Just purchased a BM4000. One problem it has is that the Tuning String is broken. Are these easy to replace? Also, is it a special type of string?

Craig 

Normal dial string is what you need. Nothing fancy here.

Restringing can always put your temper and patience to the test

you will need lots of time and strong coffee, but the Beomaster 4000 is not the worst one to deal with. It doesn't have a lot of bells and whistles but merely the potentiometer wheel, a little wheel each end plus the knob. A spring keeps the whole thing tight. You only need to make sure that the slider moves the right way compared to the tuning. I am almost sure that the service manual gives some info but I can also mail you a couple of photos if you need. 

Unsolder a couple of wires to the potentiometer, losen 2 screws and you can take the whole bracket with all wheels out of the Beomaster, restring it and put it back in. Only thing left is to fix (I often also glue) the slider to the string.

Use the remains of the old string for length reference if you can.

Martin

I use braid line for fishing the carp (Derbygreen Tortue 27.18Kg / 60Lbs)!

It is braided with green and white wires and looks exactly like the original

B&O tuning string.

It is so strong than it will never break again!

Marc

I have some proper tuning drive cord Craig. Drop me your address on a PM and I'll send you some.

Chris.

Thanks Chris, PM sent.

Craig 

Well sat down last Night to replace the Tuning String. Took bthe top cover off and found the String has not snapped. What has happened is the small plastic lug which the Spring locates on has snapped off. Looks like I need a replacement plastic disc.

Craig

It can be superglued back in place. but you'll need patience.

If you can obtain another then that is better.

Thanks Dave for the reply. Take it then it is a plastic that will stick with Superglue. Plastics can be a bit hit and miss when it comes to Superglue.

Craig

I haven't eyeballed the insides of a BM4000 but it sounds like what has broken is something like this?

i.e. a wheel, into which a the string is pulled by a spring that wraps around the hub and hooks onto a lug? The idea of this thing is to keep the string tensioned even if it stretches a bit. If this is what we're looking at then I've successfully mended  the equivalent in a BM2000.

What I found was that superglue simply wasn't strong enough to withstand the pull of the spring - if you succeed then great, otherwise I suggest you do what I did. With the lug completely broken off I measured the thickness of the base and cut a round nail down to the combined length of that plus the length of the lug itself. What I got was something that looked rather like a miniature top hat, only solid. I drilled out the base of the wheel where the lug had been, and pushed the modified nail though to check the fit of the new lug and clearance for the nail head - I needed to file the head of the nail a bit to get it snug. The nail came out, was treated to a dab of glue to hold it in place (I used JB Weld) and pushed back into the hole. Turning the wheel over, I was looking at a new lug made of steel, exact same size and position as the old plastic one. After that it was simply a case of letting the glue set and reassembling - the steel lug is much stronger than the original and I don't expect it to break again.

Cheers,

Steve 

My bet is that the some (or maybe all) of the three little pins protruding at the backside of the slider has broken off. The string is zig-zag'ed between them and it's very common to see one or more broken pins. (Photo shows a slider with two pins still intact).

One pin is enough if you glue the string to it. Of course, you should make sure to have the dial and tuning matched before glueing.

Steve, you did a good job and I'm sure it won't break again. Repairing using most of what is left is very rewarding but you could also have asked me for a part...

Martin