weaker (no bass) sound in right channel Beomaster 1900

Hi All

Just revived my Beomaster 1900 with a lamp kit and potentiometer fix from Dillen

I can really recommend these kits and the excellent instructions that made the disassembly / assembly a walk in the park!

The replacement sliders just needed a little cleanup regarding flash from the injection moulding then they worked just fine.

I noticed one funny thing regarding the pots, my balance slider was of a different type than the others and used a thinner round shaft for the slider instead of the rectangular. The balance slider was however still working so i just cleaned it and borrowed some grease from the others for the shaft. I also replaced the rectifier per Martins instructions. What type of grease is this in the potentiometers? I've seen some special fadergrease mentioned but it is quite hard to come by.

When i fired up the receiver after the surgery everything worked as intended but i noted that the right channel seems a bit muffled, i haven't replaced any capacitors so i guess that's what comes next. 

Can bad electrolytics be the cause of the muffled sound?

Guess Martin will get an order for a cap kit soon

Cheers

//H

Here is a picture of my balance slider.

As seen it is of another type compared to the bass and treble ones.

This one was functioning correctly when i repaired the other two, could this be an earlier replacement?

 

Henrik Johansson:

Here is a picture of my balance slider.

As seen it is of another type compared to the bass and treble ones.

This one was functioning correctly when i repaired the other two, could this be an earlier replacement?

 

Yes, and it will be fine as-is.

Martin

Henrik Johansson:

When i fired up the receiver after the surgery everything worked as intended but i noted that the right channel seems a bit muffled, i haven't replaced any capacitors so i guess that's what comes next. 

First of all I would try to switch the speakers to see if it is a problem of the amp or maybe the problem is the speaker and you have to recap the crossovers in them...

Regards

Tried switching between the speakers yesterday and tried the b outputs aswell.

The problem moved when I switched l/r speakers so I guess the problem is within the amp and not the speakers.

Then I started flipping the switch for volume preset and voila' all of a sudden a slight plop! And both channels sounds equally good again.

Clearly something is still not ok but now the unit sounds like before the lamp and pot fix.

Ordered a full cap kit that I will install when I got the time for it.

But at the moment I'm enjoying a fully lit and great sounding B&O again!

Check the wires going to the connectors below the tonecontrol board.
They can sometimes short to nearby solder joints on the PCB.

Martin