Trouble with Tweeter Array

Dan77

I have a pair of original SDA SRS speakers, and I'm not getting anything from the tweeters on the right speaker. I've ruled out pretty much everything except the crossover, and being pretty new to this, I was hoping I might get help on a few questions.

I saw that in this manual, there is reference to an "external fuse" on page 4.

http://vr3mods.com/uploads/SDA_Handbook_2011_Rev3.pdf

Do I really have an external fuse, and if so, where is it located?

I've also seen quite a lot written about polyswitches, but I'm having trouble determining if the original SDA SRS have one. Same question here - if I have one, how do I locate it?

Finally, if those two things aren't the answer, how do I determine what components of the crossover need to be replaced? (Unfortunately, the crossover for the original SDA SRS wasn't labeled, so any help visually identifying the components would be very helpful.)

Any thoughts on this would be VERY much appreciated.

Thanks!

F1nut

It looks like the board suffered from a fried polyswitch. Those lead wires have to be desoldered from the board to remove the crossover from the cabinet, so instead they cut them and used wire nuts to reconnect. All in all, a real hack job. So, yes the polyswitch is the blue disc. That clear jacketed wire is crap and has oxidzed, so it needs to be replaced.

You cannot use Gimpod boards with your model, so I hope your current board checks out ok.

F1nut

The SDA SRS speakers do not have a fuse, they have a polyswitch, which is located on the crossover board. There's a schematic posted here for your speakers, take a look and you'll find the all the values.

txcoastal1

http://forum.polkaudio.com/categories/vintage-speakers

Dan77

Hi guys, thanks very much for weighing in and for the links. Doing the best I can looking at the crossover and the schematics, I think I may have pinpointed the polyswitch. Is this blue circular component the right one?



If so, it would make sense to me that this is the problem, because this is what the other side looks like:



Not sure if you can tell from the picture, but it looks like someone had tried to cover the connections with electrical tape, but you can kind of see the little wires sticking out. It's pretty clear a previous owner had problems with this, because the whole crossover has been ripped out. Here's a pic of the whole thing, where you can see the wires have all been reconnected.



I'm guessing at this point the bottom line is I need to replace the blue circular piece, assuming that is the polyswitch?

Thanks again.

Nightfall

It looks to me like somebody replaced the original crossover that had no idea how to solder, look at all those wires just twisted together. What a mess. Do you know how to solder? You should get gimpod boards and rework both of your crossovers.

Dan77

Yeah, that pretty much matches my assessment. (The "what a mess" part.) Redoing the whole thing sounds like a fun learning project since I'm pretty new to all this, but I think patching for the moment and coming back when I have a little more time might be the most realistic way forward.

tonyb

What a hack job on nice speakers. I know you don't want to hear this, but it may be well worth it to just send the crossovers out to have redone. Couple guys here do it and are reasonable.

Dan77

Thanks for confirming. I've seen a number of places that people suggest simply removing the polyswitch and bridging it. I have a pretty reasonably powered amp (300W). Safe to go ahead and do that?

tonyb

Most but a resistor in place of the Poly. Hard to tell though if that's all the damage that's done to that board....so "safe" is not exactly a term that would come to my mind. Judging by the pics, who knows what else the previous owner did but hey....it's your dime so if you want to risk it, have at it. If they were mine, both crossovers would be on their way to someone who knew what they were doing.

pitdogg2

Looks to me that someone didn't have the inter-connect cable and maybe tried to wire the speakers to resemble a standard stereo speaker. Just a guess. But I had the same done to my speakers, the guy told me he "fixed" them to play correctly but my wire was hacked further up by drivers.

Dan77

Yeah, I'm sure you're right that having a professional redo it is the best way forward, but that's going to require some consideration regarding how much time and money I have to invest at the moment. How much should I expect that to cost, and how do I find someone willing to do it? I'm in the DC Metro area and haven't had much luck calling local shops.

Also, if I were to replace the polyswitch with a resistor, what would be the right one?

Thanks again.

codycatalist

Westmassguy is great at crossover replacement and upgrading. I would shoot him a PM or go to DHS speaker repair's site.

F1nut

Not sure Dan77 is still with us as he hasn't been here since Feb.29th.