If it ain’t broke, don’t fix it <— we start here
If it’s broke, try to fix it
If you can’t fix it, replace a component to get it working again
If you can’t replace a component, replace the whole thing and cry
After a storm passed through, I noticed my home theater subwoofer had gone quiet. This sub has served me for 19 years and the amp itself was repaired once already in 2010. Totally worth the initial investment.
I’ll just replace it with something more modern!
After the initial sticker shock of replacing it - and let’s be honest with ourselves, upgrading - wore off, I started down the path of every DIYer/tinkerer. Can I fix it?
If it ain’t broke, don’t fix it
If it’s broke, try to fix it <— we’re here
If you can’t fix it, replace a component to get it working again
If you can’t replace a component, replace the whole thing and cry
In short (electrical pun), no. I did what I could with a multimeter looking for obvious signal path issues but finally succumbed to the fact that I would have to spend some money.
If it ain’t broke, don’t fix it
If it’s broke, try to fix it
If you can’t fix it, replace a component to get it working again <— we’re here
If you can’t replace a component, replace the whole thing and cry about it
Aaaaanyway, based on availability I settled for a 300W rated unit to replace the original 350W unit. But the new one was about 1" x 2" smaller. You could totally do this with 1/4" ply/mdf and any kind of saw in no time. But when you have a CNC router, every problem starts off looking like a CNC project.
I had some Kydex sheet laying around from a motorcycle license plate frame/mount I had done years back. The matte side matched near perfect with the matte veneer on the speaker cabinet. Not that it matters. Since the amplifier is partitioned off from the speaker’s internal volume, nothing about the physical design of this adapter will impact performance. Keep It Simple, Stupid
Some cutting detail for those who haven’t had the chance to cut non-organic materials yet. Also linked to the cutting tools I used from my favorite crack endmill dealer on eBay.
Material was Kydex thermoplastic (basically ABS) 0.118". Double-sided taped to a mini-spoilboard of MDF. I used the tape burnishing and clamping method regularly demonstrated by @corbin to ensure it stuck well.
Fastener holes were located 0.06" deep with Melin 10715 1/8" 2 flute fishtail downcut endmill @ 40ipm plunge 16k RPM. I didn’t punch all the way through because I wanted the M4 fasteners to have plenty of material to melt threads into. The fishtail design helps cut a nice flat, square bottom hole when plunging where a truly flat endmill might wobble on contact with the surface before taking a bite.
The profile cutouts were done with an LMT Onsrud 10-20 1/8" single straight o-flute @ 60ipm ramp (6°), 80ipm cut (full depth) 20K RPM. I used tabs but they were completely unnecessary as the larger chips from the single cutting flute packed the narrow slot plenty well to hold everything in place. The newly-formed chips created basically a perforated slot that secured against horizontal movement, but were easily and cleanly chipped away in 1/2" long chunks with a flat screwdriver blade. Made a racket on the dust collector impeller.
In the past I have used cool air (~10psi from the air compressor) to keep a 2 flute endmill and plastic cool. This time I wanted to test the theory that a single flute produces larger chips and if moved quickly, does not reweld the plastic back to itself. Also, I don’t currently have the ability to spray it with the dust shoe in place, and plastic shoots everywhere without bristles in place. I would say this was somewhere in between, which was plenty good for this little project.
Thanks for the support corbin. While this was a small project, it’s such a huge departure from tree carcass and rare that it always feels foreign. I’m sure there are CNCers here running production plastic parts that know a heap more than me. Looking forward to your first plastic project.
