Help...no sound from speakers after Alpine HU installation!

[Jdg784 10+ year member]

Alright, finally got my new HU a 7894 and yanked out the old sony. Pretty easy install I figured, hook up all the speaker wires..etc..etc. It worked fine for about 30 seconds then the sound from the speakers cut off. It was right after I had pressed the media xpander button. Thinking I had just muted it or something I started playing around w/the filters and turned MX back off. But it still had no sound, throughout all of this the subwoofers worked. It's like there's no signal going to my speakers. Could my factory amp be screwing things ups? It's a 97' F-150 Lariat w.the "Premium Sound System".

Click to read more...

 

[Jdg784 10+ year member]

Also..I know the fuse/speakers aren't blown because when I went back out to the truck after about an hr of sitting and turned it on..it played for about 5 seconds then shut off.

 

[Randy Savage 5,000+ posts]

Originally posted by Jdg784 Alright, finally got my new HU a 7894 and yanked out the old sony. Pretty easy install I figured, hook up all the speaker wires..etc..etc. It worked fine for about 30 seconds then the sound from the speakers cut off. It was right after I had pressed the media xpander button. Thinking I had just muted it or something I started playing around w/the filters and turned MX back off. But it still had no sound, throughout all of this the subwoofers worked. It's like there's no signal going to my speakers. Could my factory amp be screwing things ups? It's a 97' F-150 Lariat w.the "Premium Sound System".

If you have a "premium sound system", you might have an internal amp, I had the same thing, and had to bypass the amp.

 

[Jdg784 10+ year member]

Oh I know there's an internal amp, JBL I believe...but it's not really worth the metal its made of..I guess I'll just have to go back and check my wiring tommorow.

 

[Jdg784 10+ year member]

Ahaha! got lucky, just so happened that the way I wired it all I had to do was unplug one plug and it worked!.

 

[Bumpin03 10+ year member]

you UNPLUGGED something and it started working??? hmmm....weird. i could understand if something came unplugged and you plugged itback in...but you had to unplug somethin? well whatever it doesnt matter, as long as it works

 

[Jdg784 10+ year member]

Well..yeah that is weird, ...it sounds great..I just can't get my subs working like they used to. I tried adjusting the crossovers, settings, and the gains..but no luck. THey're on..and working..just VERY quietly..........any ideas?

 

[Savant 10+ year member]

if something was plugged that shouldn't have been it could have been causing a short and internal fault trip.. time/temp resets it.. *shrug*

Not sure about the subs.. I'd say check the preamp outs and make sure you have tight connections.. make sure you have a good ground on the amp still.. play with the gains.. Also, see what the voltage is on the new preamps and see what you had on the old ones.. might not be giving enough juice to the amps as input signal.. worth a look...

 

[Jdg784 10+ year member]

if something was plugged that shouldn't have been it could have been causing a short and internal fault trip.. time/temp resets it.. *shrug*

Not sure about the subs.. I'd say check the preamp outs and make sure you have tight connections.. make sure you have a good ground on the amp still.. play with the gains.. Also, see what the voltage is on the new preamps and see what you had on the old ones.. might not be giving enough juice to the amps as input signal.. worth a look...

I think you're correct about the short. I'm positive it's not a lack of juice..I went from 1..maybe 2 volt on a good day pre-outs to 4v. They're all connected very well as well. I've gotta check the ground on the amp, that's about the only thing I didn't check.