Hi,
I have a set of polk rti6's that I purchased second hand a few years ago. They are in good condition and treated well, they dont get played too loudly very often. Since I've come home from college I noticed that one of the 6.5'' speakers isnt functioning at all. Figuring it was dead, I ordered a new one and installed it, but it still doesnt work. What else could the problem be? I've also tested to make sure it isnt just my receiver. The problem seems to lie entirely within the speaker. Thanks in advance for your help.
This should not be difficult to sort out. The crossover is second order, so the woofer will have an inductor in series with the woofer, the cap will be in parallel. There will likely be a zobel network also, which will be a series resistor and cap shunting the woofer. There is nothing in this circuit that would cause no output. If the cap were fried, it would be open circuit, most likely but the woofer would output sound, but it would then have a first order crossover rather than second. If the cap shorted it would fry your amp or send it into shut down.
So there are few possibilities. Inductors seldom fail, so there is most likely a bad solder joint. Do you have a meter? If so proceed as follows.
Check that there is continuity from the terminal to the low pass filter choke. Then check if there is continuity through the choke. The resistance through the choke should be no more than half an ohm. It would have to be pretty close to open circuit to have no sound output at all. Now check that there is continuity form the choke to the positive terminal of the speaker.
Then check that there is continuity from the negative input terminal to the negative woofer terminal.
As a final check make sure there is continuity from the speaker terminals to their respective input terminals on the back.
I bet you find a bad connection. If it is a soldered one, take it apart and re solder. Now you can get dry solder joints to inductor wire quite easily. The wire of the inductor coil is copper covered with a paint type of insulation. It can happen that this insulation is not sufficiently scraped off prior to soldering.
If it is one of the soldered connections to the LF choke at fault, take down the connection, and scrape off the insulation all the way round with a razor blade until you have bright copper all the way round. Tin the copper and resolder the connection.
In the unlikely event the choke itself is open circuit, you will have to replace it.
