lsim 705 fried crossover what kind of upgrades should I do.

I notice that one of my 705's was sounding a little off and crackly. after some investigation. I found the crossover has some burnt components. my question is i have this apart and it needs replaced. I need help on what upgrade I need to do. Polk want 200 for a new crossover. that's the easy fix. but if I can improve the crossover then that's the way I want to go. TIA
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Answers

  • pitdogg2
    pitdogg2 Posts: 25,498
    Looks like you had them at 11 for an extended period. Appears the resistor got rocket hot and may have emoliated the cap as well.
  • Clipdat
    Clipdat Posts: 12,937
    Must've been a hell of a NYE party!
  • VR3
    VR3 Posts: 28,697
    whatever you decide dont mount the resistor next to the cap...

    I thought Polk would have learned with the LSi... :-p
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • mhardy6647
    mhardy6647 Posts: 33,839
    edited January 2023
    Incidents like this just remind us of where all that power it takes to run modern loudspeakers goes :) Not to sound, but to heat. Yay. :#
    OK enough grumpy old man...

    On topic. it's kosher ;) to mount the power resistor offset from the board. Probably a good idea. Heat is the enemy.
    The other option is, of course, power resistors like this -- but, again, give 'em a little room to breathe.
    Many of these (like this Dale) are designed to be mounted on a heatsink.

    87ke9710cksj.png

    Outboard XOs aren't a bad idea, either. Let 'em respire!

    47715534881_04eb1d9cc4_b.jpg

    B)
  • mhardy6647
    mhardy6647 Posts: 33,839
    edited January 2023
    As a not-entirely-unrelated aside: I had a cathode bypass cap pop in my single-ended 2A3 amp due to its proximity to the cathode resistor. When I replaced the cap(s), I separated them from those power resistors.

    sej3qtvs2y3o.png