Sub randomly stopped working

[csinclair]

My subwoofer has stopped working and will start again every once in a while. The amp powering the sub never shuts off, but the sub stops making noise. I thought this could be the RCA cable, so I tried hooking my phone up to the sub using a 3.5mm to RCA cable, and it worked fine. I figured it had to be the cable, so I replaced the RCA cable and it worked fine. Then it stopped again the next day. I tried again with the 3.5mm to RCA cable and it worked and continued to work after connecting it back to the receiver with the RCA, but stopped again a few hours later. Every time it stops, I can get it to work again by turning off my car, unplugging the RCA, connecting my phone with a 3.5mm to RCA, turning the car back on, playing music, then turning the car off and reconnecting the sub to the system. I have no idea why it does this and can't get the sub to keep working. It usually works for multiple hours before it stops. The last time this happened, the sub seemed to get weaker gradually before it cut out completely. Please help!

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[csinclair]

The sub cut out again while I was adjusting the gain on it. I tried hooking up my phone again and it worked fine after that. I don't know if this is just a coincidence or if it could have something to do with the gain knob. I'm pretty sure the issue is either with the RCA outputs on the receiver or with the amp. Are there any tests I could run to determine what the issue is? I don't have a DMM, but should probably pick one up cause that would make diagnosis much easier. Also, if this helps, it's a sub and amp combo that I got from my cousin, so I don't know the exact model number but it's a 12" Kenwood that I believe to be the KFC-W3012 based on the pictures I've found online and the amp is a MTX Terminator TNA251.

 

[csinclair]

Update: This time when the sub cut out I tried turning off my car, then I unplugged the rca cables, then I turned the car back on and played some music without the sub, then I turned it off again and hooked the sub back up and it worked. I had myself convinced I needed the 3.5mm to RCA cable to make it work, but I guess I just made that up. I'm gonna try hooking up my friend's sub to make sure the sub isn't the problem, but that won't be for about a week. I'm starting to think my receiver's RCA outputs are the problem, but it's a brand new receiver so I wouldn't have expected that. The receiver is a Sony WX-900bt if you're curious. Let me know if you guys have any thoughts!

 

[Boomin_tahoe 5,000+ posts]

Sometimes even new in the box electronics fail...for no given reason. If it's still under warranty, return/exchange for another. if they ask why, tell them.

Make sure the speaker wire to the s(s) hasn't come undone or is lose.

 

[csinclair]

Sometimes even new in the box electronics fail...for no given reason. If it's still under warranty, return/exchange for another. if they ask why, tell them.
Make sure the speaker wire to the s(s) hasn't come undone or is lose.

Yeah I've checked the speaker wire multiple times. Is there any way this could be an issue with the amp or should I just assume it's the receiver and send it in for warranty?

 

[crosjr 10+ year member]

Just leave your phone plugged into the RCA inputs on the amp for awhile. Longer than before it usually stops working from the head unit. That should let you know if it is the amp or something else, depending on the outcome. It could be any one of the pieces of equipment at this point until you narrow it down.

 

[csinclair]

Thanks for the reply. It hasn't cut out in about a day and a half and I've driven the car quite a bit. I'll wait until it cuts out again and then leave the RCA cable for my phone plugged in for a few days and see if anything happens. Should I leave a phone plugged into it at all times, or just leave the cable plugged into the sub and hook up my phone when I test to see if it cuts out?

 

[csinclair]

After almost four days now my sub is still working fine, so I had another thought and was wondering if anyone might know anything about it. I realized that every time the sub has stopped working it has been within about a day of when I used the mega bass button on my receiver. This button is just supposed to enhance the lower frequencies, so I figured it just raised the lower frequencies by a few DBs in the EQ, but is there any way this could lead to the bass cutting out after a day or so? Or could it somehow be sending too much to my amp and causing a problem there somehow? I don't know if this could even have anything to do with the problem, but it's just a pattern I noticed. Let me know if you have any thoughts on it

 

[Boomin_tahoe 5,000+ posts]

It shouldn't, but in your situation, it might.