TONYTANG
TONYTANG
Posts: 2
I have ACOUSTIC 626 Speakers which have seldom been used for many years. Now that I would like to get regular use, I found that the Tweeter and Midrange Speakers do not work.
The problem has to be with one of 3 items, capacitors, Fuse or some gadget that rotates in the back of the speaker, how do I test these. Thinking that it might be a Capacitor problem, I purchased 2 of similar readings - cannot find identical replacements here in England - I held the new capacitors (not soldered) by hand with corresponding wires but still no sound from the mentioned speakers. I have tested these two speakers at low volume with the Bass wiring and they work, so the problem is with the other 3 items. I opened the Fuse container (Red Button in the back) but it does not look like a normal fuse. The other 2 "Rotating" items in the back, I am unable to dismantle it open to see what it does and if anything looks out of order. Can someone give me any idea of what I should do .
Thank you
The problem has to be with one of 3 items, capacitors, Fuse or some gadget that rotates in the back of the speaker, how do I test these. Thinking that it might be a Capacitor problem, I purchased 2 of similar readings - cannot find identical replacements here in England - I held the new capacitors (not soldered) by hand with corresponding wires but still no sound from the mentioned speakers. I have tested these two speakers at low volume with the Bass wiring and they work, so the problem is with the other 3 items. I opened the Fuse container (Red Button in the back) but it does not look like a normal fuse. The other 2 "Rotating" items in the back, I am unable to dismantle it open to see what it does and if anything looks out of order. Can someone give me any idea of what I should do .
Thank you
Comments
https://forum.polkaudio.com/discussion/179302/acoustic-control-corp-626-any-info-out-there
You may want to post your questions about the speakers in that thread.
2. JM Labs Electra 920.1; Sonic Frontiers Line 3 Preamp; Classe Model 25 amp; Sony HAP-Z1ES; Oppo 105D; Music Hall MMF7 and Acoustech phono pre; PS Audio Power Director; MIT S1 Cables
3. Polk LSiM703; Parasound JC2BP and A21; Sony 48" 4K TV; Wyred4Sound DAC 2; Oppo 203; Squeezebox Touch; MIT S3 cables
No holes in it?
https://www.diyaudio.com/forums/multi-way/250292-benefit-fixed-resistor-lpad-variable-lpad.html
Because they are devices designed to pass fairly high levels of power (essentially two rheostats in one package), dirty (oxidized) L-pads aren't always amenable to the traditional "squirt and hope" cleaning with a good contact/control cleaner (e.g., CAIG DeOxit) that one would typically use on a normal potentiometer or switch. This being said, it shouldn't hurt to clean one that way, and it might help. No guarantees though.
EDIT: Here, FWIW, is a tutorial of sorts on using DeOxit to clean hifi switches and controls:
http://audiokarma.org/forums/index.php?threads/the-idiots-guide-to-using-deoxit-revisited.207005/
The AR speakers use rheostats instead of L-pads, but the following link illustrates the "proper" procedure to clean a wirewound rheostat. This "should"
http://audiokarma.org/forums/index.php?threads/acoustic-research-potentiometer-restoration-guide-very-long-with-photos.306818/
Finally, L-pads are readily available from folks who sell speaker building/repair supplies. In the US, here's a popular vendor.
https://www.parts-express.com/cat/speaker-l-pads/306
Here's an L-pad serving suggestion
source: http://www.usspeaker.com/px-Lpad-1.htm
Each driver should be disconnected from the crossover to test.
Connect (or hold) one wire to the "-" terminal (actually, either terminal, for this test, it doesn't matter!) of the speaker driver and then connect (hold) the other end of that wire to the "-" pole of the battery. Hold the second piece of wire to theother pole of the battery. Now, while holding everything tight
Don't leave the battery connected for too long, because current will flow through the voice coil in the speaker under test, heating it and also draining the battery.
If the speaker driver is "bad", you won't hear anything.
The other, better (sort of!) way to test the speaker driver is with a "DMM" (digital multimeter) or an older VOM (volt-ohm meter), if you have one. Same procedure as the battery, except that you'll read the DC resistance of the voice coil in the driver directly. It should be a small but nonzero value (e.g., maybe about 6 ohms for an "8 ohm" speaker). If it is "infinite", the voice coil is 'open' (damaged or burned open).
Hope this is helpful!
PS Here's a video that may be helpful. This person uses a 9 volt "transistor radio" battery. This may be a little more convenient, but the higher voltage and current capacity of such a battery will be more stressful on the delicate voice coil of a midrange or tweeter. A 1.5 volt cell is a better choice, I'd opine.
You're definitely not short of verbal projectiles.
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