Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 30th January 2008, 12:51 AM   #1
diyAudio Member
 
Join Date: Jan 2008
Default Speaker repair

Hi All

I have a pair of small Mission bookshelf speakers with one DEAD. Absolutely no sound when connected to amp. Tried switching with the other one that works, same result - nothing came out.

Is this problem common? I have a feeling that both the tweeter and woofer dead at the same time is quite seldom. Is the cross-over the culprit or something else?

I'd like to fix it myself. Any solutions or ideas would be welcome.

Thanks.
  Reply With Quote
Old 30th January 2008, 12:57 AM   #2
John L is offline John L  United States
diyAudio Member
 
John L's Avatar
 
Join Date: Oct 2001
Location: Cary NC
Check your wiring first, then the crossover. Incidentially, does the speaker have a fuse or circuit breaker?
  Reply With Quote
Old 30th January 2008, 01:16 AM   #3
diyAudio Member
 
Join Date: Jul 2003
Location: Indiana
Send a message via AIM to sauuuuuce
Default Re: Speaker repair

Quote:
Originally posted by patknk939
Hi All

Tried switching with the other one that works, same result - nothing came out.

Thanks.
So when you switched how did you switch? Did you put the "dead" cabinet on the live cabinet amp channel or the live cabinet on the "dead" amp channel? Or to put it another way.....does the problem move with the speaker or does it stay with the amp channel?
__________________
It wouldn't be what it is, if it wasn't what it was
  Reply With Quote
Old 31st January 2008, 07:14 AM   #4
diyAudio Member
 
Join Date: Jan 2008
Default Re: Re: Speaker repair

Quote:
Originally posted by John L
Check your wiring first, then the crossover. Incidentially, does the speaker have a fuse or circuit breaker?

Quote:
Originally posted by sauuuuuce


So when you switched how did you switch? Did you put the "dead" cabinet on the live cabinet amp channel or the live cabinet on the "dead" amp channel? Or to put it another way.....does the problem move with the speaker or does it stay with the amp channel?

I don't think wiring (I assume this refers to speaker cabling) is the problem because the problem speakers were tested by connecting to a pair of working speakers. The problem moves with the speaker when switched between channels. I did take out the tweeter/woofer and saw the crossover at the back of the cabinet but hadn't taken it out and not sure there's a circuit breaker or fuse.
  Reply With Quote
Old 31st January 2008, 01:12 PM   #5
John L is offline John L  United States
diyAudio Member
 
John L's Avatar
 
Join Date: Oct 2001
Location: Cary NC
Ok, if you know for certain that the problem is definately related to the speaker, not the cable or the amp, then you will need to pop the lid to the speaker, or remove the main driver so you can look in at the inner wiring.

You need to see if the wiring to the terminal, is sound. I find it highly unlikely that both the tweet and woofer would be gone all at the same time, and not have the other channel do same to the other speaker.

I still think that the odds are a loose connection. I could be wrong though.
  Reply With Quote
Old 31st January 2008, 05:59 PM   #6
Bobken is offline Bobken  United Kingdom
diyAudio Member
 
Join Date: Dec 2002
Location: UK
Hi,

A quick and cheap way of establishing if internal wiring and component continuity exists, is to briefly connect a single cell battery across the input terminals of the speaker. Just touch the terminals of the speaker with a battery using a piece of suitable wire to make the connection, for a second or so at a time, on and off.

So long as it is a single cell giving merely 1.5 or maybe 1.6V DC, there will be no harm to anything (except an active speaker, of course), and on making the connection briefly, there should be an obvious 'click' or 'pop' heard each time. Also, you should be able to see most diaphragms move briefly inwards or outwards when the battery is connected, and this is a good way of checking the 'polarity' of the driver wiring, although with the very limited movement of most tweeter diaphragms, this is not always easy to see.

If nothing at all visually or aurally happens when you try this out, either both voice coils have burned out or similar (which is less likely), or something has become open circuit within the enclosure which prevents the signals from reaching the drivers.

Regards,
__________________
Bob
  Reply With Quote
Old 6th February 2008, 01:26 AM   #7
diyAudio Member
 
Join Date: Jan 2008
Hi Bob

As suggested, I've just tested both the tweeter and the woofer with a battery. Both have "click" when connected to the battery. This proves that both in fact work. Therefore, the problem seems to come from the cross-over. I've also checked the wiring and the connection to the x-over, they are not loose. At the same time, I've taken the x-over out from the enclosure. The x-over just made up of 2 coils, two 5W 3.3ohm JF resistors, two 12uF 50V capacitors and one 4.7uF 50V capacitor. So, how am I going to test where the problem is? Thanks for your advice.

Pat
  Reply With Quote
Old 6th February 2008, 01:38 AM   #8
John L is offline John L  United States
diyAudio Member
 
John L's Avatar
 
Join Date: Oct 2001
Location: Cary NC
If both speakers are working, and you think it is the crossover, you are faced with either a completely fried crossover, where both circuits are fried, or the wiring leading to, or from, the crossover is shorted.

If the crossover is not fried, then the fact that both speakers do not work strongly suggests that only wiring that is used by Both drivers has a short. Just check the circuit up to the point where the line branches out to the high and low frequency drivers. If not that, then I would suggest a complete breakdown.
  Reply With Quote
Old 6th February 2008, 10:23 AM   #9
Bobken is offline Bobken  United Kingdom
diyAudio Member
 
Join Date: Dec 2002
Location: UK
Hi Pat,

That is a good start but are you saying that you don't get any clicks/pops if you connect the same battery across the input terminals to the speaker?

Even though the DC battery voltage will probably be 'blocked' by some intervening capacitors (at least in the tweeter circuit, anyway), you should still hear a similar or at least some noise when you touch the battery on and off the entire speaker unit's input terminals.

If doing this test, it is absolutely quiet, then you have isolated the problem to somewhere between the input terminals and the drive-units, which basically means in the x'over itself, or any connecting wiring between x'over and input (most likely), or possibly between the x'over and the drivers. As John L suggests, this latter situation is much less likely as there will be separate wiring from the x'over to each driver, and it would be rather unlikely that both sets of wires would have failed at the same time.

If it doesn't seem like there is an obvious problem with the 'shared' wiring from input to the x'over, then it will take a bit of work to identify which x'over component(s) is/ are the culprits here. In my experience, something going completely 'dead' as you suggest, is more likely to be a failed solder-joint or similar, as although individual components will sometimes fail, often (mostly?) they will still pass some sounds, albeit distorted or reduced in amplitude.

Do you have access to any test gear like maybe even a cheap multimeter, and are you able to solder and unsolder various parts in the crossover? If not, and you do establish that the problem is within the x'over itself, then I think you will need some help with this from a local technician, unfortunately.

Regards,
__________________
Bob
  Reply With Quote
Old 9th February 2008, 02:44 AM   #10
diyAudio Member
 
Join Date: Jan 2008
Hi Bob. I've done the test of touching the battery on and off the input terminals of the speaker. It's absolutely quiet. No click nor pop from both drivers. I have both needle and digital multimeters. I'm quite comfortable with soldering and de-soldering. I appreciate your further advice. Thanks.

Regards

Pat
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Speaker repair.. stevef51 Multi-Way 5 28th October 2008 08:23 PM
Speaker Repair dscrobe Multi-Way 7 11th October 2007 11:44 AM
speaker repair aarono Multi-Way 2 19th November 2005 04:30 PM
speaker repair aarono Multi-Way 2 30th March 2005 08:15 PM
Speaker Repair bhg41088 Multi-Way 0 17th December 2004 12:57 AM


New To Site? Need Help?

All times are GMT. The time now is 05:39 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2