Beomaster 2400 Type 2902: Recapping the main board and the volume control board

I completed the capacitor replacement on the Beomaster 2400 main board and volume control board. This included replacing the reservoir capacitors and the idle current adjustment trim pots for both channels.

The Beomaster 1900 and 2400 receivers are not my favorite units to replace capacitors on. They are very compact and low profile which make things a little cramped inside. Unlike the large Beomaster 8000 these smaller Bang & Olufsen receivers do not have easy accessible and removable circuit boards for working on.

Here is another picture for the Beomaster 2400 before the main board recapping.

You can see there are a lot of capacitors to change out. About eighty capacitors out of the ninety-nine total I will be replacing.  I can't easily disconnect the main board from the rest of the Beomaster 2400 to remove it for recapping as it has several hard-wired connections to the transformer and power supply.  On a Beomaster 1900 one time I removed everything from the cabinet chassis but that still made maneuvering the board awkward as I had the weight of the still connected transformer to deal with.

Since then I like to disconnect the FM tuner box, reservoir capacitors and heatsinks so I can switch from front and back of the main board while recapping.

I remove a couple of solid wires to the transformer to avoid breaking them while working on the main board.

After that it is a careful and tedious ordeal of desoldering and soldering while switching from the component side of the board to the trace side...back and forth.  This is another picture of the main board after the recapping work was completed.

There was one 10uF, 63VDC capacitor under the metal shield box for the remote control circuit.

I usually replace capacitors with values of 4.7uF and smaller with WIMA MKS capacitors.
An exception is if the WIMA won't fit well as with the two small 4.7uF capacitors on this small B&O adapter board.

This picture shows the two Beomaster 2400 idle current trim pots after I replaced the originals.

When installed back in the cabinet frame the emitter resistors are difficult to attach probes to for making the idle current (or no-load current) adjustment. While I have the main board in service position I like to make sure the leads on the emitter resistors are long enough on the trace side of the board to clip measurement probes to.

This picture shows the +15VDC supply reservoir capacitor after the recap. I used a little bit of Aleene's glue to secure it in place.

The two large 5000uF reservoir capacitors are kind of a pain to change out on these types of Beomaster units. The original capacitor terminals are soldered together as well as all of the connected wires.

In my replacement reservoir capacitor assembly I use small terminal connectors to attach the wires to the capacitors and the two capacitors to each other.

That is a more secure connection and makes future desoldering of the reservoir capacitors easier.

The small volume control board only has six small capacitors to replace.

That leaves one capacitor in the FM tuner box to replace and a few capacitors on the tone control and FM tuning control board. Then the recap work will be complete.