamps which run way cooler and should not repeat this problem.

Be careful removing the little brass clips that hold the display mask to the slider bridge. If done wrong the lip of the brass clip can easily be broken off.  The ends of the clips need to be pressed inward then up as shown here.

The Bass and Treble adjustment sliders are loose and do not function. This is usually because small, plastic clips on the plastic slider bridges have failed. I can see that is the case here.  Martin Olsen produces replacement bridge parts to fix this problem so I will be installing those here.

To continue the disassembly of the Beomaster 2400 I need to loosen and remove the tone control and tuner control board followed by the removal of the three indicator lamp modules (volume, tone control and source selection).

Now all that is left is to loosen the large, main board so I will be able to get to the majority of capacitors that need replacing in this restoration project.

The FM tuner box (the shiny silver box) and the FM antenna jack must also be loosened.
Finally the main board can be lifted up for access to all of its components.

I can also get to the two reservoir capacitors easily now for replacement of those.

The initial evaluation is complete on this unit and the Beomaster 2400 is opened up where restoration work can begin.