Sony Head Unit Problem

(raider40) · (raider40) **Join Date: Oct 2001** 03-29-2005, 8:03 PM

In trying to get my new sub and NVS speakers tuned I've run across a problem and I'm out of ideas.

I've got a Sony CDX-MP70 head unit which is powering a PPI 4125 (running the 808s), a JL 500/1 (running the Type-R sub) and the 4 MB Quart RCE116s are wired directly to the head unit.

I got everything wired up and when I went to tune the amp gains the head unit started clipping (shutting off momentarily) when the volume got above 1/2 way.

I have 2 Optima Yellow Tops (wired thru a Perko) that I've had for 4+ years and were run dead over the winter. Thinking it was the batteries, I tried charging them (they wouldn't hold at all), so today a broke down and bought 2 new Blue Tops.

I got them home, hooked them up and the same thing happened only this time the only time the H/U cut out was when the CD player was running - when the tuner or Aux (my iPod) were running I had no problem.

I disconnected both amps to see if it was something in their wiring but the problem persisted with only the boats wired to the H/U. Last season the boat speakers were wired to the 4125 and that is the only thing I've changed. I've checked all the speaker wiring to ensure it's correct (it is).

HELP! I'm out of ideas and need to get this lined out so I can hit the water w/ music.

(chas) · (chas) **Join Date: Feb 2002** 03-29-2005, 8:13 PM

Make sure you have a solid ground to the head unit. My Alpine did the same thing over time (radio was fine, cd would cut out) the tuner draws less current than the cd drive thus making the unit pull more draw when in cd mode. I ended up grounding the head unit to the battery. Hope this helps.

(biz) · (biz) **Join Date: Mar 2004** 03-30-2005, 7:13 AM

And, you can get a "cleaner" more relieable 12+ volt source from the battery. I had the same problem... it ended up being the HU. It wasn't getting enough power and would cut in and out at high volume. I ran a couple of relays for both the switched and constant power and no Problems now.

(jklein) · (jklein) **Join Date: May 2001** 03-30-2005, 9:38 AM

Put two grounds on the HU. The one from the main wiring harness, and run a separate ground directly from the minus terminal on your main battery to the HU chassis.

It's my understanding that alot of HU's actually ground through the antenna lead. Well, since that's not mounted to ground in a boat, you can get a bad ground. Run the extra and you'll be golden.

(monstertower) · (monstertower) **Join Date: Mar 2003** 03-30-2005, 7:41 PM

That's impressive and quick replies sharing "been there - done that" advice. I would have recommended a bigger hammer

And how was it we solved these problems before Al Gore invented the internet?

(Message edited by MonsterTower on March 30, 2005)