Two Receiver Dead in One Day

There shouldn't be a buzz at all, clum or otherwise. Just a click (small speaker) or thump (big speaker).

On the buzzy speaker, try gently pushing the cone by hand. Does it seem gritty or smooth?

(I've been living in GB for nearly 20 years, and I've never heard "clum" before.)

When I pushed the cone by hand it was pretty stiff, would need to give it a bit of force before finally moving. I get the multimeter today so will do some readings tonight of the woofer and the tweeter. Should I test anything on the crossover?
 
Sorry, clum is a British word for stiff. A very short almost silent stiff buzz. On the working speaker, I get the click/thump when the speaker extends itself.
So this word Clum is it used in a derogatory way to describe a part of male human anatomy ever ?

I can just hear it now in a sentence...lol
 
When I pushed the cone by hand it was pretty stiff, would need to give it a bit of force before finally moving. I get the multimeter today so will do some readings tonight of the woofer and the tweeter. Should I test anything on the crossover?
Not a good thing if it's stiff it's rubbish
 
When I pushed the cone by hand it was pretty stiff, would need to give it a bit of force before finally moving. I get the multimeter today so will do some readings tonight of the woofer and the tweeter. Should I test anything on the crossover?
It should move a short distance easily and smoothly, with increasing spring resistance the further you push it. It should spring back immediately when released. If it seems stuck, requiring some force to let go or it seems gritty when it moves, that can mean the voice coil has burnt out -- possibly then shorting out against the speaker basket in the process -- and is jamming the cone.
 
I had this happen to me recently.

In my case it was a bad outlet. But that was, as I understand, a pretty rare circumstance.

Check your interconnects and speaker cables. Have you used any other sources besides your turntable?
 
Should I test anything on the crossover?
Crossovers are normally fairly indestructible but crossover capacitors can occasionally short out. Once the speaker elements have been removed, check the resistance across the speaker terminals with your meter. It may very briefly show some resistance, then should be infinite.
 
There is a CR9 crossover component on eBay I can get for $20 if I need it, going to check things with the multimeter tonight and see what I find - I loved the sound of the CR9 (happily admit it was one of the first sets of speakers I heard so I'm not experienced!) so going to try and fix them.

I'm probably going to get another pair of speakers as well from my wish list - a few KLH's around the SF area for me to check out.

I was tempted to get a solo Dynaco A25 to go with my solo working CR9 - been dying to try out the A25s after reading everything online.
 
Okay so here are the readings:

The Good speaker only gave me 3.6 ohms on the terminals on the back which is worrying...

The bad speaker gave me 0.4 ohms on the terminals on the back

The woofer gave me 0.1
The tweeter gave me 5.4
The capacitors on the crossover gave me 4.6, 10.5, 0.8, 0.3 (from little to large capacitor)

So.... looks like the woofer is dead. Do I also need to recap the crossover?

And the 3.6 on the "good" speaker - should I be worried? Should I take that apart and see what the readings are?

In other news - I'm going to (hopefully) pick a pair of Dynaco A25's this week so ill have those also!
 
Doubt there's any problem with the crossover unless you see something obviously busted or leaking from the caps, etc.

You shouldn't be getting anything close to a 4 ohm reading from a Boston CR9, unless of course those are not the original woofers. I would take the woofer out of the good one and measure it to be sure, but generally speaking the speaker as a whole will measure roughly the same resistance as the woofer.
 
Hi,

I have a few questions.

1) What are your meter settings?
2) When you measured the good speaker, what was your meter set at?
3) How did you measure the capacitors?

It definitely looks like your woofer is shorted out. I’m questioning your results on the good speaker. That seems too low on what I’m assuming is an 8 ohm speaker.

If you have to play something on your amps, make sure you use known good speakers. You want one speaker on the left “A” side and the second on the right “A” right side. Earlier, you were only playing one channel of a stereo signal, so you weren’t getting all the sound. Also, make sure that what you get are 8 ohm speakers. I wouldn’t plug your Boston’s until you’ve figured out what’s going on.
 
The Good speaker only gave me 3.6 ohms on the terminals on the back which is worrying...
Not necessarily. Sounds about right for a 4 ohm impedance speaker element. Is it a 4 ohm speaker element?

Or are you measuring the whole speaker unit? If so, it's probably fine.
The bad speaker gave me 0.4 ohms on the terminals on the back
Shorted.
The woofer gave me 0.1
Shorted.
The tweeter gave me 5.4
Sounds about right for an 8 ohm speaker element. Is it an 8 ohm speaker element?
The capacitors on the crossover gave me 4.6, 10.5, 0.8, 0.3 (from little to large capacitor)
Are you measuring inductors or capacitors?

More useful, at least to start with, is to disconnect all the speaker elements and measure the resistance of the crossover at the speaker terminals. With all speaker elements disconnected, it should be infinite resistance (no conductivity) though it may briefly show resistance as the capacitor(s) charge up.
So.... looks like the woofer is dead. Do I also need to recap the crossover?
Unlikely.
And the 3.6 on the "good" speaker - should I be worried? Should I take that apart and see what the readings are?
It wouldn't hurt to do so.
 
Thank you, everyone, for your help - really appreciate the guidance and knowledge.

Settings - it's on ohms setting and auto-range

CR9 is an 8-ohm speaker so that's my concern with the 3.6 ohm reading on the "good" speaker

When testing the crossover (image below of the CR9 crossover from ebay) - I was testing each of the green capacitors using the silver connector to the board

@DaveVoorhis - so unsolder the tweeter and woofer from the crossover and then test the reading using the terminals on the back to check the crossover?

s-l1600.jpg
 
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Ill have the Dynaco A25s in the next day or two (fingers crossed) which are also 8 Ohms speakers (assuming they are in original condition and haven't had replacement parts - i might even take my meter and do some readings when I go test them) - so I can use those as a benchmark.

My Sony STR 6055 is also still busted - so that will be my next project to fix, although a receiver looks way more daunting of a task!
 
CR9 is an 8-ohm speaker so that's my concern with the 3.6 ohm reading on the "good" speaker
It sounds a bit low, but not necessarily too low. If the speaker element functions correctly -- the battery test is a good way to check -- then it's fine.
When testing the crossover (image below of the CR9 crossover from ebay) - I was testing each of the green capacitors using the silver connector to the board
These should show infinite resistance when the reading stabilises, though they may initially show a resistance value as the capacitor charges up. Make sure to test them with the speaker elements disconnected, or you may be measuring the resistance of the speakers rather than testing the capacitors.
@DaveVoorhis - so unsolder the tweeter and woofer from the crossover and then test the reading using the terminals on the back to check the crossover?
You can't just unplug the speaker elements from the crossover?

The crossover in your picture can be unplugged.

Normally, you should be able to unplug all the speaker elements, then measure the resistance across the leads that normally connect to the speaker terminals that you connect to the amplifier. That should show infinite resistance after allowing a few seconds for the reading to stabilise and the crossover capacitors to charge.
 
If that's your crossover in that pic I hope you labeled everything so you know where it goes!

You might want to post pics of the front and rear of the drivers just to confirm they are original. Or find some pics online of these speakers and verify for yourself.
 
generally speaking the speaker as a whole will measure roughly the same resistance as the woofer.
There is a rule of thumb, the speaker impedance is 1.25 x the DC resistance. So an 8 Ohm speaker should read 6.4, technically, but they do vary. 8 ohms and 4 ohms are a pretty broad spec.
 
So a little update for you. The woofer arrives next week so I'll work on the repair once back from Europe and let you know how I get on.

I got the Dynaco A25's today, was like Xmas come early, got them for $120 which I thought was a steal. Reading about 6.6 ohms on each so much closer than the Bostons. However, I actually much prefer the CR9s and IMO they sound much better in every way over the A25s. So I am going to enjoy the A25s for a while until I get both Bostons back working - maybe I got lucky and have a great pair of CR9s or maybe I just prefer their sound.

Anyways - more to follow once I am back from Europe and can fix the Bostons. Thanks again everyone for your help and support
 
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