Question about Legacy Audio LA720 Car Audio Amplifier

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Crazy Car Amplifier

I have a JENSEN JXP460, not the best car amplifier but it USED to work. I was driving to Boston one night and had the music on, high but not MAX and the the Sub shut off and kept making single thud noises which I noticed went with the amplifiers blinking power light.

when plugged in it is red then turns green quickly, but goes right back to red

I unwired everything changed the ground checked all connections and only hooked up the power, ground ,and remote wire. It does the same thing. I used my multimeter and measured 12V at the power and about 11V at the remote so it is receiving the power.

I did a little homework online and read that the problem my be a blown transistor. Without any power hooked up I checked out the transistors.

I found 0 OHM Resistance checking MOSPEC F12C20C ANA and MOSPEC F12C20C 1A side by side. Of the 3 terminals of each transistor if I measure the outside two of either I will get 0 Ohms. Am I getting at anything here? What is my next step?

Thanks for any help out there guys.


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  • tosims7 Nov 03, 2008

    Wow that was such good advice man I never thought of that!
    think you should be posting on

    To anyone else I enjoy the challenge I am looking to fix this, or at least give it a shot.



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To be honest with you, your best bet is to buy a new amp.  cheap amps are cheap because they plan on you buying another one when they don't last.  save up and buy a nice amp, thats my advice.  if you really want to fix this one i wish you luck, but i've never worked on an amp before, just install and troubleshooting, so in my experience this one's fried.  But i'm sure it could be fixed, the question is wether or not it is worth it?

Posted on Oct 30, 2008


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