Odd Cooling

[Lazarus Short]

I opened up my JVC MX-1 tonight, finding that it needed to be blown out with compressed air - badly. I should think so, it is 23 years old. I'll get to that tomorrow, but I was also looking at the main heatsink behind this huge output block. The thing is bi-amped (main speakers + internal subwoofer), and below the main heatsink is what looks like a fan, presumably for when the heatsink gets too hot. I decided to have a look at it. There is a coil wound around the middle, and I could not find the vanes of a fan. Um, there's a surround at the edge of a circular diaphragm. This thing is a BELLOWS! Avoiding the hum of a fan, this thing is made to "puff" air at the heatsink!

Anybody else know of gear using this kind of cooling?

 

[fitz43]

I opened up my JVC MX-1 tonight, finding that it needed to be blown out with compressed air - badly. I should think so, it is 23 years old. I'll get to that tomorrow, but I was also looking at the main heatsink behind this huge output block. The thing is bi-amped (main speakers + internal subwoofer), and below the main heatsink is what looks like a fan, presumably for when the heatsink gets too hot. I decided to have a look at it. There is a coil wound around the middle, and I could not find the vanes of a fan. Um, there's a surround at the edge of a circular diaphragm. This thing is a BELLOWS! Avoiding the hum of a fan, this thing is made to "puff" air at the heatsink!

Anybody else know of gear using this kind of cooling?

Have you got a picture of this device?

 

[Lazarus Short]

No, and I'm not sure how to take a photo, as I have to get my eye right down on it to see what it is, and I no longer have good macro photography gear. The thing looks a lot like a speaker, however.

 

[orange]

Dennis, doiing a search brings up a lot of those bulbous plastic all in ones with the funky looking blobby speakers...ugh. Either that or an AV thingy with a hard drive abnd DVD recorder DR-MX1.

Need you to take a picture of any kind and clarify your model number. Find a good resolution setting but don't make the photo filesize ungodly, vBulletin will have a fit and or it will take forever and the server will slip a Shugart.

PS Are you sure that it just didn't try something iwwegal and wose it's widdle mind?

 

[Lazarus Short]

OK, since I have some interest here, I dug out the Olympus, and did the best I could. The model number on the back, btw, is CA-MX1BK. Only two things hold it back: mediocre stock speakers and too few inputs. When they were new, I saw one in a Dillard's for $1,000. Photos follow, the speakers, the front, the back, a view of the heat sink and the cooling unit (says "JVC"), and the innards of the cooling unit. It looks like a wound coil surrounded by a ring magnet, at least that's my guess. It's like a speaker designed to puff air.

 

[Lazarus Short]

Yeah, that's not good macro work, in my opinion, just the best I could do with what I have to work with.

 

[fitz43]

OK, since I have some interest here, I dug out the Olympus, and did the best I could. The model number on the back, btw, is CA-MX1BK. Only two things hold it back: mediocre stock speakers and too few inputs. When they were new, I saw one in a Dillard's for $1,000. Photos follow, the speakers, the front, the back, a view of the heat sink and the cooling unit (says "JVC"), and the innards of the cooling unit. It looks like a wound coil surrounded by a ring magnet, at least that's my guess. It's like a speaker designed to puff air.

Thanks for the pictures. That is a strange looking piece. Does it continuously move when the unit is in operation? Is it sucking or blowing?

 

[laatsch55]

Suppose that would depend on which side you were on eh??

 

[fitz43]

Suppose that would depend on which side you were on eh??

haha. How about outside looking in?

 

[laatsch55]

Ah, now that we are properly referenced and oriented, I'm kinda curious too.

 

[laatsch55]

Equal Opportunity Cooler-----Sucks and Blows....

 

[orange]

It's quieter than a conventional fan, I would bet though. Oddly enough it resembles the inside of a hard drive more that what I suspect is an electrostatic fan (think that tall, skinny tower thing that says it's an air cooler, like you'd find at a Walmart or other stores.

Your full servicing information file including the operating instruction can be found here:

http://freeservicemanuals.info/en/servicemanuals/viewmanual/JVC/CAMX1BK/CAMX1LBK/

Click on your model name in the box below the cover picture (CA-MX1BK) to download the 177 page 18.1 Mb PDF file...the parts lists start somewhere past page 50.

This is where we come in to find the thing and ID it.

PS This manual is dated August 1990 and JVC isn't necessarily going to be able to reference it as eletronics companies don't always carry their baggage with them when they are bought or merge. They and new partner Kenwood are notorious for this as are many others, except for maybe Pioneer and Sony (and they found any sources they could to rebuild their library at Sony, one of yet another dumbass moves they made in the 90s).

 

[Lazarus Short]

Thanks, Steven! You are one helpful fellow!! I have a hardcopy owner's manual, so with this pdf, I suppose I could keep this unit going for ever. Let's see, CD player is not working, tuner OK, tape drives...not too sure. Amp is solid...well, wait a minute - the THD figures in the manual are a bit high: 0.9% ?!

 

[orange]

Page 93/136 *don't know where I came up with 177 pgs It's called a POWER ENGINE!

Yes, it's like an electrostatic panel that cools by vibrating air.

 

[Lazarus Short]

Page 93/136 *don't know where I came up with 177 pgs It's called a POWER ENGINE!

Yes, it's like an electrostatic panel that cools by vibrating air.

No, I don't think it's electrostatic, but the diaphragm moves by the ring magnet being actuated by the coil. Operating at 10 -16 hertz, the weight of the magnet does not hurt performance, and the stationary coil allows for gobs of power. Also, to answer the question someone raised, the diagram indicates that it only blows.

 

[orange]

Well, yeah, it's still a funky subwoofer that won't rumpshake a Hyundai but probably has an added benefit of annoying house pests.

 

[orange]

Here's the entire search query I used, see if you can find any parts you might need still available new or used.

https://www.google.com/search?q=JVC...&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=

 

[Lazarus Short]

I got the unit installed in rather tight quarters, and it played fine. Today, the right channel dropped out, and then the left. Aaaaaaaaaaaargh! I'm so tired of this! It's ALWAYS the cheap spring-clip speaker terminals in the back of the unit. Thick wires don't work. Thin wires don't work. IT'S DEWERDIE TIME!!

Out with the Dremel! Out with the soldering tools! I cut off the outer portion of the terminal strip with the Dremel and a tiny cutoff wheel. Zip! Pry off the plastic - hey, it makes its own isolation block. I put a blob of solder on each "spring," tinned the ends of the wires, and sweated them in place. Nice and solid - no more intermittent opens here, no sir!

With the MX-1 back in place, the sound is wonderful, and I can hear why people bi-amp. I thought that this winter, with all my main system gear packed, I would have to settle for less. However, with the MX-1 connected to the Missions (now the Heresys) in place of the "A" speakers, it sounds very good, in spite of the rather high THD rating. I'd say the amp section is very musical.

EDIT: It's always one or two days of bliss with this thing. I powered it up this morning, the right speaker was dead, and the left was intermittent. To get it to work, I had to turn the balance to one speaker, and crank the gain way up. After that, everything was fine. I think there is a connection in each Heresy which has too much resistance. The Missions are going back in, and the Heresyes are getting a tear-down. Is life with vintage gear always like this?