Subwoofer repair

[dasjambo]

Hi all, a couple of weeks ago my subwoofer stopped working. I found the best place I could find locally to bring the subwoofer in for repair, and the technician told me the mainboard was shorted and needed to be replaced, but that none of the vendors he contacted had the replacement part. He was honest that he didn't spend that long looking, though, and sent me a couple of pictures in case I wanted to keep on trying to do research to find the replacement part (photos below, 011-321000-00). He also thought it might be possible to replace the board with another make, but he wasn't sure how to find out what would work.

The manufacturer, Blue Sky, is no longer around, and I'm super out of my league here -- anyone have thoughts on next steps I might take? Would be a shame to have to throw out an otherwise functional subwoofer!

So grateful for any thoughts folks are able to share. Thank you!

Photos here, if that helps...

Thanks again!
-James

 

[danadak]

1) Any signs of heat, post a pic of bottom side of board.

2) Any bulging or leaky caps ?





3) Any burnt resistors ?





Google "poor solder joints" and look at images found so you can inspect bottom of board
for cracked joints and high current melting......


Regards, Dana.

 

[Martaine2005]

Hi James, not a very good technician!.
Do you have a multimeter and soldering iron?

Martin

 

[dasjambo]

Thanks very much for these thoughts, Dana and Martin! Maybe I should have said I don’t have a soldering iron or any technical skills at all, and the subwoofer’s still at the shop so I can’t post any further pictures. I guess what I was mostly hoping for was a sense of whether this is a lost cause, or whether it could still be repairable by a more skilled technician that I can do some research on, but would be about a two hour drive away. And/or if anyone has ideas on how to find a replacement part so the technician who has it now can just swap the board out. From your posts, it sounds like it would be worth making the drive to another technician that I trust more, like there's hope the board could be repaired? Thanks again!

 

[kellys_eye]

The technicians response is likely based on the (appropriate) cost-benefit analysis. With an unlimited budget (yours!) I'm sure he'd be willing to do what is necessary but are YOU willing to pick up that bill?

This is where a DIY approach is the only reasonable solution. Get it back and post pics and get a test meter to take some readings that we can use to identify the fault. Then purchase the parts and tools required to replace dud parts. See where this is going?

 

[dasjambo]

Honestly it didn't even occur to me that this would be something I could DIY given that the Y is me and I haven't done this before...but I guess there's a first time for everything and I appreciate the encouragement and the offer to help me through the process! Sounds like a fun project. I’ll come back when I’ve picked it up and am ready to get started

 

[Bluejets]

As above, my thoughts were that cost would have been in the mind of your techie......
Sometimes, as I once found with a Panasonic unit, even DIY with considerable knowledge is a waste of time.
Much easier, quicker, cheaper to source a second hand working unit online.

 

[crutschow]

How much did the subwoofer cost and what is the rated power of the amp?

Depending upon your budget, you might replace the amp with a subwoofer plate amplifier, such as one of these.

 

[dasjambo]

How much did the subwoofer cost and what is the rated power of the amp?

Depending upon your budget, you might replace the amp with a subwoofer plate amplifier, such as one of these.

It was a few hundred bucks a while back. I don't like throwing things out though! And it's part of a set with two studio monitors that feed through it, so I don't think these plate amplifiers will work, but otherwise that would have been a great thought!

 

[crutschow]

The feed through for the monitors is to generate the low frequency rolloff to be compatible with the subwoofer response, but you may not need that, depending on what you are using to drive the monitors.
Standard surround-sound receivers with a sub output usually have that rolloff built in.

 

[crutschow]

Scratch my previous post,
Apparently those monitor speakers are self-powered.

But is does look like Blue Sky is still in business.
Is that not true?

 

[crutschow]

What is the music signal source for the speakers?

 

[73's de Edd]

Sir dasjambo . . . . .


Direct your visual attention to the photo aspects of the amps heat sinked power output section on the board photo.

Now . . . . MOSPEC . . . . . . branding mark sounds like an exxxxxxotic power transistor.
BUT, in this / your case, its being a common TEXAS INSTRUMENTATIONS *** derivedTIP31 silicon power transistor which has been around since the late '60's.

*** ( DYK ? . . . Back in pre production, engineering days this was a cheaper epoxy packed, heat sink tabbed, more economical replacement for the then much pricier metal cased TO-3 package, and was dubbed by the prefix of Texas Instruments Product + respective numbering suffix. . . . . 31 on this unit )

Now ZEEEEEEEERO your tri focals in on board center and seek out R-uh 60 reee-sistor . . . as being a green-blue . . . .brown or red ? 560 or 5600 ohm resistor . . . . but MOST importantly . . . . . . now at its top left side do I see the limited right half view of a heat charred R?7 resistor ? Hmmmmmmmm ? Hmmmmmmmm ? Hmmmmmmmm ?

Looking forward to your getting the unit back home for a more in depth analysis.

73's de Edd . . . . . .


You know that metal plate that I have in my head?
Well . . . . . I HAD ! . . . . to have it replaced with a Teflon one, 'cause every time my wife revved up the microwave
. . . . . I’d immediately piss and crap my pants simultaneously and TOTALLY ! forget who and where I was for about a half an hour or so.

 

[crutschow]

You know that metal plate that I have in my head?
Well . . . . . I HAD ! . . . . to have it replaced with a Teflon one, 'cause every time my wife revved up the microwave
. . . . . I’d immediately piss and crap my pants simultaneously and TOTALLY ! forget who and where I was for about a half an hour or so.

Why does that not surprise me?

 

[73's de Edd]

Why does that not surprise me?

No . . .Sir crutschow
What superficials you are seeing / reading . . . in my posts is the lateral side effects of trying to read, follow and "apprehend" roughshawd's posts.

 

[applianceschoices]

Hi all, a couple of weeks ago my subwoofer stopped working. I found the best place I could find locally to bring the subwoofer in for repair, and the technician told me the mainboard was shorted and needed to be replaced, but that none of the vendors he contacted had the replacement part. He was honest that he didn't spend that long looking, though, and sent me a couple of pictures in case I wanted to keep on trying to do research to find the replacement part (photos below, 011-321000-00). He also thought it might be possible to replace the board with another make, but he wasn't sure how to find out what would work.

The manufacturer, Blue Sky, is no longer around, and I'm super out of my league here -- anyone have thoughts on next steps I might take? Would be a shame to have to throw out an otherwise functional subwoofer!

So grateful for any thoughts folks are able to share. Thank you!

Photos here, if that helps...
View attachment 56363View attachment 56364
Thanks again!
-James

The technicians response is likely based on the (appropriate) cost-benefit analysis. With an unlimited budget (yours!) I'm sure he'd be willing to do what is necessary but are YOU willing to pick up that bill?

This is where a DIY approach is the only reasonable solution. Get it back and post pics and get a test meter to take some readings that we can use to identify the fault. Then purchase the parts and tools required to replace dud parts. See where this is going?