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PostPosted: Wed Jan 24, 2018 10:22 pm 
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Joined: Sun Jan 25, 2015 11:44 pm
Posts: 383
Location: Calgary, AB, CA
Re-capping my CM-1030’s and I have some caps where the printing is illegible. I can read 97, 150, 11.5, however I’m not sure about the following 5.7, 4.4 & 24
Anyone have a schematic?


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PostPosted: Thu Jan 25, 2018 6:08 am 
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Joined: Sun Oct 26, 2008 5:10 pm
Posts: 72
Location: Ottawa, ON, CA
I don't own 1030's but a REALLY long time ago I owned CM-1020's that I bought new. Lovely sound and beautiful cabinetry.

This article - https://forum.audiogon.com/discussions/ ... 0-speakers - mentions SpeakerMart in Ottawa (which still exists (or at least did last summer) - I live in Ottawa).

snip from article:

I have a factory original service-shop wiring diagram for the 1030's and would be happy to share. The only caveat is that I believe that these speakers went through at least one mid-life revision to their crossover - so the diagram may not match yours.

I would also highly recommend a shop called Speakermart here in Ottawa. They did the full refurbs for me. They also have mapped-out wiring diagrams (proper ones) that they used to repair any of the CM line of speakers. (There was also the CM1010 - which had the novel woofer brass screwed-in "plug" that would change the woofer's characteristics. They have spare plugs!)

end snip....


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PostPosted: Thu Jan 25, 2018 6:33 am 
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Joined: Thu Jan 13, 2011 11:29 am
Posts: 695
Location: St.Catharines, ON, CA
Schematic is online though you have to sign up to view or download.

G


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PostPosted: Thu Jan 25, 2018 6:56 am 
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Joined: Fri Mar 30, 2007 9:41 am
Posts: 4282
Location: Ingersoll, ON, CA
I owned a pair of CM-1030. Lots of good points but several problems that lead me to sell them.
The tweeters were prone to frying. Koss had me ship a defective tweeter to them and determined that the tweeter could have been more "robust".
I forgot how many times I replaced them.
The contour switches were brittle and broke with shocking ease.
They also would blow their fuse at levels that most people would consider safe and sane. Again, the good folks at Koss gave me a good supply of fuses.
Problems aside, I have fond memories of the CM-1030. The cabinetry was absolutely beautiful and played within their limits, they were quite engaging.

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PostPosted: Fri Jan 26, 2018 11:18 am 
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Joined: Sun Jan 25, 2015 11:44 pm
Posts: 383
Location: Calgary, AB, CA
mahatma1 wrote:
I owned a pair of CM-1030. Lots of good points but several problems that lead me to sell them.
The tweeters were prone to frying. Koss had me ship a defective tweeter to them and determined that the tweeter could have been more "robust".
I forgot how many times I replaced them.
The contour switches were brittle and broke with shocking ease.
They also would blow their fuse at levels that most people would consider safe and sane. Again, the good folks at Koss gave me a good supply of fuses.
Problems aside, I have fond memories of the CM-1030. The cabinetry was absolutely beautiful and played within their limits, they were quite engaging.


I've replaced the switches and have had no issues with the tweeters, however I do have a couple spares. I would like to do the caps to see if they could replace some of my keepers at the moment. I just finished a set of 1020's and they didn't make the cut, but came across these and thought I'd give em a try...


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PostPosted: Sun Jun 03, 2018 9:17 am 
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Joined: Sun Jun 03, 2018 9:11 am
Posts: 1
Location: Westerville, OH, US
Update 6/4/18: Jeff provided the answer to the switch: Philmore 30-172 is still available, and is an exact replacement.

Still missing the hardware (bushings?) that hold the switch paddles inside the little holes in the wood.

Have today discovered the crossovers need some repair.>>

Scoop --

I know your post above was three years ago...

I'm looking for a complete set of new or used-but-working switches (OEM or, better yet, exact replacements) for a pair of Koss CM/1030s.

And the threaded bushings that held the switches in place.

The Radio Shack link above appears to be dead.

The pair I'm hoping to restore are otherwise in Near Mint condition, so my fingers are crossed that I can bring them back to life.

Cheers!

Bob


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PostPosted: Fri Jul 20, 2018 6:52 am 
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Joined: Wed Dec 23, 2009 6:29 pm
Posts: 4
Location: Orleans, ON, CA
Anyone with questions about the Koss CM Series is more than welcome to contact me using this email address: junk666email@hotmail.com.

The online schematic for the Koss CM/1030 is a so-so scan of the only known Koss-original - which I happen to have. I can email you a hi-res version if you need it.

SpeakerMart here in Ottawa is still my recommended place to go for a pro refurb. Tell Bill I sent you! (If you are out West, I can recommend a place in Vancouver if need be.)

My current advice, when refurbishing a pair that's never been done before, is to replace all of the resistors AND all of the caps. It used to be to simply replace the caps if they've drifted out of tolerance. However by now, all of the originals, if not yet out of tolerance, will soon be (as I found out with a pair that had a resistor-only refurb only a few years ago). Best (and cheapest in the long run) to do them now.

Jeff Mackwood


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