Hey there Everyone. I have a buzzing and very quiet left channel on my Beomasterr 2200, i have dismantled and found that the tension mechnism within the balance control slider has partially collapsed. I will attempt to fix it, but it looks like a new slider may be the proper route. I have contacted B&O direct and they said as the part was for a vintage machine, Beoworld would be the best place to start tracking one down. Does anyone have the contact details for an outlet which could help me? or does anyone have the part itself?! I suspect it is a part common to many of the tuner/amplifier/beocorders and beograms of the period, it was manufactured in 1978-79.

All help Much Appreciated!

Jonah.

First a warm welcome to Beoworld !

Next, congratulations on owning one of the most overseen, simple, yet superbly built and sounding, receivers and amplifiers ever built by B&O.

The tonecontrol sliders are of the same type as the ones used in the Beomaster 1900/2400 series but they also fail here. B&O knew about this problem and at some point new sliders were available as a kit but no longer I'm afraid.

In most cases, the sliders can be taken apart, parts cleaned and the bronze parts super-glued back onto the sliding plastic bridges and repaired this way. I've done hundreds. Of course this can only take place if all parts are still present. Watch out for the little coal-tips, held in place only by the spring tension of the bronze sliders (and old habbit). We've had this problem discussed here before, I'm sure a search will show more results, probably best luck if searching for the 1900/2400.

I am not sure, I have any complete sliders in stock at present but I may be able to help you to discrete parts if that will be of any help to you.

Martin

HI Martin, Thanks for your advice. I have repaired the slider, but the problem which i thought it was causing still persists. there is a low hum in the laft bchannel, i thought it was due to a problem with the ballance control, bad contact, poo earth, but apparently not. The noise gets loader as i put a finger near the small blue capacitor at the top of the balance control, there are no outward signs of this component being damaged.

the insignia on the side of the capacitor (if that is indeed what it is) is unclear, it says 63V phillips 015FA 4u7 T

I am familia with capacitor nomenclature and this is not something i recognise, the 63V is clear enough, but the 015FA is unusual, as it is clearly much too small for a 15 Farrad capacitor. Do you think it could mean 0.15F ? And the 4u7 T is also bizzarre the u may refer to  micro which is the units in which capacitance is usually given, (uF) but it is separate from the FA.

i'm not even sure if it's whats causing the problem or this proximity related buzz volume increase is just a symptom of something else.

I'm a little baffled. And i miss my sound system.

All help appreciated music lovers.

4u7 is the Philips way of writing 4,7uF but it's quite normal to see a "finger-antenna" introduce hum into the signal way so I wouldn't judge this particular capacitor.

Generally, in this model, humming is caused by leaking and/or dried-out electrolytic capacitors, especially in the power supply and related circuits on the amp sections etc. Humming can also be caused by a too high load on the power supply from f.e. badly set idle currents but this usually also shows as heat build-up on the cooling fins, even after only a minute or so and with volume at zero.

I haven't seen a BM2200 that didn't need a fresh set of caps for a long time and I would recommend you grab a kit and replace the lot before diagnosing any further. It may save you both time and money in the long run.

Martin

Have just dismantled the beast completely, there is no outward sign or damage to any of the capacitors, but the finger antenea effects seem to be centred around the affore mentioned capacitor just above the ballance slider. Notably the higher frequencies of the hum dissapear when i touch the silver box into which the FM arial goes, with lots of adjustment screws in the top of it. there is still a hum though, i have tried tweaking the screws, to no avail, (i took a note of their origionla position, and returned them to it), there is no heat build up in the fins either. I suppose one of the Capacitors may have failed internaly. What do you guys think?

Cheers, jonah.

Martin can usually supply a capacitor kit - well worth it as they can cause all sorts of odd effects!
 

Most electrolytic capacitors in pre 1990 electronic equipment have reached their design life and are or will soon effect the operation of the equipment.  The electrolytes (chemicals inside the capacitor) evaporate over time depending on temperature.  This is why you should really change all of them on old B&O equipment.  It really isn't worth taking a delicate bit of equipment to bits to change one component.

See http://en.wikipedia.org/wiki/Electrolytic_capacitor#Electrical_behavior_of_electrolytics for more details if you are interested.

Richard