Vintage Products

Re: Beomaster 2400 volume problem

BenSA — Thu, 14 Jan 2010 13:21:16 GMT

Thanks Martin for that description and for the photo. Was really interesting. I can't believe I have never noticed the LDR's before!

Re: Beomaster 2400 volume problem

Dillen — Thu, 14 Jan 2010 09:57:49 GMT

Dave,

If it fails, you will have lost a wonderful 1970's design icon and a nice radio but you won't fail.
You have a PM (check your inbox at the extreme top right corner of this page).

Martin

Re: Beomaster 2400 volume problem

swissmart — Thu, 14 Jan 2010 09:39:38 GMT

Firstly,thanks for the prompt replies Guys.

I'm in Switzerland and my experience of labour costs here rule out a dealer as a viable option.

I'm no B+O repairer but as i said the self repair would be my pleasure.As i see it i have a unit not working,it's cost nothing and if i fail what have i lost?

I would be greatful if you can give me details of:LDR(used replacement),Capacitor Kit.Also information if any supplied with components

Dave

Re: Beomaster 2400 volume problem

Dillen — Thu, 14 Jan 2010 07:27:33 GMT

LDR stands for Light Dependent Resistor. It's resistance varies according to the light that shines on it.
Inside the Beomaster 1900/2400, a tiny closed casing contains a lamp surrounded by four LDR's.
The volume control circuit changes the light output from the lamp which in turn changes the resistance
of the LDR's.
Two of the LDR's are sitting directly in the signal path handling the volume, the other two handles loudness/filters.
The circuit has been made so that the more light, the lower volume.
This again means that if the lamp burns, the volume would be brought to max.
- If it hadn't been for a little clever circuit that constantly monitors the lamp current and if it falls
below a specific level, the circuit issues a mute command.
If the lamp burns the Beomaster will be silent (or nearly silent).

Different LDR's:

The two red volume indicator lamps on the front panel does not control anything, they just indicate.
Remember that electronically controlled volume controls (without a motor, gearbox and a potentiometer)
was breaking news and also one of the things that made the Beomaster 1900/2400 so technically advanced
for their time and also helped to path the way for a remote control.

Martin

Re: Beomaster 2400 volume problem

BenSA — Thu, 14 Jan 2010 06:33:14 GMT

Sorry Martin, what does LDR stand for and what do they look like?

Re: Beomaster 2400 volume problem

Dillen — Thu, 14 Jan 2010 03:26:27 GMT

Welcome to Beoworld !

I agree, capacitors can never be ruled out but there is also the LDR casing, that is the actual volume controlling device.
Inside the LDR casing are 4 LDR's and a lamp. If the lamp burns, the Beomaster will mute.
If the fault is indeed this, I can probably help you to a good used replacement device (or your own can be repaired) but if you are not
an experienced B&O repairer I suggest you bring it in for a pro service. It's not the easiest thing to service, especially putting it back together.
There can be other reasons for the fault but grab a capacitor kit and send with the Beomaster and don't let the repairer tell
you that they cannot get correct parts for the repair.
A lamp kit is also available containing a full set of fresh bulbs for the front panel.

Martin

Re: Beomaster 2400 volume problem

BenSA — Wed, 13 Jan 2010 13:10:03 GMT

Sounds like the usual capacitor problems. You need to replace all capacitors as they leak or dry out with age. They are usually dark red or orange. There's quite a lot of them, you can get a capacitor kit from Dillen on the forum.

Beomaster 2400 volume problem

swissmart — Wed, 13 Jan 2010 09:44:14 GMT

Hi All

i am a first timer'so here goes.

Have come across a bm2400(in-laws)which has not worked for 10 years or so.

It powers up and all the lights work.The volume is audible but just a whisper.Volume up or down makes no difference even though the indicator lamps transfer the volume correctly.i get no hum from speakers.Stereo lamp indicates as it should on stations.Same symptons when connected to a known good B+O tape deck.

The balance indicator lamp on one occasion did'nt work(although on 100 other times it has).Tried swopping speaker outlets etc.Have also tried it on220v aswell as 240v.i would love to get it working by fixing it myself,so i hope i can get some help with it.

Thanks

Dave