Polk SDA 1C malfunction

[GraphicFX]

Tweeters out on left Polk SDA 1C

Removed both tweets (SL-2000) one of them is not functioning, the other is, (battery click test) yet no sound when hooked back up. The rest of the drivers are just fine. (MW 6503, and MW6511). Removed the interconnect cable and no change.

Thinking it was a crossover problem, I removed the passive radiator to see if i could find a leaky cap.  no luck due to them being film caps.  These speakers had been modded using the usual mortite, dynamat, and seemingly modded Xover.

I don't know anything about the electronics nor do I know how to solder.

Any help or leads would be greatly appreciated.

Thanks in advance,
Andrew

[schwarcw]

Greetings!

Replace the SL-2000s with the RDO-194s.  I am surprised the Polks had modified crossovers and the original tweeters. 

I might even have a couple of RDO-194s.  I will check.

[GraphicFX]

Greetings!

Replace the SL-2000s with the RDO-194s.  I am surprised the Polks had modified crossovers and the original tweeters. 

I might even have a couple of RDO-194s.  I will check.

I have a spare SL2000 tweet, but I believe the problem is in the crossover.

I've taken this pic from the web. It is exactly how the xover looks in these SDA's. I'm doing this for a friend. The crossover in question is the one on the right of the picture.

[schwarcw]

Ah!  The crossover on the right has a polyswitch.  It's the orange colored disk about 3/8" in diameter.  Try jumping across the switch with a wire, two alligator clips.  If the tweeter works when you jump the polyswitch, remove it and replace it with a 0.5 ohm resistor. 

Do the same to the other crossover.

I know you may be on a tight budget but $200 for 4 RDO-194 tweeters will give you a nice improvement in the sound.

[GraphicFX]

Ah!  The crossover on the right has a polyswitch.  It's the orange colored disk about 3/8" in diameter.  Try jumping across the switch with a wire, two alligator clips.  If the tweeter works when you jump the polyswitch, remove it and replace it with a 0.5 ohm resistor. 

Do the same to the other crossover.

I know you may be on a tight budget but $200 for 4 RDO-194 tweeters will give you a nice improvement in the sound.

Read about but never thought about that polyswitch. I will test it tomorrow and get back with you.  Thanks for the lead. Lets hope that solves the problem.  Money is tight so the tweet upgrade will have to wait. Last year for his birthday I got him a replacement SL2000 from my 2B's This year, He's getting the other.

[F1nut]

These speakers had been modded using the usual mortite   

Do yourself a huge favor and get rid of the Mortite as it actually prevents the driver baskets from coupling to the cabinet. Replace it with Armacell or the like.

[Sir Thrift-a-Lot]

BTW, are the two tweeters by chance wired in series?   (Given the driver configuration this wouldn't surprise me.)   If so, when one goes out, they all go out.   Like Xmas lights.   You might pull one good tweet from the other cab and test before you get too deep into xover work.   Or just check the one tweeter with the bad one jumpered.   This may change the xover frequency, but at low volume for brief testing it shouldn't hurt anything.

[GraphicFX]

BTW, are the two tweeters by chance wired in series?   (Given the driver configuration this wouldn't surprise me.)   If so, when one goes out, they all go out.   Like Xmas lights.   You might pull one good tweet from the other cab and test before you get too deep into xover work.   Or just check the one tweeter with the bad one jumpered.   This may change the xover frequency, but at low volume for brief testing it shouldn't hurt anything.

Last year a tweet went out on his right speaker, the other worked fine (same speaker) I already tried reversing the two tweeters yesterday, and still no sound. I'm first gonna replace the bad tweet and see if that fixes it. If still no sound than I think I'm gonna jump the polyswitch and see what happens. unless someone disagrees with schwarcw's earlier comment.

I thank you all for your concerns and comments.

Andrew

[F1nut]

Replacing the bad tweeter will not get the other one working. The problem is most likely the polyswitch as Carl stated, so jump that first.

Replace that Mortite!

[GraphicFX]

Replacing the bad tweeter will not get the other one working. The problem is most likely the polyswitch as Carl stated, so jump that first.

Replace that Mortite!

After work i'm gonna jump the polyswitch if the good tweet works, than I will replace the bad one.  Thanks man. I really appreciate all yours amd carl's help and advice.  Oh and it's not mortite, its some thin grey sticky flat material on the flange of the baskets, I work for True Value and sell mortite, this is not mortite

[GraphicFX]

I'm a complete moron.

I reopened the 1C via the PR and no polyswitch. Just a 0.5ohm resistor. Thinking it was a bad resistor, I jumped it as recommended, and still nothing from the tweeters.  I Replaced the bad Tweeter, and still no sound from the tweets. Since I know very little of the xover electronics, I removed the IC cable and fiddled with the balance on the preamp. Right was fine, Left speaker.... Nothing from the tweets or the mains.  The culprit;  The left speaker wire from the amp had come out. The sound i was hearing from the left speaker was from the MW6511 SDA drivers. Hooked the speaker wire back in the amp, and Poof. all was good. Tested it via the balance and only the SDA drivers produced sound when the balance was to the other side.

I feel like a complete moron and deserve less respect than I may or may not have from you guys.

Thanks for all your help,
Andrew

[schwarcw]

Andrew, we all fall victim to the obvious!!  LOL!  I am glad the problem was resolved with a simple solution.  No loss of respect.  You worked to try and fix it yourself, asked questions and took the recommended action.  All is well!

Sounds like you have the Armacell as it is flat and black as you described.  Do you know who did the upgrades?  It looks like Trey's work.

Save up for the RDO-194s.  It is a worth investment.  Have you tried to upgrade the SDA cable?  It's cheap, easy and another worthy tweak.  The rings that Larry from Club Pok sells are a HUGE improvement!!  Another $200 investment that will amaze you!

I am glad your speakers are singing again!

[GraphicFX]

Thanks Carl,
Not my Speakers. They were purchased a few years ago from Matt, a fellow forum member. I don't know if he did the upgrades or not. He just said they had crossover upgrades, My friend plunked down his 500 and we hauled them home

Mine are 2B studios, I've upgraded to the RDO 194's and loved the warmth they brought out. Larry's rings are next.

Thanx again for your encouragement, Carl. I really appreciate it. Without you guys, I'd probably be listening to an 80's rack system.

G-d Bless and again, My deepest gratitude,
Andrew

[Sir Thrift-a-Lot]

I respect your honesty.   Some folks would be afraid to tell that story.

[GraphicFX]

I respect your honesty.   Some folks would be afraid to tell that story.

Thanks, embarrasing, but I thought you guys would get a kick out of it.