ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hello all,
i have bought a beomaster 901 in second hand shop.
When i first pluged it there was no lights on it, then i open it and i notice that one of the fuses was broken.
I have replace it, then the lights they came... then i connect the speackers and no sound out.
So i notice there is no connection inside that came from the speackers.
Anyone has some images of the inside connections of the speacks tha could share.
Sorry about my english.
Thanks in advanced.
Renato (Portugal)
Welcome to the forum, there are service manuals available for silver and gold members on the site, from the schematics you should be able to repair the missing connections
Collecting Vintage B&O is not a hobby, its a lifestyle.
Thank you very much.
I already have the scematics but i couldnt understand where are the speackers and how they are connected... after all i dont want to try a wrong connection with a bad interpretation of the diagram.Thats why asked for some images.
I think I have a BM 901 open somewhere, will look for it later today, and see if I can get a pic of the connections
That will be great !!!
Thanks!
Apparently there are 3 different types of the 901, one with 2 speaker jacks, one with 2 speaker jacks and headphone jack, one with 4 speaker jacks and headphone jack. Mine is 4 speaker and headphone. I strongly suggest you make the connections according to schematics, if you cant read or understand the schematics please look for a technician that can.
The connections comes from here
And goes here
Thank you so much for the images.
Mine its two speackers and headphone.
I can see the board is a bit different, maybe i can connet the speackers in the same output of the headphone (??)... i have tryd the headphone and theres lots o hum and distortion.
I gonna study better and see what happen.
Thanks again!
The speakers positive wires goes through the headphone switch, and then to the speaker jacks if you have hum in the head phones there may be more failures like electrolytic capacitors
Thanks Soren again.
Thats what i thought to... capacitores or in worst case transistors... because one 39k resistor burned... i have replace a new one with the same specs and it burns again.
The positive wires goes throught the headphone and the negative wires where are they connected?
Thanks
Negative is connected to the flat pin of the jack and to ground ("0"), if one of your 0.39 Ohm resistors keeps burning check your output transistors and all the diodes 2D19 to 2D26 if the output Transistors are bad, change all of them 2D21/22/30/31. and then all the small transistors in the output stage (B&O recommended that), Check your bridge rectifier
I left my 901 with a technic.
Hope it will comes alive again... i let you know.