LSi9 crossover available?

tripleguy

Speakers were overdriven. No sound, just a buzzing noise. Voice coils on spkr #1 woofers are toast as cone rubs. Spkr #2 mounting standoffs are cracked at spkr plug base. Corners of board are cracked off. I suspect a trace or 2 are broken. Woofers and tweet test fine. Resistors also test fine. Thoughts on repairing this mess? Not mine - a friends. Thx

pitdogg2

Is "overdriven" the new word for dropped to the floor?
I cannot see how abusive volume control could do that.

tripleguy

No physical signs of damage to the cabinet. I see no other reason the speaker in question is not passing sound.

F1nut

Overdriving speakers does not cause boards to break.

Look on eBay for someone parting out a pair. Polk doesn't have those crossovers or drivers.

tripleguy

I may have to try to repair the board. Have schematic and I'll see if I can find areas where trace is broken near components or wires. I see a couple suspect areas. I've seen drivers on eBay.

I know what you're saying. He's a friend and has no reason to fib. He has 10 pair of these and had this pair hooked up in his large shop. He had it cranked for quite some time while working in there and said sound quit. Just gets a buzzing now. I can't see any indication of a drop. Strange. No marks that I could see on any screws indicating they'd been opened.

Hansvelton

F1nut wrote: »

Overdriving speakers does not cause boards to break.

Look on eBay for someone parting out a pair. Polk doesn't have those crossovers or drivers.

Exactly!!

Hansvelton

tripleguy wrote: »

I may have to try to repair the board. Have schematic and I'll see if I can find areas where trace is broken near components or wires. I see a couple suspect areas. I've seen drivers on eBay.

I know what you're saying. He's a friend and has no reason to fib. He has 10 pair of these and had this pair hooked up in his large shop. He had it cranked for quite some time while working in there and said sound quit. Just gets a buzzing now. I can't see any indication of a drop. Strange. No marks that I could see on any screws indicating they'd been opened.

Hmmm. Just what F1 says, overdriving could not do this. That has to be physical damage, maybe from the past. But I have seen when they are dropped straight down the boards can split from the terminal board, from the weight of the inductors. As to not seeing damage, not sure.

tripleguy

The cement resistors and drivers all test fine in this spkr. Anything else to check as to why they're not passing sound? The mate to this one has the woofer VCs rubbing so those are shot. I don't yet have that spkr to test resistors or tweeter.

Hansvelton

tripleguy wrote: »

No physical signs of damage to the cabinet. I see no other reason the speaker in question is not passing sound.

Were all 4 screws in place that hold the crossover board to the stand offs?

tripleguy

Yes. All 4 screws present on board and yes, jumpers in place on binding posts.

tripleguy

Hansvelton wrote: »

tripleguy wrote: »

No physical signs of damage to the cabinet. I see no other reason the speaker in question is not passing sound.

Were all 4 screws in place that hold the crossover board to the stand offs?

I should clarify this. The 2 bottom standoff posts were briken off. One of them had a corner of the board still screwed to it. The other 2 posts weren't sheared off but one had a corner of the board cracked off and still screwed to it. So 2 posts sheared off and 2 board corners cracked and busted odd. One trace appears to have cracked. I'll repair that and see how it goes.

SeleniumFalcon

When I worked for Polk I would test owner's crossovers for them, I would send pink noise into an amplifier (Dynaco ST70) with an 8 ohm load on the crossover's tweeter/midrange outputs and look at the output on a spectrum analyzer. This would show the crossover's frequency response for each required output. I can probably put the same test together and check out yours at no charge.

tripleguy

Thx!! I'm going to try repairing the board 1st. It's cracked in the corner right where the L2 inductor meets the D2 pos lead. I'll try and jumper this as the board is cracked at L2 and the pad is lifted. If that works, then I'll get some used drivers for the other spkr as the board is intact.

dromunds

SeleniumFalcon wrote: »

When I worked for Polk I would test owner's crossovers for them, I would send pink noise into an amplifier (Dynaco ST70) with an 8 ohm load on the crossover's tweeter/midrange outputs and look at the output on a spectrum analyzer. This would show the crossover's frequency response for each required output. I can probably put the same test together and check out yours at no charge.

That was an awesome gesture!

tripleguy

Speaker with the cracked board is fixed. I was able to jumper the lifted pad and cracked trace on inductor L2 to the D2 Pos speaker lead and all seems well with that one. Hopefully the other one just needs new drivers. Are they both the same or is the upper one just a bit different than the bottom?

F1nut

The drivers are marked.

tripleguy

Thx. Yea, they are marked 1 & 2 for schematic purposes. Otherwise identical. I'll have to watxh eBay and hope I get good ones. Always a crap shoot.