Monitor Audio Subwoofer BXW-10 Fuse Blowing

begbie1976

Novice Member
Hi everyone. I've had a dig around for an answer to my problem without success, so apologies if I'm asking an old question. Hope you can help.

After some decorating, I set up all my equipment again, thinking all was well, until I noticed that there didn't seem to be any life from the sub. Checking the rear of the sub, no green light on. First stop was to change the fuse on the plug - nothing. Next move was to replace the fuse within the sub - success, the green light came on....then a pop as the fuse blew again. I'm waiting on more fuses being delivered, but instructions on the manual state that I should seek help from an authorised service agent and not to attempt to fit another fuse as it could result in serious damage.

I may also have used a power cable from an old TV, a 3-pin - could that cause this? The socket on the sub only has 2-pins. I'm a mechanical engineer, not electrical, so sorry for daft questions! If anyone has a photo of the BXW-10 power cable, that would confirm whether I have the wrong one. I've thrown the old TV out, along with the power cable, so can't check what I had. :facepalm:

Am I looking at a potential expensive fix - maybe a fault within the sub's psu? Any help would be much appreciated - I'm missing the rumble!! 😁

Thanks in advance.
 

dobrykamil

Well-known Member
BXW-10 has two power supplies, standby and main for the amp.Since you got green light before fuse was blown, I reckon main psu require repair. It's switched mode psu type, so I belive two switching transistors are blown, and possibly other surrounding them components. It's fixable, and someone right skills should be able to bring it back to life.Here is a forum thread of the bloke, who I managed to fix his sub.
 

begbie1976

Novice Member
Thanks for the reply dobrykamil. Unfortunately it's all Greek to me. One of my neighbours is a retired electrician, so I might try him first, and give him with the info you've provided - thanks. Failing that, I may be back online seeking further help.

Reading more on this, I think the problem may have been caused with the sub being constantly switched on. I wasn't very regimented in switching it off. Once fixed I'll used the 'auto' function or just try to remember to switch it off.

Thanks again.
 

begbie1976

Novice Member
OK, my neighbour is an HV electrician, no real experience in electronics and wouldn't want to even touch the subwoofer for fear of blowing it up more than it might already be. Also, the fuses arrived today. I blew 2 more while trying out a different lead and a different set up on the sub. In both cases, the LED came on and within a second, the fuse blew again.

So, I'm now at the mercy of you guys. Can someone point me in the right direction of where to start, or should I just find a local AV specialist? My neighbour said that he'll lend me his meter and soldering iron if I need them.
 

dobrykamil

Well-known Member
Disconnect those two cables and let me know, if fuse was also blown after.
223C1E1E-1234-46FD-AD1D-896D78B750E1.jpg
 

begbie1976

Novice Member
To remove the backplate, am I just removing the perimeter screws? I've done that but it won't budge and I don't want to unscrew anything else. Do I just need to prise it open?
 

begbie1976

Novice Member
I can't see anything resembling your photo on my circuit board.
 

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dobrykamil

Well-known Member
Aye, because that’s BRW10 amp not BXW10 😉
 

dobrykamil

Well-known Member
I’ve fixed 3 or 4 of those amps before, I can tell you that too many things could have gone wrong, starting with that wee pcb board covered with that black sh*te, which causes corrosion and dry joints. This is a job for someone who knows what is he doing.
 

begbie1976

Novice Member
I’ve fixed 3 or 4 of those amps before, I can tell you that too many things could have gone wrong, starting with that wee pcb board covered with that black sh*te, which causes corrosion and dry joints. This is a job for someone who knows what is he doing.
Sounds like you know what you're doing! Is the black sh*te there to supposedly protect the components then, and it's not a fried board?

Would you be interested in fixing it?
 

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