John Bowers Active One
Forum Audio : High-End Audio - John Bowers Active One
Hello Mr. Asherson,
Congratulations to your speaker and that you kept it for such a long time, I'm sure you know why, Active ones are excellent Speakers.
Sometimes the electrolytic capacitors or final stage transistors blew up. I was talking to many guys about this, even with a important service master at B&W (I don't remember his Position). He knew the problems and told me there is no way to solve this and the speakers are lost forever. BUT I did not give up and was just asking an older and experienced electronic technician specialized in TV and Radio and he told me that it is NOT possible that it is impossible to repair a final stage! This was 4 weeks ago and till now one of two broken active 1 runs fine again 
, the second one still needs some parts which are in delivery. He has to do some modifications to the board to fit the new parts but then both will run as on their first day, he promised me.
So the only advice is go and find a good electronic technician and tell him, you have something really special and if he is honourable he won't miss this chance if he knows what he does, it's an easy job for him. Don't trust lazy guys which tell you that it's not worth and impossible to find parts. Of course it is not possible to find original parts, but when they use their brain and their profession they will find the way... But be aware, beside the hourly wage, the transistors are expensive, a repair will be something between 100USD - and 350USD!
Good Luck and let us know what happened to your old beauties. Don't give them up! If you will, please contact me on this thread...
Best Regards
Martin
Germany
I don't know the details, the only thing I'm left with, is the "Circuit Diagram - Power Amplifier P.C.Board - Mid and Low Freq"
He marked the R339 with "not applicable" and the R340 "smaller Value 2541058 0 <----> S " he noted this for the case, he ever has to repair them again and he was sure he will forget these facts, but he did a lot of more stuff which I got sadly no clue about. He admitted that he had to dig out some literature from his college times, because it was so complicated and unusual. Be aware: in the Circuit Diagram is a misprint, which caused the first new set of Fets to blow up 
so be careful when switching them on for the first time, it's better to check everything careful before. But sorry, I got no further details about this too 
. The only thing I know, is that I'm still in love with these rare gems.
Best Luck,
Martin
