Can you help me figure out how to get into this area to fix a connection?

[Delicieuxz]

The front-right RCA connector for my PC subwoofer has lost its connection, and for a while it would flicker in and out of sound if I played around with pushing the connector, but now I can't get sound to come out of it at all. The speaker works fine when I plug it into another RCA connector, so I know it is the front-right RCA connector that's broken.

The RCA connectors for this subwoofer chassis are sealed inside this chamber.







I've tried to get into it by removing all the screws, and by trying to cut and melt the orange glue holding the circuit board in place, but I can't get any of the two accessibly back-panels (the PCB and the silver backplate) to slide out or move even just a little bit.

I'm thinking about going nuts with a grinder and cutting the whole piece out in a last-ditch effort to access the part that needs to be fixed. If the alternative is to buy a new subwoofer and speakers (which I don't really have the money to do), I might as well try that, first.

But I keep thinking, that this has to have a way that it comes apart, without resorting to drastic measures.

If anyone can help me to figure out what to do, I'd be thankful. Not only do I not have spare money for a new unit, but I also like the sound of this subwoofer and its speakers more than other sets that I've listened to.

[petehall347]

Re: Can you help me figure out how to get into this area to fix a connection?

maybe remove main pcb first .
look for hidden screws

[stj]

Re: Can you help me figure out how to get into this area to fix a connection?

uploading the photo's so they are actually visible to other users would help!

[R_J]

Re: Can you help me figure out how to get into this area to fix a connection?

Did you also remove the screw between the rca jacks?

[petehall347]

Re: Can you help me figure out how to get into this area to fix a connection?

there might be a nut under the knob .

[R_J]

Re: Can you help me figure out how to get into this area to fix a connection?

https://www.youtube.com/watch?v=1LRIzePlma0 just don't open it like he did by throwing it against the wall, he does mention he removed the screw and the nut, another site mentions there being a nut on the control, so pull off the knob and undo the nut

[Delicieuxz]

Re: Can you help me figure out how to get into this area to fix a connection?

uploading the photo's so they are actually visible to other users would help!

I uploaded them to Imgur. They show up on my screen, so maybe the Imgur server hosting them was down for a bit. Are they still not visible on your screen?

Did you also remove the screw between the rca jacks?

Yup.

there might be a nut under the knob .

Good point. I'll check that out.

https://www.youtube.com/watch?v=1LRIzePlma0 just don't open it like he did by throwing it against the wall, he does mention he removed the screw and the nut, another site mentions there being a nut on the control, so pull off the knob and undo the nut

Wow, a disassembly video of this old system, haha. Too bad he doesn't show the opening the part in question, here, but that nut under the knob is something that I missed before.

Also, he says that his metal backplate just fell off while he was removing the screws. I took the screws out of my metal backplate and couldn't get the thing to budge. Maybe there' glue holding it tightly into place. I'll try prying it with a bit of force. His video shows that there isn't anything attached to it on the other side, so I hope it will be safe.

The guy in that video sounds like Simon the Sorcerer.


Thanks for the help, everybody. I'll post an update after I've looked at it again, tomorrow.

[Delicieuxz]

Re: Can you help me figure out how to get into this area to fix a connection?

I opened that chamber up after removing the bolt and the screws, and pulling very hard with pliers while pushing the subwoofer in the opposite direction. There was a lot of glue holding it in place, and lots of crunching noises as I pulled it out. The metal backplate continued to stay stuck to the PCB after I had pulled it out. I separated them and cleaned off the glue.

I couldn't find anything visibly amiss with the RCA connector, inside or out, or with the PCB solder joints, but I reflowed the solder joints for the RCA connector, and then audio was coming out of the other speaker just like it should.

I've been playing audio out through the unit for a few hours, and it recently lost audio out of the one speaker again, but then it came back after a few minutes without me doing anything.

So, I don't know what exactly the problem is, though reflowing the solder got it generally working again... for however long.

Maybe I'll try removing the old solder completely, and applying new solder. Also, maybe I'll try replacing the connector with a new one.


The connector is like this.

[petehall347]

Re: Can you help me figure out how to get into this area to fix a connection?

remove old solder first ..re-flow is never too good on connectors .

[Delicieuxz]

Re: Can you help me figure out how to get into this area to fix a connection?

I just removed and replaced all the solder on the connector's joints, and now the same speaker isn't playing any audio. So, it's something other than the solder joints. I don't know what, though. My guess is that I should next try replacing the connector.

[Delicieuxz]

Re: Can you help me figure out how to get into this area to fix a connection?

So, I've used the system for many hours, and occasionally the right speaker momentarily comes on, sometimes for a few minutes, and then stops working again.

Also, when I have the right speaker connected, there's an electronic buzz coming from it. And when I connect it, there's sometimes a pop sound.


FURTHER... OK, I just found this out: The rear connector panel for the subwoofer contains RCA connectors for each of the L/R front and rear speakers, and also has the power connectors for the Front and the Rear speakers - one connector for Front and one connector for Rear.

If I pull the power jack for the Front speaker out a few mm, the sound kicks in from both speaks, and the sound from the subwoofer is still present. If I push the power jack for the Front speakers fully in, the sound disappears from the front-right speaker again.

Does anyone know what this indicates, and what I should be trying to fix? Does this mean that maybe one of the metal connectors inside the Front power socket is dislodged, and so a fully-inserted jack is not lining up and touching the metal part for the front-right speaker correctly?

[petehall347]

Re: Can you help me figure out how to get into this area to fix a connection?

probably needs re-soldering ..

[Delicieuxz]

Re: Can you help me figure out how to get into this area to fix a connection?

Today, I decided to attempt to desolder the RCA connector to access the 3.5mm front and rear power connectors, which I also removed.

It could have been that those connectors needed re-soldering, but I also wondered whether maybe the connector itself was worn out.


I didn't have a spare connector on hand, but I've typically only used the front speakers, with the front speaker power connector attached, without having anything plugged into the rear speaker power connector. So, what I did was desolder both the front and rear power connectors, and then swap them, so that the less-used rear power connector become the front power connector, and the front connector was moved to the rear connector's place.

I soldered everything back together really well, cleaned up the flux residue from the PCB, and reassembled the chassis and powered on the subwoofer. And it worked! It now sounds like a working stereo system should - and it sounds great compared to the effect I was getting for the longest time with the way I was half-inserting the front speaker power cable to get it to make sound from both speakers, which was leaving various audio layers missing from tracks.

It feels good to have it performing properly, again.




By the way, to remove the rear connector and light PCB (which is covered with a metal shield) so that I could access and desolder the RCA and 3.5mm connectors, this is the full process I used:

As shared by other forum posters, there's a hidden 10mm nut underneath the bass volume knob on the back of the subwoofer that holds the back connector and light panel in place. Pull off the bass volume knob with your fingers, or something to give you a good grip, and then use a 10mm socket to remove the nut and the washer underneath it.

Remove the subwoofer cover by taking out the 4 screws that are in deep holes in each corner of the read of the subwoofer. Once the subwoofer cover is loose, reach into the subwoofer chassis and disconnect the subwoofer speaker cable from the PCB by pressing the connector's clip with your fingers while pulling on the cable.

Unscrew the two screws holding the metal cover over the rear connector and light panel PCB. The metal cover then removes freely - and if it doesn't its because there's some orange glue holding it in place.

Use an xacto knife blade, or similar to cut the glue that's holding the metal cover, and also the rear connector and light panel in their places, and, after you've already removed that hidden nut I talked about, use pliers to pull the rear connector and light panel out, along its track.

Alternatively, you could use a soldering iron to melt the glue that's holding the rear connector and light panel in place. I used both a knife and a soldering iron to make it easy enough to remove by pulling the PCB out firmly with pliers.




While I had the unit disassembled, I made a note of all the filter capacitors, which I guess could start needing replacements sometime in the future. I'll post them here, in case anybody else happens to have an interest in refurbishing this unit:

6x 470uf 16v
4x 0.22uf 50v
4x 1uf 50v
3x 100uf 16v
3x 10uf 35v
1x 0.1uf 50v
1x 4700uf 25v


If I do further work on the system, I'll aim to replace the capacitors, the RCA connector, and the two 3.5mm connectors.


BTW, if a mod sees this: Could you please add "(Cambridge Soundworks subwoofer and speaker system disassembly and fix)" to the thread's title, so that anybody else looking for information on how to work with this unit can find this thread easily?

[sam_sam_sam]

Re: Can you help me figure out how to get into this area to fix a connection?

One more thing that not going to the land fill

Good job