You just need to replace the bulbs. The sliders actually move plastic films in front of a bulb - not as high tech as it looks! These are not the simplest machines to take apart as there is a lot fitted into a small box! If you have done similar work before, it is quite simple but I would get someone else to do it if I were a novice! 

Welcome to Beoworld !

I agree with Peter.
A lamp kit is available and it comes with detailed (dis-)/assembly instructions but the lamps are soldered
in boards which means that basic soldering- and electronic skills and tools are required.
If you don't feel up to the job yourself, grab a lamp kit and bring it with the Beomaster to your local repairer.
If a few lamps are out, the rest will be marginal too and their filaments will be brittle. The unavoidable
vibrations from servicing and handling of the boards will break more filaments so I suggest replacing them
all in one go. That will give a fresh life-span to them all and also provide an equal light output.

Martin

Thanks guys! I was hoping it would be something as simple as the bulb.

I don't have much experience taking apart electronic units like this, but I am pretty handy with a soldering iron, so I think I'd give it a whirl. Where can I find these lighting kits? Approx how much should I expect to pay? Are there any online guides that I can follow before buying (maybe a wire just needs to be re-soldered, for example).

Thanks again! :)

You have a PM, check your inbox at the extreme top right corner of this page.

Martin

The lampsbulbs used are 12V/30mA diameter 5mm / lenght 11mm. There are 15 of them.

I couldn't find the right dimensions, but I used these one " http://shop.conrad.nl/elektronica-meetapparatuur/componenten/elektromechanische-componenten/gloeilampen-met-soldeeraansluiting/720118.html "  instead and it works beautifuly (the metal clips are not tight anymore, so make sure they won't be able to get in contact with the lamps wires ;) ).

Soldering the is not a big issue. This was my first soldering project and I was done in 2 hours (excl putting together the machine again, that took me 2 hours as well ;) ).

Just PM me for questions if you want to know more.

I did my BM2400 lamps with a kit from Dillen and they are all working fine now. The kit contains exactly the right size lamps so that the clips still function correctly, and this too was my first proper soldering project and I found the instructions supplied invaluable in helping me along the way :)

Unfortunately, 12V 30mA is stated in error in some early service manuals but does not correspond to what's factory mounted in
the Beomasters.
They will not give correct function to the tuning discriminator lights, typically leaving the two just lit up showing nothing at
all and, since they don't provide the correct load on the 15V supply, they will in many cases cause the Beomaster to turn off
by itself intermittently and/or make it hard or completely unwilling to go into standby or change to specific sources, depending
on the general state of the rest of the Beomaster.
B&O issued a tech note about this.

They will also give different light output since some of the Beomasters lamp circuits are balanced and current controlled where
others are just supplied from a plain analogue source so it won't look as the designers intended.

I've had Beomasters sent to me for service where the only faults was that wrong wattage lamps or lamps of different wattage
were mounted.
The lamps mormel link to are cheap china types, not high quality long-life types and they will
require replacing quite often.
Some of the lamps in this series of Beomasters are living a fairly hard life and if the load on the supply is
too light, which it will be if mounting lamps with too low wattage, the voltage will be too high and lamp life
will be short.
Plus they won't fit into the lamp holders, which again will allow them to vibrate ever so slightly and their filaments will
become brittle in no time.
People, who owned Beomasters through the 1970's and 80's, will remember that lamps were an everlasting head-ache,
and that was because the owners bought the cheap lamps supplied by radioparts dealers instead of spending a little more
and buy the correct and better ones from a B&O dealer.

I recommend you use long-life types only and of the correct wattage. Preferably types capable of handling a continous 15V DC, since
many B&O lamps are slightly overrun and will stay lit for hours. The three balance/treble/bass lamps are always fully lit when the
Beomaster is powered on and they form part of the electronic switch circuit, decharging the 15V secondary at switching off.
Correct lamps can be hard to find and the typical cost is about EUR 3/each (a little cheaper if you buy 10.000 pcs.) but
are, as J0hnbarker also suggests, available as a kit which also comes with instructions.

Martin

You're probably right of course, but as I said, I have no strange behavour (even the tuning indicator is working fine) of the machine and the light intensity is simular to what I remembered as it should be. I don't use the 2400 on a daily bases, so I just needed a cheap quick fix and it just did the trick for me anyway, maybe I'm just lucky.. We'll see how long it will last :).

Well, the only references I have are the service manuals plus correction sheets and
updates, 35 years of experience in collecting and servicing B&O audio stuff and
the tech info sheets released from B&O to their authorized repairshops.
Not much, I must admit.  😂

You are happy, that's the most important thing.  🤒

Martin