KMHPaladin

I've been having some bizarre problems with my aftermarket head unit. About a month ago it would intermittently not output sound, though the head unit would stay on. I thought it was a loose audio connection, so I took the player out and checked every connection.

Well, when putting it back in I think I crunched a wire or something. Believe it or not the head unit would only come on when the headlight switch was in the middle or on position. I knew it wasn't getting any power with the headlights off because the LCD color settings (you can see the screen below, it's adjustable by RGB levels) would be wiped out.

That was confounding. I yanked it out again, undid all the connections and redid all the wires, and replaced it. Great, it didn't work at all. I replaced the original Delta head unit just to see if my Panasonic was broken, and it would light up the buttons when I switched the lights on, but not power on.

So, I surmised, maybe the switched power wire got clipped. I ran a wire from the 75x post to the accessory wire going to the head unit and plugged everything back together. Still no dice. I finally decided to check the fuse box and, yup, the fuse for the radio was blown. Radio now turns on.

Okay you're saying, great, now it works. Well, yeah. But, when I turn the car off, I think the amplifier is still turned on. I hear a very light hissing noise out of the front speakers even with the car switched off. When the interior lights dim out (i.e. open and close the door) there is a weird distorted noise that comes out of the speakers too.

Any ideas? I'm confounded.

<img src="http://www.bestpriceaudiovideo.com/multimedia/images/cqhx2083ubig.JPG">

de (-eeez_nutz)

You can always run a new relay or wire from your car's fusebox to your amp turn-on wire.

RKA

Isn't there a light or something on the amp indicating whether it's running or not?

Next, I would use a multimeter, and test the remote turn on lead to see if it's properly signaling the amp to turn on and shut off properly. At least that will point you to the wiring, or the amp as a likely culprit.

KMHPaladin

They're definitely on even with the key removed, when the head unit turns off. I didn't check the amp itself because I was mulling over possible problems on the drive back before it occurred to me that the amp wasn't turning off. Does the remote turn on lead also send a signal to turn the amp off? I was thinking the remote lead was possibly the problem, but wasn't sure if the amp was just supposed to power off when the key was removed and power cut or if it got constant power.

KMHPaladin

That sounds like a strong possibility. Any idea what might have popped the fuse? I <a href="https://forums.audiworld.com/a4/msgs/2231060.phtml">blew a Basslink</a> a few months ago. The fuse would pop whenever I replaced it and the general consensus was that the integrated amp went bad. I figured it was just crappy luck with an Ebay purchase, but this kind of worries me now. The Basslink was powered directly from the battery through a fuse (which only popped once, when I think I momentarily grounded the power wire removing the Basslink months before the problem) and grounded on one of the tie-down clips. It got audio through the rear deck speakers.

I presume I couldn't run direct switched power to the turn-on wire, since my understanding is that it's very low power. The relay would cut it down to size?

de (-eeez_nutz)

...fuse the internal relay into the closed position, which would keep your amp on all the time.

I've always found it odd that the radio mfg-ers never put a fuse on that amp turn-on wire. They probably count on that internal relay to isolate everything.

de

KMHPaladin

Appreciate your and Raj's input. I think you guys have it pretty well nailed. Now to find the appropriate relay!

Do you recommend using the fuse box, 75x post, or something else switched? I have my radar detector hardwired to the rear wiper fuse right now. It also seems not to want to turn on, but it turns on fine with the cigarette lighter power. However, the fuse appears to be intact (single filament) and I think I just broke something on the remote. I removed the cover from the remote so I could fit it behind one of the dashboard buttons, so it's just a naked circuit board. I think I must've broken something on the board.

de (-eeez_nutz)

If you do tap into the fuse box, keep in mind that your amp will be on with your car, even though the radio may be off. Shouldn't be that big of a deal, although, if you can hear something now, in your current state, you're amp might be getting some signal noise.

When you go to turn on the radio, (depending if your amp has soft turn-on or not) you might get an initial thump sound. That's the sound of your radio turning on, only it's being amplified. It can get irritating after a while.

de

de (-eeez_nutz)

Just get a SPDT relay. I'm just going by memory here but I think pins 85 and 86 are for the relay coil (one goes to ground, the other goes to switched power in the fuse box), 30 would go to constant +12v constant, 87a is normally closed, so you wouldn't use it, and 87 would go to the amp turn on wire.

KMHPaladin

I found <a href="http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CT LG%5F011%5F002%5F013%5F000&product%5Fid=275%2D241" >this</a> 12VDC, 1 amp relay. I think the remote turnon only needs 1 amp, nothing big. I can see that the relay would need ground, the power input that is being relayed, and an output, but why would it need a constant power input?