I have a Beomaster 6000 with a couple of faults, one being a faulty volume control. It started off becoming sticky then over time has got to the stage where it has failed completely. 

Tension on the string is fine, and now to adjust volume I have to lift the lid and manually move the string to change the volume which is annoying!

It doesn't work using the remote either!

I have the service manual, and another Beomaster 6000 for parts - I just wondered where the best place to start fault finding would be?

I swapped out the motor control board (board #6) just to try a quick fix but this didn't cure the problem!

The other fault is that the amplifer cuts out and goes into stand by when the volume exceeds around 35-40 on the scale. If anyone has any idea what could be causing this or where I should start looking that would be great!

Any ideas or advice appreciated!

Have you tried a new belt on the servo? There is quite a bit of torque to overcome on the volume control with this set and a slightly aging belt will fail to move the volume past around the point that you mention. Also I have tried various belts with little long term success, but just received Martins which are to original spec - Not had time to fit yet!

Regards cutting out have you checked quiescent current and offset as per the service manual? That would be a good start I think it is within the first couple pages if I remember about 22mV and <5mV across the respective test points.

Hi Olly

Cheers for the advice! I have no tools or test equipment (or space) so it's a bit of a struggle for me to attempt repair unfortunately :(

The motor doesn't drive - I should imagine if I tested for good voltage at the motor I wouldn't be in luck! The mechanicals, I'm sure, are all OK - The string belt has good tension etc.

I don't think the fault is with the button board or microprocessor either as everything else functions fine. I would like to swap out the motor board but it's too much of a job for me to take on (as you have to remove the board it sits on), with limited tools and nowhere to work!

I had this problem on one a couple of years ago. I did the required recap, new pots and current adjustments. The problem was still there.

Turned out that the parallel resistors in the output stage and a zener were shot.

That fixed it.

Not recommended for repair by a novice.

Menahem

In this case Yachadm the bipolar (part of the fault detector) in the left channel was the culprit. replaced and it is just fine :) Currently listening to radio 2 with it right now :)

Right - so it goes back to our standard BeoWorld mantra to always start with a cap kit ;-)

Actually I only ever go for the recap if I know the unit is fully operational. I think this should always be the case personally but I prefer the challange of actually locating the fault(s)...

The unit I lean't to Llewelyn still has the original bipolars in despite replacing all other electros in the amp section - I will now correct that when I get it back!