SDA GURUS - Need Help Troubleshooting SDA-SRS! (No SDA on left speaker)

Polkvibes

HI folks. I bought a pair of original blade/blade SDA-SRS speakers (1985/1986) last November. Recently, I noticed that the left speaker basically has no SDA effect. I did the 'balance test' whereby I turned the balance all the way to the left - I got full sound from the left speaker and NO sound from the right speaker. The right speaker was working properly when I did this same test a few months ago -- i.e. the Right speaker SDA array was pumping bass frequencies when bal control was far left. Now it is dead. With bal control to the right, the left speaker SDA array is working fine and pumping bass freq.

With bal control in the middle, I get a *huge* SDA sound from the right speaker (sound from both arrays) and no SDA from left speaker - the left speaker sounds like a regular stereo speaker. Imagine you are trying to land a huge 4-engine jet and 1 of your 2 engines on the left wing goes down, lol. Similar feeling.

Note: I took reference readings on the back of the Right speaker posts w/ a DMM and all readings were spot on *except* IC pin 1 (large blade) to Red speaker terminal... the reading is supposed to be 0.00 ohm and I got 0.4 ohm -- but if I gently moved the wires around, the readings would jump as high as 21 ohm, before settling back down to 0.4 ohm

Note: I eliminated the IC cable as a problem -- also hooked up another preamp, same effect, so the preamp is not to blame.

Other note: Crossovers were professionally recapped (dude did a great job). Unfortunately, the crossovers were un-professionally installed by me, lol. I had to splice all the internal wires to remove the xover then had to resolder/rejoin the wires -- I suspect the issue may be a bad connection. (My instinct is to look at these four wires, which connect both mid-woofer arrays to the xover (2 for SDA drivers and 2 for stereo -- perhaps the issue is here???) See below pic for reference - the pic is from the old crossover before I installed the new one -- you won't see my crazy soldering job which is held together with "twine and wizard spit", lol. (I don't have pics of that right now).

Can anyone give a clue as to what may be going on? I need to make an educated guess before I open the crossovers -- I'd eventually like to rewire both speakers but don't have the time or skill right now.

I'd love to get this solved!!! --- it been driving me *nuts* because I don't think I've had the full SDA working together on both speakers since I bought them

I realize the problem could be in either speaker (or both). Please specify left or right speaker when replying, so I get an idea of where to start. Thanks,

pitdogg2

There shouldn't have been any reason to "splice" wires. Your best bet is to provide detailed pictures of the crossovers NOW and pictures of the splices.

My first instinct is to say
1. The problem is with whatever you did in the splice and solder, get your meter out and start doing continuity testing.
2. You are very lucky that whatever you have done didn't let the magic smoke out of your gear

pictures are worth 10,000 guesses of how "great" your work is.

Polkvibes

Edit: I just realized that the SDA array on the Right speaker isn't even working when balance control is center -- what I heard before are sympathetic vibrations from the stereo drivers. So, yeah, the entire Right speaker SDA drivers are not working under any tests.....

Polkvibes

Thanks - in hindsight I should've re-wired the whole speaker or at least soldered the old wires directly to the board, but I listened to the guy who did the crossover who said don't worry about it, just splice the wires... bad advice!!

I will try to take some pics but it ain't gonna be pretty - but no magic smoke, luckily. I'm clueless as to where to do continuity testing other than on the back of the binding posts.

One more thing... since I'll probably have to rewire the whole speaker(s) eventually, can someone tell me what the goop on the inside of the binding posts is? (pictured below) I have a heat gun but not sure if that will do the trick to remove the goop in case its something other than glue.

pitdogg2

It's hot melt glue to seal up the binding posts. It can be loosened and removed with 91% alcohol. It needs to be replaced if removed.

F1nut

The goop is there to help create an air tight seal. I see some of it is missing though.

You can apply denatured alcohol to the goop using a Q-tip. Let it soak for 5 minutes and the goop will peel right off. Be sure to reseal all the connections with hot glue when you're done.

The grip of the blade/blade sockets loosens over time, which may be your problem.

Polkvibes

Thanks for the replies.

I'm pretty sure the culprit is my hack soldering job, and based on what Pittdog said, I'm not gonna use the speakers anymore 'till this is sorted.

I thought the same thing about the IC cable... so I just tried pushing it in tighter (and holding it there), but the SDA array didn't kick in unfortunately.

I'm gonna have to bite the bullet and rewire the speakers. The tweets are straightforward, soldered directly the board. but the mid-woofers? Are they wired series or parallel? I searched but seemed to only find stuff for the 1.2/TL version. Thanks, I assume some type of wiring harness is in order, but that is daunting. My only DIY wiring experience is with guitars which is pretty easy.

I'm pulling Right SDA drivers now as we speak, just to test and rule that out.

F1nut

Pushing the cable in tighter isn't possible nor will that fix the loose socket grip. If that is the problem you have to work on the socket itself.

pitdogg2

Rewiring is not for the timid.

I suggest you use the wiring harness you have to design the new one.

One more time pictures of how it is now would be very helpful.
Maybe it could be a simple fix for the time being using some bu tt connectors to get it figured out first before you go all scorched Earth.

Polkvibes

F1NUT... okay so I should open the binding post and squeeze the two tabs of the IC connector together to tighten the grip? Is that what you mean? I should be able to manage that, lol.

Pittdog - yeah, I just tried to remove a driver to look at the wires and that alone presented a few problems (stripped screws, crimp connectors which are either corroded or locked onto the terminal, ugh), so I'm starting to realize that perhaps I should wait to do a full rewire. But I was able to see a basic wiring scheme (see below)



I originally purchased butt connectors to join the wires but those particular connectors proved to have a loose grip. I'll practice again on some spare wires - then I might be able to 'bypass' my soldering job and redo the wires with the connectors.

I will post some crossover pics in the next few days, but trust me, its a huge mess so I don't know if you'll be able to see what's what. I think the butt connectors will help.... problem is, there is so little slack in the stock wires that there's not much to work with. That's why I was thinking about the rewire -- but hopefully I'll be able to try the connectors. The state of the 'clear' tweeter wires is terrible -- they are sticky and stiff and, again, no slack.

F1nut

That's what I meant.

Polkvibes

Cool, I'll give it a try first. If the problem is solved, I'd be very happy! Then I could leave well enough alone. If not, I'll try to update this thread when I can get to those crossovers. Thanks again.

Polkvibes

I'm reviving this thread 'cause I finally had a chance to pull the crossover on my right orig. SDA-SRS. To remind folks -- in the OP I stated that the SDA array in my right speaker was not firing.

When I removed the crossover, I saw that the clipped green & blue SDA IC wires had come off. DOH!!!! However, I cannot discount the fact that those wires may have just popped off while I was pulling the crossover, rather than coming off weeks ago when I noticed the issue (again). This has been an ongoing problem with this speaker, and it seemed to exist when I first received the speakers, and even after I had the crossover recapped.

But the story doesn't end here -- I noticed something (potentially) *very* disturbing on the bottom of the crossover, while planning to replace the green/blue SDA array wires and the white/black stereo array wires (which are soldered in rather than clipped). There seems to be very little to no copper trace below the blue wire. (Please see 3rd pic below).

1. Could the blue wire joint/lack of trace pad be causing the problem with the SDA array?
2. If the answer is yes, how can I fix it? A jumper of some kind?
3. I noticed that there is an inductor wire joint very close to the blue wire joint. When I eventually replace the blue wire, do I need to make sure that both joints do not make contact? Or is there supposed to be contact between these two joints?

Keep in mind when formulating your response that I'm a novice at this, I am somewhat DIY-challenged, I can't read a schematic, and I only know basic soldering, though I try to follow 'best practices'.

One more thing, I tested wire continuity on both the SDA & stereo arrays (when they were disconnected from the crossover) and everything checked-out ok -- there was continuity and resistances were < 10 ohm. I also checked the SDA drivers with a 1.5V battery, and they responded favorably.







I really want to try to get this fixed this weekend, 'cause I've never been able to enjoy the full operation of these speakers since I bought them months ago, even after the crossovers were recapped -- very frustrating! I'm still holding out hope that the problem was just the green & blue clipped IC wires that popped off the back of the crossover!!!

Polkvibes

I'm reviving this thread because I finally had a chance to pull the crossover on my right orig. SDA-SRS speaker. To remind folks, in the OP I stated that the SDA array in the right speaker was not firing.

When I removed the crossover, I noticed that the clipped green and blue SDA IC wires had come off. DOH!! However, I cannot discount the fact that these wires may have popped off just as I was removing the crossover, rather than weeks ago when I noticed the problem. This has been a persistent issue with these speakers, it occurred when I first bought them and even after a crossover recap.

But that is only the beginning of the story -- while looking at the board, I noticed something (potentially) *very* disturbing. I was planning to replace the soldered SDA array green & blue wires and the soldered stereo array white and black wires w/ fresh wire. Then I noticed that the was very little to no copper trace below the blue wire joint. The blue wire connects to the SDA array. (Please see 4th pic below).





1. Could the lack of copper trace below the blue wire be causing the problem in the SDA array?
2. If the answer is yes, what can I do to fix it? A jumper of some kind?
3. I noticed that there is also an inductor wire very close to the blue wire joint. When I eventually replace the blue wire, do I need to make sure that the inductor joint doesn't make contact with the blue wire joint? Or are they supposed to make contact?

Keep in mind when formulating your responses that I am a novice, I am somewhat DIY-challenged, I can't read a schematic and only have basic soldering skills, though I try to follow 'best practices'.

One more thing -- I tested wire continuity for both the SDA & stereo arrays (while disconnected from the crossover) and everything checked-out ok. There was continuity and resistances in both cases were < 10 ohm. I also tested the individual SDA drivers w/ a 1.5 volt battery and they responded favorably.

I really want to try to get it fixed this weekend, because I haven't been able to enjoy the full-operation of these speakers ever since I got them last year and even had it recapped, very frustrating! I'm still holding out hope that the problem is just the green & blue clipped IC wires that popped off the back of the crossover!!!

pitdogg2

@westmassguy @VR3

Correct me if I'm wrong, would that be the SDA inductor, could these two be connected together?

That is UGLY someone mucked that up good !!

Polkvibes

I'm not sure it's the SDA inductor, but that's what I believe. When I sent the crossover out to be recapped, I told the guy to make sure that everything on the bottom of the board was clean -- 'guess he didn't pay attention. Unfortunately, its harder for me to find info on how to fix these online because everyone seems to have the 1.2/TL. I was hoping to figure this out, because then I'd be armed with info in case I have to contact the person who did the recap. I don't want to get rid of the speaker because they sound great even with the issue.

Polkvibes

Are you saying that @VR3 may be able to fix this?? That would be great.

pitdogg2

Polkvibes wrote: »

Are you saying that @VR3 may be able to fix this?? That would be great.

No! I'm simple asking a question to those two.
Could he fix it SURE but then you would have brand new crossovers and no more boards. Trey likes point to point.

Polkvibes

Ahh ok got it. So curiosity got the better of me and based on what you said, I pulled the left crossover to check (the left speaker is functioning correctly on both arrays). Lo and behold its still an ugly mess but it appears that all three solder points are connected -- the left inductor, the blue SDA wire and a fat cap. I'm gonna try to duplicate it on the right crossover.


I'll probably hold off 'till Saturday (tomorrow) in case anyone wants to chime in w/ info or cautions.

pitdogg2

Polkvibes wrote: »

Lo and behold its still an ugly mess but it appears that all three solder points are connected -- the left inductor, the blue SDA wire and a fat cap.

That's what I was thinking, that they were all soldered to one pad.

Polkvibes

Thanks, makes total sense. I'll update this post after I try to fix it. Hopefully I won't fry something in the process.

VR3

That right there is a mess.

Anything can be fixed though... just remember all a trace is, is a wire. The little holes with silver surrounding it is just where the coating over the copper has been removed and tinned. You can just as easily loop a lead around another lead or wire... clamp and solder and achieve the same goals.

Polkvibes

VR3, sounds good thanks. I have some spare wire leads from guitar caps that I may try to use. In that specific part in the pic it looks like there was a single solder pad, so I'm going by the assumption that the inductor wire, the blue wire and one of the nearby caps should all have continuity. I'm going to try the repair today -- but if that sounds wrong, hopefully someone will let me know here.

BTW I saw some of your crossover work in other posts, looks great. (I think it was the Abby one?) If you do SDA-SRS point-2-point ones, I might be interested at some point! Let's see if I can at least get these things working first.

Polkvibes

Fixed! Big thanks to VR3 and Pittdog for setting me on the right path. It turned out to be the God-awful soldering on the bottom of the board and the degraded PCB pads. For the first time since last November, I finally have SDA on *both* speakers at once, lol. Who knew? It sounds freakin' amazing. For people with turntables, I just listened to the 45 rpm version of Morrison Hotel and LA Woman -- and damn, if that isn't the biggest soundstage I've ever heard from these (or any) speakers! The sound is extending like 6FT from the outer edge of each speaker. Huge!!!