No sound from my tweeter

bored184

A while back I posted about a set of RTA 12s with the peerless tweeters for sale. I ended up contacting the seller a week and a half later while I was at the Bass Pro. He still had them so I went ahead checked them out. Cosmetically they were in pretty good condition other then a thick coating of dirt and grime on the crossover. However one driver was frozen and a tweeter wasn't working. This is probably why he still had them. I still bought them, albeit at a reduced price figuring it would be an easy fix. I checked the tweeter with an ohm meter and got an open reading. I ended up picking up a used peerless tweeter and installed it tonight. The problem is I am still not getting any sound from it. I checked the leads going to the tweeter with my multimeter and I get an ohm reading so I know there is a compete circuit. I also checked the fuse and its still good. Thanks to VR3 I have the parts to work on the crossover but I was hoping to here them stock for a short time before I got into the cross over during my spring break. Any ideas?

rpf65

Just because you have continuity in any electrical/electronic circuit doesn't mean you have a complete circuit. I'm not sure what the range is, so I won't comment on that.

Phasewolf

My guess would be that what ever opened the tweeter up took out other crossover parts and that you will need to replace them to make it work again.

Phasewolf

Check for a open poly switch my money is there. If it is open you can jump it and the tweeted will work once again.

F1nut

Did you check the "new" used tweeter? Did you test the fuse in the holder or out? If out, clean the fuse holder terminals, then try again. If all of that checks out, you have an issue on the crossover board.

F1nut

Check for a open poly switch my money is there.

He has a fuse, no polyswitch.

Schurkey

bored184 wrote: »

I checked the tweeter with an ohm meter and got an open reading.

Tweeter is dead, but you already know that.

bored184 wrote: »

I checked the leads going to the tweeter with my multimeter and I get an ohm reading so I know there is a compete circuit.

Don't use an ohmmeter. Set the multimeter to volts, look for signal on those tweeter wires while playing music or test signals.

bored184

Thanks for your input! The new to me but used tweeter measured 7.6ohms. Fuse checked out fine and cleaned the terminals, still no sound. I guess I will be working on the crossover tonight, I have never done it but should be fun :cheesygrin:.

lanchile

Good news, the tweeter looks good! Now check for the small round blue poly switch on the crossover, just jump it and you should have music!

Attachment not found.

Phasewolf

F1 the prints I looked up for his showed a poly which is why I said to look for it. From what I have read and seen some did and some did not.

bored184

I wish it was as simple as the polyswitch. Mine is an older set which has the fuse, the fuse and tweeter check out so by reason of dudection it must be in the cross over. As far as I know of there isnt anything else.

TennMan

Why not swap the tweeters and see if the problem follows the tweeter you suspect is bad?

txcoastal1

^^^^^ding ding ding.....+2

westmassguy

bored184 wrote: »

I wish it was as simple as the polyswitch. Mine is an older set which has the fuse, the fuse and tweeter check out so by reason of dudection it must be in the cross over. As far as I know of there isnt anything else.

The various schematics for the RTA-12 show three Mylar or Electrolytic Capacitors in Series with the Tweeter. There are also, most likely, a few small Silver Mica bypass caps as well. If there are indeed Electrolytics in the circuit, they are most likely the culprit.

bored184

Did they ever use silver solder on the old RTAs? Ive got a rat shack desoldering iron that wont even melt the solder. Ive attemtped this on the board and the driver thats shirfted. Ive been in discussion with Vr3 and tried mutiple ways to melt this stuff, still no luck.

westmassguy

bored184 wrote: »

Did they ever use silver solder on the old RTAs? Ive got a rat shack desoldering iron that wont even melt the solder. Ive attemtped this on the board and the driver thats shirfted. Ive been in discussion with Vr3 and tried mutiple ways to melt this stuff, still no luck.

The heat from the iron is dissipated too quickly by the copper traces and the board itself. You'll need a higher wattage soldering iron, and a de-soldering pump, which is what I use. Rat Shack sells a 50 watt adjustable soldering iron, and the solder pump. Set the iron to about 35 watts, and you should be fine. Don't set the iron to high/hot, or you'll end up burning the flux.

bored184

Here is what I have:
Desoldeing: http://www.radioshack.com/product/index.jsp?productId=2062731&filterName=Type&filterValue=Desoldering

Soldering: http://www.amazon.com/Weller-WLC100-40-Watt-Soldering-Station/dp/B000AS28UC

westmassguy

bored184 wrote: »

Here is what I have:
Desoldeing: http://www.radioshack.com/product/index.jsp?productId=2062731&filterName=Type&filterValue=Desoldering

Soldering: http://www.amazon.com/Weller-WLC100-40-Watt-Soldering-Station/dp/B000AS28UC

I never liked the bulb type solder sucker, whether attached to the iron's tip or hand held. I use the spring loaded pump type. The 40 watt Weller should do the job, but see if they have a flat/blade tip to heat up more surface area.

StantonZ

How about some solder-wick? As long as the iron gets hot enough, you should be able to soak up the solder without "sucking up" any trace.

westmassguy

StantonZ wrote: »

How about some solder-wick? As long as the iron gets hot enough, you should be able to soak up the solder without "sucking up" any trace.

Wicks are great for removing large amounts of solder, but there still may be solder in the through-hole, which is where the solder pump comes into play. The traces on the Polk crossovers are pretty thick, so I wouldn't wory about damaging them with a pump.

bored184

I was able to use my soldering iron and wick to get a majority of the solder off the board. There is still a thin layer of solder around the holes. Do I need to worry about getting all the old solder off or is there a point when it doesnt matter?

chefkungfu

Trial and error! Works all the time!

TennMan wrote: »

Why not swap the tweeters and see if the problem follows the tweeter you suspect is bad?

bored184

TennMan wrote: »

Why not swap the tweeters and see if the problem follows the tweeter you suspect is bad?

chefkungfu wrote: »

Trial and error! Works all the time!

I thought of that but I ended up checking the tweeter with an ohm meter. Since the meter read open I figured the tweeter was fried.

The odd thing though is that I put the new tweeter in, it to did not work. I knew it was good because I got an ohm reading of 7.6. What ever fried the tweeter also fried something in the crossover

StantonZ

bored184 wrote: »

I was able to use my soldering iron and wick to get a majority of the solder off the board. There is still a thin layer of solder around the holes. Do I need to worry about getting all the old solder off or is there a point when it doesnt matter?

Not unless the solder has some sort of visible contaminant in it; in the end, it all conducts.

chefkungfu

That's kind of odd, I hope you narrow down the problem! Can you see any visual damage to the xo? Any dark spots?
Just trying to figure out what went wrong.
I had to de-solder some resistors on an amp, there was some "burnt" resistors on mine. Logged on to parts-express, bought the parts and off to work I went on them. Still holding strong to this day, although I remove the amp periodically and give it a once over to make sure it still looks good.
Good luck with yours!

bored184 wrote: »

I thought of that but I ended up checking the tweeter with an ohm meter. Since the meter read open I figured the tweeter was fried.

The odd thing though is that I put the new tweeter in, it to did not work. I knew it was good because I got an ohm reading of 7.6. What ever fried the tweeter also fried something in the crossover