CDR-220 Trouble, external amp / antenna
04-06-2009, 05:57 PM
#1
Three Wheelin'
Thread Starter
CDR-220 Trouble, external amp / antenna
Hey folks,
I installed a CDR-220 head unit from SW Stereo over the summer. I just added an Alpine MRP-F240 Amp (40Wx4 rms) under the passenger seat.
What I've found is that the remote amp lead line is giving a constant 0.6 volts, even with the stereo and car off. It's enough power to turn the amp "slightly" on it seems - the blue LED light on the amp glows faintly just from that small signal. It's enough to run down the battery over a few days of not driving.
I also discovered that the antenna amplifier remote turn-on lead is giving a constant 0.6V too. When I switch the car off I can hear a faint hum under the dash behind the climate control. Maybe this is where the antenna amp is located? If not, where the heck is it located?
Additionally, the wiring harness that I was sent had the ground wire for the stereo misplaced in the harness - it was stuck in the "illumination" pin instead of the "ground" pin! So I was somehow grounding the head unit through its "illumination" circuit. I corrected this, but am still getting the same constant 0.6V on those two remote turn-on lines.
I tested the constant +12V, switched +12v, and ground, and they all have solid numbers (good voltage and little/no resistance).
Ideas so far? Has anyone else had trouble adding an external amp with the cdr-220? SW Stereo made up the harness for the new amp. It has four coax/rca connections and a single remote amp turn-on wire.
The sound quality seems just fine with the new amp. With the old amp I would get a light "pop" sound everytime the PDAS hydraulic pump kicked in pressure while driving. The new amp is running fine with no noise.
Cheers!
nick
'91 C4 Cab
I installed a CDR-220 head unit from SW Stereo over the summer. I just added an Alpine MRP-F240 Amp (40Wx4 rms) under the passenger seat.
What I've found is that the remote amp lead line is giving a constant 0.6 volts, even with the stereo and car off. It's enough power to turn the amp "slightly" on it seems - the blue LED light on the amp glows faintly just from that small signal. It's enough to run down the battery over a few days of not driving.
I also discovered that the antenna amplifier remote turn-on lead is giving a constant 0.6V too. When I switch the car off I can hear a faint hum under the dash behind the climate control. Maybe this is where the antenna amp is located? If not, where the heck is it located?
Additionally, the wiring harness that I was sent had the ground wire for the stereo misplaced in the harness - it was stuck in the "illumination" pin instead of the "ground" pin! So I was somehow grounding the head unit through its "illumination" circuit. I corrected this, but am still getting the same constant 0.6V on those two remote turn-on lines.
I tested the constant +12V, switched +12v, and ground, and they all have solid numbers (good voltage and little/no resistance).
Ideas so far? Has anyone else had trouble adding an external amp with the cdr-220? SW Stereo made up the harness for the new amp. It has four coax/rca connections and a single remote amp turn-on wire.
The sound quality seems just fine with the new amp. With the old amp I would get a light "pop" sound everytime the PDAS hydraulic pump kicked in pressure while driving. The new amp is running fine with no noise.
Cheers!
nick
'91 C4 Cab
04-06-2009, 07:37 PM
#2
Rennlist Member
old amp makes pop
if the old amp is the factory one its the ground in the harness that creates the pop. groung right there at the seat and the pop goes away. fixed my problem was driving me crazy. actually it was a fix per porsche. I did not cut the harness to do this.
04-06-2009, 07:57 PM
#3
Burgled
Rennlist Member
Rennlist Member
the hum behind the CCU is the air sample/cooling fan. If it is working correctly it will run 15-20 minutes after the car is shut off.
04-06-2009, 08:13 PM
#4
Three Wheelin'
Thread Starter
Ah, thanks for that jimq! That clears one mystery.
Dutch - I've grounded the new amp with the same stock +/- cables. I ran a multimeter on the ground and the resistance barely registered between that ground and a chassis bolt. Even still, I should use a short ground wire regardless. Not sure what I was thinking on that, but I'll correct it this weekend.
*Edit - heard back from SW and they're thinking an issue in the head unit. Going to send it back for the pro diagnosis. Glad I posted this, at least for the tips above!
Dutch - I've grounded the new amp with the same stock +/- cables. I ran a multimeter on the ground and the resistance barely registered between that ground and a chassis bolt. Even still, I should use a short ground wire regardless. Not sure what I was thinking on that, but I'll correct it this weekend.
*Edit - heard back from SW and they're thinking an issue in the head unit. Going to send it back for the pro diagnosis. Glad I posted this, at least for the tips above!
04-06-2009, 10:33 PM
#5
Rennlist Member
I installed a CDR-220 last year too. I love the unit. But, the factory amp isn't doing it for me either. Did you run power from the battery or use the factory power from the wiring harness?
I would like to install a different amp, but I have some many other things to do I don't want to spend the time running power for an amp at the moment. Thanks for any help.
I would like to install a different amp, but I have some many other things to do I don't want to spend the time running power for an amp at the moment. Thanks for any help.
