Beomaster 4000 fixing help + ideas please!

[profqwerty]

Hi everyone, I'm new here, and really sorry for my first post begging for help but I'm sure I'll be back here filling you in with this amp's life story. I figured it's probably about the same as DIY so this forum would be suitable too.

I've dug up my mum's Beomaster 4000 from the grandparents attic, with Celestion Ditton 33 speakers, and a B&O turntable. I've left the turntable up there as not needed at the moment.

So I've got it all set up, beautiful system, really psyched about using it in the future The only problem being someone's cut the power chord too short so it looks a bit Opening it up the cable's been resined in, can't change it (for now anyway).

But anyway, the main problem is it's a bit crackly. This happens when moving any of the sliders, and clicking one of the switches (eg filters, mono, loudness, etc) makes it crackle for a bit. When turning on it makes a nice loud thud then crackles and "whooshes" and dies down to fairly silent. In fact pretty much any movement of anything, or just leaving it with no music playing results in a bit of crackling and whooshing. I opened it up and one of the power supply caps has leaked, so will replace it. It neatly comes with a schematic which's being helpful.

Also, the left channel tends to go very quiet, then pressing the mono button and few times and generally moving sliders generally brings it back to life.

Does anyone have ideas what I could do to try and resurrect it? I understand capacitors would probably have dried out so I'll replace as many as I can. New ones don't seem to fit the holes very well! What's important to try and match for capacitors? Just the capacitance, or what about the operating voltage?

On a side note, one of the tweeters has blown (I tested parts between the pair) so got another one on order.

Many thanks!
Toby

[sjdemark]

The first thing I would try is to spray Deoxit in all of the volume / tone controls and in all of the switches. I think that will go a long way to fixing the crackling and drop out sounds. It also sounds like it is due for a recap job.

When replacing the caps, the uf rating must match and the voltage rating should be no lower (but can be higher) than the original caps. Other than that, you can get very sophisticated with your capacitor brand/line selection in an attempt to improve the sound quality, but to keep it simple in this case, I suggest just buy the size that fits and buy a name brand. Also, make sure you put them in correctly, with the striped side usually on the negative side. The easiest thing to do there is just make sure you note the orientation of the original as you pull it out and put the new one in the same way.

[profqwerty]

Awesome thanks. Got some Deoxit ordered! Then shall see how that turns out.

I think I'll be going down the simple route yep! Many thanks for the info, will post how it gets on!

[ingenieus]

Now this takes me back. The parents of a good friend owned a Beomaster. I can't remember which exactly model it was. It looked the same, but had fewer inputs and it was therefore lower down in the order from the 4000. It was was matched with a B&O turntable and speakers and many an hour of my youth was spent listening to music on the system. This one is a keeper. I hope you get it sorted.