Ok, I started looking around in the volume control section and found a component that seemed to be cracked on the top, in the same way as the old capacitors.

It is named TR9. What is it and could it be the culprit?

I will try to get a picture of it.

Here is the pictue.

The TR9 is about in the middle, a similar TR? can be seen a little to the left. Login to view image

TR = transistor, C = capacitor, R = resistor, D = diode

Under the green wire below TR4 there are 2 resistors where the leads are touching each other = shortcut, if the TR9 is blown you may have more failed components in that circuit, check the other TRs and the diodes around there

Thanks for your reply  Søren ,

I replaced the component, transistor as I know now, but the problem is still there.

I bent the two leads apart; thanks I hadn´t seen that. Unfortunately I have tried the BM before I saw your reply, so I might have blown the replacement as well. It still looks good though.

I do see that TR4 also has a cracked top, so I will have to buy a bunch of them.  I will contact Dillen about that.

Your help is much appreciated.

Hans.

Hans you are working blind, if a component like a transistor blows it is because of another failure like the shorted resistors, if one transistor in a circuit blows like the TR9 and now TR4 there is a failure in another component, just blindly changing components one by one will not solve the problem, if you cant read a diagram or dont have a diagram I cant help you, You must check diodes on that PCB with a diode tester the Resistors with an Ohm meter and transistors likewise, to check the transistors you will have to desolder them and check them one by one. At least you will need a digital multi meter to  check it all.

As you are in Sweden there are beoworlders maybe near you that can help, Halmstad, Ørebro, Stockholm comes to mind, there is also a Swedish group on FB

All right Sören, I will start a more structured search for the problem. As you already guessed I am a novice with electronics, but I have a good multimeter en I will search local help about the use of it for these electronic componenets.

I live in a small village, Örebro is the nearest town you mentioned, but still a good 100 km away, so I will first try help locally.

But it is clear to me now that I will need some instructions in the finer use of the multimeter.

I do have the diagrams for the2400.

Again, your help is much appreciated and I will post any progress.

Is the volume high from the moment you turn on the Beomaster or does it start at a low setting and climb up as if the
volume up pad was touched?

Martin

Hello Martin,

The volume starts at a normal level, I can still de- and increase the volume. But after maybe 15 seconds it increases out of its own and from that moment on I cannot decrease the volume anymore.

The volume+ lamp on the board does not become brighter with volume increase.

Hans.

Update:

I checked all the 42 resistors and three of them were out of range: 1- R22 should be 100K, was 6K

                                                                                                                         2-R33 should be15K,  was 11K

                                                                                                                          3-R34 should be 39K,was 12K

And I think that all my trouble is my own fault, because I shortened these resistors.

So far it is clear, but I also measured the transistor I took out of the board (TR9) , it read BC557B on the top and gave 148 hFE.

So it seems to be still ok, or not?

Then I checked the transistor list in the service manual, page 19, and it gave a model number BC548B.

The transistor I took out of the board is a PNP,  the model in the transistor list is a NPN.

Could the manual be wrong about this?

Hans.