Does anyone have a schematic for this HU? I have a lot of noise coming through my speakers when the HU is on. I first encountered this issue last year from removing RCA's without disconnecting battery first. There was a pop and that's when the noise officially started. I believe this also lead to my amp being damaged which I have since repaired with Perry's help here. Thanks again Perry!
Anyways, this unit has 6 RCA outputs so it seems a little tedious to wire each one to the case ground and want to possibly replace the fuse inside the unit instead. At the time, I searched around and found the "quick fix" of wrapping wire around the RCA shields. This eliminated the noise for a while but it started quietly coming back in the last few weeks. The strange thing is that once I repaired my defective amp, I hooked it back up and the noise came through as loud as it originally did when it was first damaged last year.
It sounds like the amp is probably the issue but knowing that the "quick fix" on the HU worked at first leads me to at least think that fuse inside the HU needs to be repaired anyways. By the way, the amp required a swap of an op-amp TL072 connected to the RCA input so maybe it was a cheap part and doesn't eliminate noise?
I appreciate any help, thanks!
Anyways, this unit has 6 RCA outputs so it seems a little tedious to wire each one to the case ground and want to possibly replace the fuse inside the unit instead. At the time, I searched around and found the "quick fix" of wrapping wire around the RCA shields. This eliminated the noise for a while but it started quietly coming back in the last few weeks. The strange thing is that once I repaired my defective amp, I hooked it back up and the noise came through as loud as it originally did when it was first damaged last year.
It sounds like the amp is probably the issue but knowing that the "quick fix" on the HU worked at first leads me to at least think that fuse inside the HU needs to be repaired anyways. By the way, the amp required a swap of an op-amp TL072 connected to the RCA input so maybe it was a cheap part and doesn't eliminate noise?
I appreciate any help, thanks!
Here is the link to my amp thread as well...
http://www.diyaudio.com/forums/car-audio/243430-rf-6001-bd-no-audio-output.html
http://www.diyaudio.com/forums/car-audio/243430-rf-6001-bd-no-audio-output.html
I took it apart last year and checked RCA shield to chassis ground and there was no continuity. I found that quick fix to ground with wire and then it checked good. Was just assuming that the fuse was blown from what I read at the time. I'm gonna take it out and check it hopefully tomorrow. Thanks for the part number. Hoping this fuse will mute all the noise if thats the problem.
It's done to protect against electrical fires. Under normal operating conditions, there will NEVER be anything near the 3 amps that the fuse is rated for. The fuse blows when a 12v source contacts the RCA shields. This generally happens when someone pulls an amp and the RCAs are sliding around in the trunk and eventually contact the B+ wiring. It can also happen if a transformer shorts from the primary to the secondary in the amplifier.
If you've been in the car audio business for long enough, you'll find RCA cables that have melted into the OEM wiring, interior panels, carpet and seats from the trunk to under the dash. This cannot happen with the fuse in the shield circuit. That's why I recommend inserting fuses when jumpers are connecting externally as a temporary repair.
RCA Shield Repair
If you've been in the car audio business for long enough, you'll find RCA cables that have melted into the OEM wiring, interior panels, carpet and seats from the trunk to under the dash. This cannot happen with the fuse in the shield circuit. That's why I recommend inserting fuses when jumpers are connecting externally as a temporary repair.
RCA Shield Repair
OK so I got the radio out today and confirmed no continuity between the RCA shields and the case ground. I checked the p fuse and also read open on the meter.
I still have the wire wrapped around the RCA shields and with my newly repaired amp removed (no signal input), just about all noise is eliminated. There is a slight noise heard but it is pretty quiet. Once I connect amp back up (signal input) the louder noise returns. So sounds like my amp is bringing the noise into the equation.
I don't think it is the RCA wires being close to the power wires in the back of my truck as they are in same position from older amp with no previous noise. I'm wondering if it's just from the op-amp I put in to fix my amplifier.
I still have the wire wrapped around the RCA shields and with my newly repaired amp removed (no signal input), just about all noise is eliminated. There is a slight noise heard but it is pretty quiet. Once I connect amp back up (signal input) the louder noise returns. So sounds like my amp is bringing the noise into the equation.
I don't think it is the RCA wires being close to the power wires in the back of my truck as they are in same position from older amp with no previous noise. I'm wondering if it's just from the op-amp I put in to fix my amplifier.
I just ground the RCA input jack with some wire to ground terminal to see if this would help. The noise did not go away and I had some "popping" while changing source modes on HU. Then on CD mode (so i had signal playing) with volume on zero, had some rumbling coming through sub. Not much but seemed like stray voltage trying to come through. Could this be a short somewhere in the amp. Removed "ground" from RCA and hooked back up and everything works fine, besides the original noise returning.
The amp is likely OK if you didn't see any spikes on the RCAs. That means that the contact to 12v was almost certainly at the head unit or at the other end of the RCAs.
The jumper has to be at the head unit. If you ground at the amp end of the RCAs, you'll get lots of engine noise (and other noises).
The jumper has to be at the head unit. If you ground at the amp end of the RCAs, you'll get lots of engine noise (and other noises).
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