Realistic Mach One questions...

[penkosey]

I've ended up with a pair of Mach Ones. The first thing I did was start looking up info about these. Pretty quickly I read about how commonly loved or hated this speaker is, that there are several mods that can be done to them, and the differences in the model numbers 4024 vs 4029.

I have some questions that I haven't found answered after looking around here extensively--

Mine are the (from what I understand) more desirable 4024s which apparently have a rubberized woofer surround less susceptible to rot (I've already read a bunch on how most people have to re-foam the 4029s). My woofers look fine. The cabinets are fairly banged up & faded...I think with some effort they could either be cosmetically rejuvenated with some wood treatment, or re-veneered--but that's a low priority right now.

Of the pair...one of them sounds fine--I'm even able to hear some difference turning the mid & treble knobs. The other one--I'm getting some crackling/dropout sound from the mid and hi when turning the dials...and I don't really hear anything from the woofer.

I guess this is where my questions come in. In my very, very limited knowledge--I would guess that I need to remove the controls & knobs and clean with DeOxit...? It sounds to me just like the crackling of pots people describe when they DeOxit their gear. I'm guessing maybe somehow the woofer connection got very corroded, or even came loose? Just wondering what I might be in for before I take these apart & peek inside.

Speaking of--I actually did half-heartedly start taking them apart...I got as far as removing the screws on the woofer and front control panel. They're still stuck firmly in place & I didn't try very hard to budge them. I'm assuming there's some kind of goop, silicone stuff sealing them in? Should I try to gently pry up with a putty knife? I was worried about scratching the speaker facing up trying to remove the parts, because the front face of the speaker seems to be some sort of soft black stuff--the sides and front edges are wood veneer, but where the actual horns/woofer are screwed, it seems to be some kind of black surface.

Everything I've read about these speakers seems to be about re-foaming them & replacing the capacitors & updating the crossover. What I'm experiencing here, I'm not finding any info about. Am I looking at a DeOxit treatment here? Could something have come loose inside, or a fuse fried?

Looking forward to suggestions. I may not be able to answer immediately because of being on my phone with a poor signal most of the time, but I will definitely be checking in on this thread! Thank you!


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[swechsler]

It's extremely unlikely that the woofers were siliconed in place, unless the previous owner did it. More likely it's some foam gasket or Mortite that's being stubborn. Some people have had luck using some dental floss as a saw to get between the frame and the cabinet, in order to cut through the seal.

Now, regarding the non-working speaker. While it's possible that Deoxit will fix the midrange and tweeter issue, it won't help the woofer, since there are no controls for it. What I'd do, once you've got the woofer out, is disconnect it from the crossover and connect it directly to the speaker wires coming from your amp. Then try playing some music and see if you hear anything. If you do, the woofer's probably OK and your problem lies with the crossover. Respond back here and we can tell you how to proceed.

 

[penkosey]

Thanks for the info. Just checking in here because my back is messed up and I haven't been able to bring myself to move these heavy speakers around.

If it is a problem with the crossover, are we talking replacing a capacitor or something?

Another question--the big horns (midranges) that are exposed at the top have dust going back in past the molded vents. The speakers were pretty dusty & the first thing I did was clean them as best as I could. How do I reach the dust in the horn speakers? I figure compressed air might damage something back in the horn. Maybe some kind of artist paintbrush?

Thanks...

 

[loudnclr]

try a small vacuum that you can change the hose to blow instead of suck on the outlets the air isn't so direct that's how I cleaned mine then wiped them with a denatured alcohol on foam swab as far back as you can

 

[sax6]

Just checking in here because my back is messed up and I haven't been able to bring myself to move these heavy speakers around.

Damn back aches... they make me unabled to buy some speakers and amps that would be a score but I can't put them into my car, get them out of the car then bring them in my basement.

Missed some pretty good score that way. But, hey, my back earns me my living.

 

[penkosey]

No kidding...I knew these things would be heavy, but they feel like they're filled with concrete!

 

[penkosey]

Thank you guys! I'll post some pics when I'm able to get the speaker disassembled.

 

[Porkloin]

I remember skipping church with my buddy Dave to go over to Radio Shack and ogle those monsters when they first came out. If only I could've afforded them at the time, I'd be swimming in trim just like the guy in the illustration.