TL;DR version: Tweeters on my right TSI-500 and my CS-20 seem to not be working. Thoughts on ways to confirm before calling Polk? All impedance are near 4.7ohms on all entire Polk TSI system. Details below.
For a long time I ran my 500s off of a Sony 2ch amp, running from the pre-outs from my Yamaha 765, and my sub off another external amp. The amp I was running the sub on died recently, so I decided to go back to my old setup. The "old setup" is running the 500s off my receiver and using half of the Sony to run the sub (I ran it like that for about 4yrs before getting my Yamaha.)
This Yamaha has never had the left and right speaker outputs connected, always ran the external amp. Once I hooked the subwoofer up, I got no sound out of the sub/Sony at all. Through troubleshooting the sub situation, I noticed a low hiss instead of the familiar higher pitched white noise from the Yamaha test tone. After switching the inputs around I found that the rights tower's tweeter works on all LCR channels, where as on the left tower and center I could not get any sound from the tweeters. The woofers all work fine and sound great.
I metered all the speakers in my setup and they are as follows. All readings were held for ~20s to stabilize readings:
Left TSI-500: (Terminals unlinked) Bottom Terminals- 4.7ohms, Top Terminals- No reading. Linked: 4.7ohms
Right TSI-500: (Terminals unlinked) Bottom Terminals- 4.7ohms, Top Terminals- No reading. Linked: 4.7ohms
Center CS-20: 4.9ohm
Rear left TSI-100: 4.9ohms, Rear right TSI-100: 4.7ohms.
The thing that tripped me up is that all readings are very close to each other. I was expecting a blown tweeter to throw off impedance. I was surprised to find all my TSI products to be below 6ohms... I expected a little bit below 8 but 4.7 seemed low, but the consistency reassured me. Also on the towers, I was unable to get a reading from the top terminals, which I'm pretty sure are the tweeter terminals. The jumpers, or "links" on the towers are 4" lengths of 12awg instead of the stock brass jumpers.
At first I thought my old Sony amp could have fried them, since I'm now not getting any sound out of the sub, but I never had the center hooked up to the Sony. I know things happen, I'm not bitter at all, just trying to get to the bottom of it. I know I haven't had these for more than 5yrs, so I plan on calling Polk about warranty work. Thought I would ask your guys' opinions beforehand. I'm not opposed to opening up the towers if I have to, but figured I would wait to chat with Polk on warranty first.
I do appreciate any input. Sorry for the long post, I try to be as thorough as possible.