Hi guys. I have a pair of Townshend Glastonbury speakers from the 1980s. They have been in regular use with no problems.
Well I accidentally nudged one of them and it fell over on its side onto a wooden floor.
The ribbon tweeter still works but the midrange doesn't. I believe it is a Jordan J125 or J150. What should I be looking for? I have the crossover and the driver unscrewed but can't see any dislodged wires. The crossover board seems intact.
What should I be looking for?
Thanks, Stephen
Well I accidentally nudged one of them and it fell over on its side onto a wooden floor.
The ribbon tweeter still works but the midrange doesn't. I believe it is a Jordan J125 or J150. What should I be looking for? I have the crossover and the driver unscrewed but can't see any dislodged wires. The crossover board seems intact.
What should I be looking for?
Thanks, Stephen
You can hope a crossover component fractured the solder. Using ohms scale of DVM probe from each component lead to each other component lead. Also from out to speaker terminal. Also from connector in to crossover terminal. Resolder any discontinuity. Wear safety glasses, solder can splash.
Also check continuity of the driver coil with more high powered diode scale of DVM. Look for coil movement when you first connect the probes. No movement, possibly you have knocked driver cone off center. If it doesn't push in and out gently with no friction, that could be true. Not much movement for a mid-range. 1 mm maybe. If friction, then new driver purchase necessary.
Also check continuity of the driver coil with more high powered diode scale of DVM. Look for coil movement when you first connect the probes. No movement, possibly you have knocked driver cone off center. If it doesn't push in and out gently with no friction, that could be true. Not much movement for a mid-range. 1 mm maybe. If friction, then new driver purchase necessary.
You have given me some hope. I will focus on the circuit board & maybe take this opportunity to replace and update the components.
Time to dust down my old solder station and re-train these (now) shaky hands into a worthy cause. 🙂
I noticed when I powered the speaker up that it 'clicks' a lot.
Thanks Indianajo
Time to dust down my old solder station and re-train these (now) shaky hands into a worthy cause. 🙂
I noticed when I powered the speaker up that it 'clicks' a lot.
Thanks Indianajo
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Before tracing a potential problem, hook up any old speaker to the midrange leads. You can save a lot of time if you find this replacement speaker works fine.
Did the magnet fall/brea off the driver?
I was reminded last night, removing some Philip’s tweeters the magnets were at the bottom of the box.
After a fall, this is the mst commn failure mode i have seen.
dave
I was reminded last night, removing some Philip’s tweeters the magnets were at the bottom of the box.
After a fall, this is the mst commn failure mode i have seen.
dave
Back in the early 70's I ran the service department in an Olson's Electronics store. As stated the biggest failure in car stereo speakers was the magnet, or magnet assembly falling off. I did see some where the ceramic magnet itself would crack creating shards that would seize up the coil movement. Of course, back then car stereos did not have enough power to actually hurt a speaker driver.
A few years later I started my 41 year "real electronics" career at Motorola. By 1974 I carried a two way radio and walked the plant fixing broken stuff. I often used the battery end of my HT220 walkie talkie as a hammer, and never hesitated to throw it at a rat in the company courtyard. When I did manage to kill the nearly indestructible radio, it was either a broken quartz crystal, or a detached speaker magnet.
Look at the crossover, and the magnet first.
A few years later I started my 41 year "real electronics" career at Motorola. By 1974 I carried a two way radio and walked the plant fixing broken stuff. I often used the battery end of my HT220 walkie talkie as a hammer, and never hesitated to throw it at a rat in the company courtyard. When I did manage to kill the nearly indestructible radio, it was either a broken quartz crystal, or a detached speaker magnet.
Look at the crossover, and the magnet first.
I suppose the magnet still is in place...
The impact also can have demagnetized the magnet, but my bet is one of the connections or solder joints broke.
"Shifted magnets" aren't all that uncommon in PA speakers that have been dropped. It's usually the first thing I check for when I see major cabinet issues.
Tubelab's description is spot on- the magnet either breaks loose or cracks, and very often the voice coil either rubs or (more often) is locked in place and won't move at all.
Not much you can do in that case, unfortunately. Check to see if the cone moves and if the voice coil rubs. If it rubs or doesn't move, you're replacing the driver.
Tubelab's description is spot on- the magnet either breaks loose or cracks, and very often the voice coil either rubs or (more often) is locked in place and won't move at all.
Not much you can do in that case, unfortunately. Check to see if the cone moves and if the voice coil rubs. If it rubs or doesn't move, you're replacing the driver.
The first thing to do is to swap the non working driver with the same unit from the undamaged speaker. If the mid still doesn't work then the problem is in the speaker (crossover, speaker, terminal), if it works then the problem is in the driver.
Ralf
Ralf
Its a moving part that is most likely to be damaged. Especially one with tight tolerances and one that is vulnerable to the force vector on impact. Did the speaker land on its side causing a tangential shear on the driver? Has the driver become misaligned with the 90 degree negative G's on impact, causing the voice coil to go off centre and bind?
To check:
1. play music loud through the good speaker and see how much Xmax the cone moves on the driver
2. gently push the cone and feel how free and silent it is doing the same range
3. push the damaged cone gently - is it binding?
4. switch drivers from side to side - use a battery to test freedom of excursions and displacements
5. put the undamaged side driver in to the damaged to see if it sings and to rule out the electrical aspects
6. if the driver on the damaged side is binding fix it so it glides free. Can the spider/magnet/cone alignment be adjusted? Can a gentle tapping opposite counter force be inflicted to carefully realign? Use excursion testing and battery on both drivers till the damaged side moves identically to the good side driver.
7. Make a wide base for both speakers so they dont get pushed over again.
To check:
1. play music loud through the good speaker and see how much Xmax the cone moves on the driver
2. gently push the cone and feel how free and silent it is doing the same range
3. push the damaged cone gently - is it binding?
4. switch drivers from side to side - use a battery to test freedom of excursions and displacements
5. put the undamaged side driver in to the damaged to see if it sings and to rule out the electrical aspects
6. if the driver on the damaged side is binding fix it so it glides free. Can the spider/magnet/cone alignment be adjusted? Can a gentle tapping opposite counter force be inflicted to carefully realign? Use excursion testing and battery on both drivers till the damaged side moves identically to the good side driver.
7. Make a wide base for both speakers so they dont get pushed over again.
First of all desolder speaker terminals from the other elements and measure DC resistance across them.
Touch terminals to a battery ones, does speaker click?
If you softly press cone inwards with fingertips, does it move or is it "frozen"?
Touch terminals to a battery ones, does speaker click?
If you softly press cone inwards with fingertips, does it move or is it "frozen"?
I spoke today with Max Townshend in UK, who designed these speakers way back in 1981. He suggested I test 6 ohms at the coil.
I will swap drivers and then, if need be, will test the crossover board.
Thank you guys for your input.
Such is the hi-fi community that YOU can just pick up the phone and speak with a guy who designed & built your speakers 40yrs ago. This is why I love hi-fi. A big shout out to Max Townshend!
I will swap drivers and then, if need be, will test the crossover board.
Thank you guys for your input.
Such is the hi-fi community that YOU can just pick up the phone and speak with a guy who designed & built your speakers 40yrs ago. This is why I love hi-fi. A big shout out to Max Townshend!
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Hi - this just happened. I was listening to a record, volume was low as I am still doing some work. Half way through the side the sound cut out. No drama, no pop, just as if I had hit the mute button (I didn't). I am the only one in the room. I am sitting at least 3 feet away from the amplifier. I have tried different inputs. I have plugged in headphones and they work fine. I am at a complete loss how this could even be possible. Can't be the cables can it? They wouldn't both cut out at the exact same time. I guess I can try to lay my hands on another set of speakers and try running everything through the AV Receiver to narrow down the issue, but what could even cause something like this to happen? Thanks.
I have a receiver that the amp portion one day just no longer worked. The pre-outs still work. After searching on line, I found several comments that indicated the speaker selector switch had a tendency to fail. Haven't fixed it yet, as it's not as simple to get to the trouble spot as I would have liked.
This hardly being a speaker fault probably belongs in another subforum. My 2ct? Protection circuit coming in, due to oscillations or DC output. If it's the power amp that is.