|Ok so I hit a big F'n wave on the other day and the power for my HU popped out of it's new home on my biggest amp. Of course the whole system shut down. Yesterday I re-hooked it up and everything except my tower speakers is working. I can hear a light hum in them if I put my ear to them but nothing else. |
-The power light for the amp is on and it does not go into protection mode.
-I've tried moving the RCA's to another proven channel on the HU
-I've tried new RCA's on both front and rear channel
-There is a light pop in the speakers (tower) when the power to the amp is realized. This existed before the new problem as well and I know it's because of the gain settings. So it still does that.
I'm stumped short of something in the amp being TU that wouldn't effect the power/protection mode.
Amp is Boston Acoustic GT-28
Any thoughts? David, TM, MS, Phil or anyone who has an idea...Thanks in advance.
|Check your fader control in your head unit? If your yellow wire came undone, you might have lost your current settings, with the radio defaulting back to factory settings? |
The tower amp should not care that the head unit lost power; no different than simply turning the radio off...
|Thanks Phil I did that first should have put that in my bullet points. I did go back to factory settings but those are zero'd out. I've gone through all the settings and made sure they are correct as well. Still nothing. Is there a way to reset amps I am not aware of? I turned of the breaker to the whole system anything else?|
|Was this the amp that the H/U power came loose from? |
With a hum but no music, that just sounds like an RCA problem to me, but looks like you covered that, strange. Does that amp have internal fuses (mounted in the side) or one external inline? Probably unlikely, but make sure one fuse didnt pop. I'm fishing, i know!
|So is the culprit the amp or the headunit...is this what you are trying to figure out?|
|I'm lost... I agree with TigeMike Sounds like the amp is on, just not getting signal... |
|take a spare speaker and hook it to the tower amp to see if it getting signal|
The HU, depending on the make and model could have default settings (lowpass or dual zone) after a power loss. But since you've already reversed the front and rear RCAs and tested the amplifier with known working outputs, that would seem to eliminate the HU and point towards the amplifier.
The amplifier fuses should be multiple and exposed on the side.
Double check the remote turn-on lead inputs on the amplifier.
Reset the amplifier by lifting both the power and ground. Let the caps drain for a minute. Re-connect the ground first and power second.
To isolate and check the amplifier without pulling it for a bench check, use an iPod or other portable device directly into the amplifier. This may only require a 3.5mm to RCA adapter.
BTW, if your HU or amplifier loses ground while powered up, either may attempt to ground via the other through the RCA shields(even though RCAs are above ground). It's possible to fry the output or input RCA sections. So, have all power off as you are disconnecting or reconnecting things.
Alot of the above is thin but just being thorough before pulling the amplifier.
(Message edited by david_e_m on July 15, 2009)
|Thanks David those are great thoughts I'll try them all. I was seconds from throwing my back up amp in and decided to wait and see of there were a couple things I could try first. I like the iPod directly into the amp that should completely rule out the HU. I checked the fuses they were all intact. Checked the power turn on lead at the amp but I need to check it at the HU into the Bosche relay. |
One thing I pulled the RCA's out to eliminate the mild hum today while we were out and I noticed that the power light turned off. I then plugged them back in under load (stereo still on)and it went into "safe" mode then I turned the key off (thus the power to the amp) and back on and it was in "green" power mode. Kinda odd
Double check ALL grounds including the HU molex pins. Maybe DC on the RCA shields as a result of a poor ground?
|When we see amps turn off and on with RCA installation it is a bad amp ground 95% of the time. |
I agree with David, check ALL grounds...
|Oh that would be sweet!!! Thanks guys I bet the ground for the amp got jacked up at the distribution block hitting the wave so hard. I checked it at the amp itself but not there cuz it's in a bitch of a spot. I'll hunt it down. Thanks guys, I'll keep ya posted.|
|Thanks fellas that was it the ground had come free. I never knew an amp could use the rca's as a ground...threw me for a loop.|