Alpine MRX-M100 No Sound From Amp

[freeman187]

Amp was working fine before building my new box. I removed my old box and sub from my truck and when I reinstalled it, the sub wasn’t getting any signal. I’ve tried switching RCAs and Power/Gnd cables. Fuses look good, internals look good, Redid the ground wire and still nothing. Light comes on and Power/Ground is at 12V. Any help would be great!

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[Louisiana_CRX 5,000+ posts]

Coul

Amp was working fine before building my new box. I removed my old box and sub from my truck and when I reinstalled it, the sub wasn’t getting any signal. I’ve tried switching RCAs and Power/Gnd cables. Fuses look good, internals look good, Redid the ground wire and still nothing. Light comes on and Power/Ground is at 12V. Any help would be great!

Is there anyway the speaker wires may of touched a grounded part of vehicle before the box was finished if so they may of shorted something internal on the amp ...the newer Alpine amps have a lot of build quality problems I read about a new bad Alpine amp on here usually once or twice a week .

 

[freeman187]

Nahh there’s no way

 

[02WS6]

Had a PDX-M6 drop rail voltage out to my sub melting the cone and snapping the coil. I'm not a fan of the newer Alpine amps.

If you've measured input voltage then, disconnect the sub, move your Multimeter over to VAC, play a song and check to see if you have any output voltage on the speaker connection. Adjust gain back and forth and see if anything is registered. If not then unfortunately an internal failure and you can either repair it (if you feel you have the skills for it) or replace it. From my experience its not worth repairing though due to more and more failures being reported on their amps in the last 5 years.

 

[freeman187]

Okay thanks for the info. And if it’s something internal then how exactly would I know to replace

 

[02WS6]

Okay thanks for the info. And if it’s something internal then how exactly would I know to replace

You would need enough electronics knowledge to know how to test the internal components. Its not something that can be taught over a forum. You could also look into repair shops in your area to see if its worth sending in for repair.