Mighty Favog Posted January 28, 2002 Share Posted January 28, 2002 All right guy, here we go. I've got a pair of KLF-20's. About two weeks ago I noticed that the right channel is not putting out the SPL in LF range that the left channel is. The woofers still move but they don't have nearly as much bass as the other channel. Here's what I've done so far to pin point the problem. 1) Switch the preamp to "Stereo Reverse". Same problem in same speaker. 2) Swapped speaker cables at the amp. Same problem in same speaker. 3) Physically swapped whole speaker (man these are heavy) since left channel has two walls behind it and right side only has one. Problem speaker in new position has same problem. 4) Removed crossover and looked for loose or broken connections. None I could see. Did find all three copper wires going to the transformer touching each other. Seperated those. Smelled for burnt components on crossover board. None. Reassembled. Same speaker, same problem. Could the (light blue) capacitor be shot? Any other test short of swapping crossovers would be welcomed (that would be a tremendous amount of soldering). Thanx. Tom ------------------ Tom KLF-20 Mahogany (Hotwired) McIntosh C33 Preamp McIntosh MVP-841 CD/DVD Rotel RB-1080 Amp Yamaha PF-800 Turntable/ Sure V15 Type V Cartridge Ortofon VMS-30 mkII Cartridge Stanton P888SS Cartridge Yamaha K-1020 Cassette dbx 1231 EQ H.H. Scott 830z Analyzer Monster Interlink 400mk II Monster Interlink 300mk II Monster Video 2 (DVD to TV) Monster Power HTS-5000 MIT Terminator 2 Bi-Wire Speaker cables Studio Tech U-48RW Cabinet Vibrapods Enough empty boxes for a fire hazard! This message has been edited by tblasing on 01-28-2002 at 11:11 PM Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 29, 2002 Share Posted January 29, 2002 If you have the warranty, send it back. Do you have a multi meter? You can probably chase out the bad component, BUT, things like resistors, you have to pull them off the board to check their resistance individually. Otherwise, you will read the resistance off the PCB traces as well as the resistor. (and whatever else in the path.) I'm not sure about Capacitors, whether you can measure them on the Board or not, but I do know that Capacitors have many more parameters. Like Equalivent Series Resistance, Capacitance, DA, DF and whatever else, there is more. About all can do with a DMM is check a Capacitor's resistance, maybe another thing, I don't know. A capacitance meter is needed for proper measuring, A good decent one could be spendy, there is cheap ones, the cheaper ones probably measure capcitance only to a certain value. And you would still probably have to pull it off the board to measure it. Did you notice if the capacitor you questioned was bulged or had leaked Electrolyte under it on to the PCB? That's a good sign of a bunk cap. Man, I hope somebody with a little more knowledge on troubleshooting chimes in here. That's about the best I can do. (I wonder if the crossover/amp in the sub, has a reversed polarity in part of the circuits when it was assembled?) A schematic would be very helpful also. Good luck! Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted January 29, 2002 Author Share Posted January 29, 2002 Thanks Mike, I goofed, the capaitor I mentioned is light green not blue. Anywho, I don't see any buldging or see any leakage. The only thing that comes close is the stringy residue from teh hot glue they use to hold things in place on the board. The biggest thing I saw that was wrong was that the three copper wires from transformer were all touching each other. I seperated them but it still has the same problem. Could this have permanantly shorted out the transformer? I ordered another crossover today at a cost of $86 (ouch!) I hope it comes already mounted on the terminal plate. I've also got the feeling that I'm gonna have it out with Uncle's Stereo in NYC. Uncle's told me back when I bought them that they have a factory warranty. They don't. They just have an Uncle's Warranty. I'll see how far push comes to shove with Uncle's reimbersing me. (not holding my breath) This message has been edited by tblasing on 01-29-2002 at 05:10 PM Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 29, 2002 Share Posted January 29, 2002 Okay, Were those 3 copper wires off the transformer bare wires crossing each other? Are these the secondary wires coming off the transformer? These would be the wires feeding the PCB, into some sort of rectifying circuit. The primary wires are hooked to AC supply. Anyway, if the transformer is shorted out, It should run hot, I'm not sure. (It seems if the bare secondary wires were shorted out, it would smoke the rectifying circuit.) My knowledge of transformers is not the greatest. I know that they are passive devices, and are more or less a couple or a few chokes wound together into one. With a iron core or whatever. Testing transformers is kind of a trip too. You measure the resistances/voltages in the taps, some math, etc.... There is enough members of the Thermionic set here, that someone should have good knowledge on transformers and how they work. And my Algebra really sucks! I would get the matter staightened out with with 'Uncle' before you dive in there with a soldering iron. I hope it was just a bad crossover. Thanks! Quote Link to comment Share on other sites More sharing options...
JohnA Posted January 29, 2002 Share Posted January 29, 2002 Be sure to test the bass drivers for an open voice coil. It one coil is open, you'll get diminished bass, but that driver will appear to move because it is in the same chamber with the working one. I seriously doubt the crossover is bad. John Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 29, 2002 Share Posted January 29, 2002 Where you been? This guy needs some help. John makes a excellent point there. Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted January 30, 2002 Author Share Posted January 30, 2002 Thanks John, I took you advice and took out both woffers. Then disconnected one lead from each one and tested for continuity at the connection tabs. There was positive continuity on both woofers so I guess the voice coils are fine. I figured that only one lead needed to be disconnected to create an open circuit (there should be a dope-slap on my head in there somewhere). After it got put back together I played something though them and there was no change (just in case there was a cold solder joint). When I had the crossover out before I touched up all the speaker connections there as well. Still scratchin' the ol' coconut... Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted January 30, 2002 Author Share Posted January 30, 2002 Mike, I forgot to follow up on your question. The wires coming from teh transformer are bare and a reddish copper color. From the board there are three holes they come from. Really there's four wires but two of them are coming from the same hole on the board and twisted together. The other two come from there own hole and attach to a different place on the transformer. Those are the ones that were touching each other. Odd though, I agree that there should have been a burnt smell somewhere but I couldn't find one. Hey Al K. ya listening to this? I could sure use some insight!! ------------------ Tom KLF-20 Mahogany (Hotwired) McIntosh C33 Preamp McIntosh MVP-841 CD/DVD Rotel RB-1080 Amp Yamaha PF-800 Turntable/ Sure V15 Type V Cartridge Ortofon VMS-30 mkII Cartridge Stanton P888SS Cartridge Yamaha K-1020 Cassette dbx 1231 EQ H.H. Scott 830z Analyzer Monster Interlink 400mk II Monster Interlink 300mk II Monster Video 2 (DVD to TV) Monster Power HTS-5000 MIT Terminator 2 Bi-Wire Speaker cables Studio Tech U-48RW Cabinet Vibrapods Enough empty boxes for a fire hazard! This message has been edited by tblasing on 01-30-2002 at 04:34 PM Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted January 30, 2002 Author Share Posted January 30, 2002 . This message has been edited by tblasing on 02-01-2002 at 08:19 PM Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted January 30, 2002 Author Share Posted January 30, 2002 . This message has been edited by tblasing on 02-01-2002 at 08:19 PM Quote Link to comment Share on other sites More sharing options...
mike stehr Posted January 30, 2002 Share Posted January 30, 2002 Tom. Dig through the archives at the AA boards. Tweaker asylum would be a good place to start. Type in some keywords relating to the problems you have. You could also post questions on the boards, but I think you will get better help by browsing through the Archives. It could give you some options on troubleshoooting. THANX! Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted February 1, 2002 Author Share Posted February 1, 2002 Just got th enew crossover at work today. I'll use a bunch of alligator-jumper clips to see if that's the problem before it gets soldered in. Let's Hope. ------------------ Tom's Money Pit Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted February 1, 2002 Author Share Posted February 1, 2002 Well, the network wasn't the problem. I guess I'll have to order two woofers Monday. ------------------ Tom's Money Pit Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 1, 2002 Share Posted February 1, 2002 But your woofers didn't have open voice coils, Right? The woofers work, you have a new X-over board, your narrowing it down to just the amp circuit now. You may want to see if that amplifier circuit in that subwoofer has any power going to it, or outputting power. Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted February 1, 2002 Author Share Posted February 1, 2002 Mike, I feel like an IDIOT!! The amp is fine. I switched cables and amp channels and that didn't seem to help. I was down to the drivers themselves. Partially blown?? Never heard of it on a woofer but then again, who am I? Anyway, got down and dirty again and decided to swap the woofers from left to right cabinet to see if the problem follows. Put it all back together and it sounds FINE!!! Plenty of bass! The only thing I can think of is that when I rewired the internals of cabs I got two wires on one woofer out of phase. That's the only thing that makes sence now. The right channel (the problem one) still has a teeny-bit less bass to it but I'm betting (like Pete Rose) that it's because the left channel is supported by a corner (two walls) and the right has only one wall. When the girlfriend gets rid on some of this ugly furniture (party pit couch that takes up an entire wall) I can once again puth the system back on the short wall where both speakers have a two walled corner. Man, I hope I'm not getting overly excited about a "fix" if it turns out no to be the problem. Kinda like putting on a new water pump on the car and finding out after four hours of work (I had more) that it wasn't the cause of the over-heating problem. Now I just have to figure out how to fix a stripped screw hole in the motorboard. Trying to save some skin on the ol' paws I used a cordless drill to take all the screws out and put them back. ------------------ Tom's Money Pit This message has been edited by tblasing on 02-01-2002 at 11:43 PM Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 2, 2002 Share Posted February 2, 2002 You might be getting more bass due to the that very fact you posted. Standing waves? There is a thread on that. You should be good to go. I know the water pump thing, My little truck dumped one about a month ago. The one I replaced it with, had a bind in the bearing, and squealed when I first got the truck going again. It made it about two weeks, the bearing gave out, and the impeller started flopping and caught a peice of the gasket. The coolant was gone quick. It had a warranty, and I replaced it the parking lot I bought it at. (Let them clean the coolant mess.) I think your safe, at least your not out of a sub. THANX! Quote Link to comment Share on other sites More sharing options...
Guest BobG Posted February 4, 2002 Share Posted February 4, 2002 The two wires twisted together are common just as you've pointed out. The other two were not shorted even though they may have been touching. The reddish color you mention is the varnish type insulation covering the wire. Quote Link to comment Share on other sites More sharing options...
Mlstrass Posted March 12, 2002 Share Posted March 12, 2002 <<<Now I just have to figure out how to fix a stripped screw hole in the motorboard>>> Couple of things you can try. Fill in the hole with a mixture of sawdust/glue and then reinsert screw once it dries. Drill out the hole and glue a small piece of dowel in place and then drill out and insert screw... HTH...Mike Quote Link to comment Share on other sites More sharing options...
Deang Posted March 17, 2002 Share Posted March 17, 2002 I wanna be smart like Mlstrass ------------------ dean Quote Link to comment Share on other sites More sharing options...
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