DLUngurait Posted July 13, 2001 Share Posted July 13, 2001 Help! Just bought a used pair of 1988 LaScalas...brought them home, hooked them up...and there doesn't seem to be anything comming out of one of the tweeters. Is there a way for a layperson such as myself to find out if it's a K-77 M tweeter problem or a problem with the type AL balancing network? Does anyone know the cost of a new K-77 M from Klipsch (since there is no longer a parts list on this site)? PLEASE HELP...SOON! I waited nearly 20 years to get a pair of LaScalas...I was so excited...now I'm really bummed. I'M DESPERATE! Dave This message has been edited by DLUngurait on 07-13-2001 at 09:06 PM Quote Link to comment Share on other sites More sharing options...
WMcD Posted July 13, 2001 Share Posted July 13, 2001 Dave, Calm down buddy. You have a couple of real gems and you signed on to a good self help forum. Perhaps they were being sold because they were abuse and you've got something in need of repair. A fixer upper. I think it is possible the voice coil in the K-77 tweeter is ruined. But don't jump to conclusions. It is less likely you've got a cross over problem. I don't know your level of tinkering ability. This is good time to ramp up. You can't do much that would make things worse. First, check for connection between the crossover board and the tweeter. Sometimes the screws get loose or the connection corroded. Just snug things up with a screwdriver. Also, check that the wires are indeed connected to the tweeter. The next level of testing is to buy a multimeter from Radio Shack to check the resistance of the tweeter. This is pretty simple and I'd be happy to give you particulars if necessary. I'll assume your not experienced in this sort of thing at all. The multimeter will have a setting to test continuity. You touch the wands together and the multimeter buzzes (or tones) because there is an electrical connection. Then, all you have to do is touch the wands (test probes) across the terminals of the suspected tweeter. If the voice coil is burned out, you get no buzz. If it tones, you're okay, and the problem may lie elsewhere. If that is the case (no tone), the voice coil has been blown. However, Klipsch can fix this for you. Be calm, be happy. It ain't an unfixable problem. Regards, Gil Quote Link to comment Share on other sites More sharing options...
Jim Cornell Posted July 14, 2001 Share Posted July 14, 2001 I have a couple of blown K-77-m tweeters here, i was wondering if i can get diaphrams for them or toss them out!!! Id like to have them for spares for my cornwalls, i have a spare woofer now K-33-E!! Regards Jim Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 14, 2001 Share Posted July 14, 2001 Jim, DON'T toss out those K-77-Ms! They can be overhauled at a good sound shop. The diaphragm is about $22 from E-V and is still available. Klipsch will overhaul them for about $77 each, I believe. NOS E-V tweeters may be obtained from Layne Audio in Nashville, TN (of course) for about $110 http://www.speakersupply.com/ Sam at Techstar in Nashville will overhaul your tweeters and ship them back to you for a reasonable price. John Quote Link to comment Share on other sites More sharing options...
DLUngurait Posted July 16, 2001 Author Share Posted July 16, 2001 First off...THANKS GIL!...for the help so far... I had already checked the connections on the input terminals...they were snug. Wires leading up to the tweeter appear to be connected. Although the insides (where the balancing network and horns reside) are pretty dirty...lots of dust, dirt, and cat hair...there wasn't really any corrosion. Any suggestion on the best way to clean this area? I did use a Q-tip w/ alcohol to clean all of the input terminals. Called 1-800-Klipsch and they told me to order a new diaphram (said it was "highly unlikely" that I had a crossover problem also said that it was "easy" to install)...so I got out the credit card and ordered the replacement diaphram (I think $77 and 7 to 10 days delivery!)...but then I started to feel like a wimp...so went to Radio Shack and bought a cheap ($24) multimeter. I set the meter to "Continuity", touched the probes to the input terminals for the tweeter and voila!...I got tone! So I disconnected the leads to the tweeter input and touched the probe directly on the wire leading to the tweeter...I still got tone...Thought I even heard a little crackling comming from the tweeter when the probes where rubbing against the wires. NOW WHAT!?!...Could it be that there is too much dust in the drivers or the gap? I also managaged to snap off both of the "u" shaped leads that attach to the woofer input (they were pretty fragile)...should I get new "u" shaped leads or just strip off the old crimps and attach bare wire? Send in the Marines...I need help! Dave Quote Link to comment Share on other sites More sharing options...
DLUngurait Posted July 17, 2001 Author Share Posted July 17, 2001 HOLD THE PHONE...NEW DEVELOPMENT! (as if anyone else is just sitting at their computers waiting for news on this front) At the suggestion of my friend Mr. Bob...I tried attaching my speaker cables directly to the tweeter inputs and voila! I got sound comming from the tweeter!...I guess it appears to be a problem with the crossover...Al K. are you listening? Dave Quote Link to comment Share on other sites More sharing options...
WMcD Posted July 17, 2001 Share Posted July 17, 2001 We're making progress. The scratching noise from the tweeter when being tested for continuity is normal. A small amount of current is being passed through them by the probe. Re cleaning. I'd try a vacuum cleaner hose first. Also maybe blowing things out with a product from RS. Liquid Air or the like. Why don't you tell us the model of the cross over. It might have a fuse for the bass and another for the tweeter and mid. But you should be missing the mid if that one has blown. There might also be a tweeter protection device. Experts can tell you. I'm a bit to hear the spade lugs on the woofer wire broke. You can just reattach the wires as you suggest. Or RS will sell you some spade lugs and a cripping tool. Observe polarity in any case. Hooking an audio source as a brief low level test was okay but I'd be real careful running anything to the tweeter without the cross over. It could well burn it out. Gil Quote Link to comment Share on other sites More sharing options...
DLUngurait Posted July 17, 2001 Author Share Posted July 17, 2001 The model # of the crossover is "type AL network"...which I belive is still current in LaScalas so it can be purchased. I didn't see anything that looked like a fuse...but I'll check. Made another trip to RS today to buy some spade connectors and a crimping tool...just figureed it would look alot nicer. If I end up needing to get a whole new crossover...any of you guys who upgraded to ALK crossovers interested in selling me your old type AL's?...Yea, I'd rather get the ALK's myself, but then I's have to buy 2 of them...and although Al's price is certainly fair...I just can't cough up that much right now (wife would definately kill me!)...Sorry Al! Dave Quote Link to comment Share on other sites More sharing options...
DLUngurait Posted July 17, 2001 Author Share Posted July 17, 2001 OK..I managed to crimp on some new spade connectors and reconnect the woofer terminals. I tried something Al K. had mentioned to me today...feeding the tuner pink noise to the speaker and then covering and uncovering the tweeter to hear if it's working. There is some sound comming out of that tweeter...but only about 25% the amount that eminate from the other speakers tweeter. I'm sure this is an improvement from before...maybe from just cleaning the input terminals? Al also mentioned swapping either the tweeters or the crossovers from one LaScala to another as a sure fire way to isolate the problem. Dave Quote Link to comment Share on other sites More sharing options...
WMcD Posted July 17, 2001 Share Posted July 17, 2001 I sent DLU the schematic for an AL-3. All I have of that family. I see it has a tweeter protection gadget which is something in parallel with a 100 ohm resistor. (This in series with the lead to the tweeter.) One thought is that the protection circuit opened up and DLU is hearing some signal thru put via the resistor. If this is in the AL, is it not self healing? I don't know. This is all guesswork. Al would know better. So, perhaps jumpering out the protection unit will solve the problem. Of course, then there is no protection. Gil Quote Link to comment Share on other sites More sharing options...
DLUngurait Posted July 17, 2001 Author Share Posted July 17, 2001 Gil, I thought going w/o protection went out in the 80's! I'll check the schematic now. Dave Quote Link to comment Share on other sites More sharing options...
WMcD Posted July 18, 2001 Share Posted July 18, 2001 Yeah, I typed the word and knew, just knew, there were going to be comments. Us guys all think alike. My observation is that PWK went to steep cross overs and the tweeter protection after high power amps came on line and users had the means to blow out drivers. A close reading of the Dope From Hope did not actually say the new cross overs were superior in sonic performance to the old ones. Maybe they are, or maybe not. People like Al K. cross overs which have steep slopes. The point is that if the tweeter protection device is defective, it could be jumpered out. This would do no harm unless one is driving the system so hard that damage is a possiblity. Gil Quote Link to comment Share on other sites More sharing options...
DLUngurait Posted July 19, 2001 Author Share Posted July 19, 2001 Gil, Yea - Yea, I guess I just couldn't resist that one...there's alittle "Bevis & Butthead" in all of us (especially me!) I'm obviously a complete novice when it comes to reading electronic diagrams/schematics but...it would appear to me that the "type AL" network in my LaScalas are radically different and much more complicated than the "type AL 3" schematic that you were kind enough to send me. I tried tracing the wire path back from the tweeters to see in anything appeared obviously wrong or disconnected...and I couldn't tell if any of the gadgets in the path were protection devices. I think I will put off tinkering until the weekend...then I will take the speakers to the garage for a GOOD CLEANING!...I'm aliitle allergic to dust and having my head up inside these things is killing me...besides I can't help but feel that all that dust and dirt might be at least a contributing factor here...at the very least it will help me see better when working on them. I think I will go ahead and take out the tweeter, take it apart and try to clean it as well...any tips on the do's and don't's on this cleaning would be appreciated. Again...Thanks for the support so far! Dave Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted July 19, 2001 Share Posted July 19, 2001 Dave, I wouldn't recommend taking the tweeter apart to clean it. If you do, you'll likely damage the voil coil and commit yourself to a new tweeter or new tweeter diaphragm. KG Quote Link to comment Share on other sites More sharing options...
DLUngurait Posted July 23, 2001 Author Share Posted July 23, 2001 Hello Again, I received a schematic for the "type AL" network from John (thanks John!)but I can't really make heads or tails out of it...so here is what I've done in the meantime. Tried to vacume and dust as well as possible in the upper chamber where the network, squaker, and tweeter reside. Used a q-tip w/ alchol to try and clean as many wiring contact points as I could find on the network. Tried wiring from the bad speaker's network to the good speaker's tweeter...tried wiring from the good speaker's network to the bad speaker's tweeter...neither of the options sounded good to me - way too little level from the tweeters...this didn't make any sense to me...I thought for sure this would be the way to isolate the problem...but it didn't...so maybe BOTH the tweeter AND the network are bad? OK so here's where I expect to get some warnings from the experts: I was getting frustrated so I connected the tweeter to the squaker input (along w/ the squaker)...I actually like the sound! It definately gives alittle more level than my other speaker...but it's not as drastically different as they were before. I'm sure I'm risking damage to my tweeter since it's geting more power than it would if hooked up correctly...but I don't tend to listen at really high levels. Am I risking damage to the network or the squaker as well? I don't really notice any difference in the output of the squaker. Any thoughts/advice? Dave Quote Link to comment Share on other sites More sharing options...
djk Posted July 24, 2001 Share Posted July 24, 2001 http://www.klipsch.com/ubb/uploads/ak-3.gif Look at the connections on the 125µH coil.Heat them up with a big soldering iron.If either end of this coil has a bad solder joint the tweeter will play very softly. Quote Link to comment Share on other sites More sharing options...
jread Posted September 26, 2001 Share Posted September 26, 2001 The protection network in the Lascalas was intended for indutrial sound reinforcement usage. They are back to back Zerner diodes that turn on and short the sginal to the tweeter at high levels. If they short out then they will attenuate the tweeter signal. Simply remove the protection for home usage. Quote Link to comment Share on other sites More sharing options...
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