I recently purchased and installed a Pioneer DEH-P860MP and it was working great. I then shifted it around a bit, and now there is some major static coming through the RCA outputs, I hear this is common and is related to some type of grounding problem? What can be done to fix it? There is no noise from the head unit's internal amp...
There is a bare power wire somewhere if the shield ground has burned. That needs to be repaired before you do anything else.
To check the shield ground, disconnect all RCAs from the head unit. Set you meter to ohms. Touch the black lead to the case of the head unit. Touch the red lead to the shield of the RCA output jacks on the head unit. You should get a reading near zero ohms.
If the shield ground is burned and the HU is under warranty, see if they'll repair it under warranty.
To check the shield ground, disconnect all RCAs from the head unit. Set you meter to ohms. Touch the black lead to the case of the head unit. Touch the red lead to the shield of the RCA output jacks on the head unit. You should get a reading near zero ohms.
If the shield ground is burned and the HU is under warranty, see if they'll repair it under warranty.
Should the head unit be on or off when I'm testing it?
I'm pretty sure I did burn out the shield ground...exactly what is it? The head unit isn't under warranty...
I'm pretty sure I did burn out the shield ground...exactly what is it? The head unit isn't under warranty...
It doesn't matter whether the head unit is on or off so you should do it when it's off.
You burned the ground by allowing a 12 volt power source to contact a ground circuit that was not capable of handling as much current as the fuse in the 12 volt power line.
The least invasive repair is to use external jumpers. Since the internal fusing (either a trace or a surface mount fuse) is no longer available to limit current if this should happen again, I suggest you fuse the jumper wires. The small 5mmx20mm fuses and holders available from radio shack will suffice. A 1 amp fuse in each will offer good protection and will not blow under normal operating conditions.
The attached photo and the one in the next post show the connections. You solder one end of the fuse holder to the RCA cable shield ground. The other end of the fuse gets connected to the head unit chassis.
You burned the ground by allowing a 12 volt power source to contact a ground circuit that was not capable of handling as much current as the fuse in the 12 volt power line.
The least invasive repair is to use external jumpers. Since the internal fusing (either a trace or a surface mount fuse) is no longer available to limit current if this should happen again, I suggest you fuse the jumper wires. The small 5mmx20mm fuses and holders available from radio shack will suffice. A 1 amp fuse in each will offer good protection and will not blow under normal operating conditions.
The attached photo and the one in the next post show the connections. You solder one end of the fuse holder to the RCA cable shield ground. The other end of the fuse gets connected to the head unit chassis.
Attachments
Same Problem
Dear Perry,
I have the same problem with a P88RS. I disassembled it and I can see an SMD fuse next to the RCA Ground. Do you think this FUSE can be the source of the problem? What is the type of this fuse ususally? 1 OHM can be enough?
Thanks in advance,
Vanquish
Dear Perry,
I have the same problem with a P88RS. I disassembled it and I can see an SMD fuse next to the RCA Ground. Do you think this FUSE can be the source of the problem? What is the type of this fuse ususally? 1 OHM can be enough?
Thanks in advance,
Vanquish
Does it have a number or letter on it?
Have you measured the resistance across it (with the head unit completely disconnected from power source and amplifiers)?
Have you measured the resistance across it (with the head unit completely disconnected from power source and amplifiers)?
Perry Babin said:
Dear Perry,
I can read the follows above the fuse: FU351, and there is a "P" letter on the fuse itself. I'm almost sure that this fuse can be the problem, this is the only connection between the house ground and the RCA ground, if I measure it shows unlimited resistance. I will try to replace it, the only question is the type of the fuse, what do you think? 1 Amp is ok?
http://www.littelfuse.com/data/en/Data_Sheets/466.pdf
This datasheet should apply to that fuse. P = 3A.
It should read very near 0 ohms. If it measures higher than 1 ohm, it's defective.
This datasheet should apply to that fuse. P = 3A.
It should read very near 0 ohms. If it measures higher than 1 ohm, it's defective.
Im not sure if my situation is the same as his but i have been using deh-p6500 for many years and it never happen to me before. The other day I install the aux port (ip-bus) to my ipod using RCA. After a few mins, i get an annoying, loud static noise. I switch over to radio and cd player, and i still get that noise. If i turn off the headunit for a few minutes, and turn on again, it doesn't make that noise until 5-10mins later. When i took out my headunit, the back was very hot.. and i try to check it out what making the noise and didn't find anything missing or loose wires.
Could be i have the same problem and i should do the same exact thing??
Could be i have the same problem and i should do the same exact thing??
With most systems, an open shield on the head unit (or on any signal processor in the signal line) will cause significant noise. If the noise is minor, you may be able to reduce it to acceptable levels by reducing the gain on the amp.
Hey, great work, just happened to mine, need to repair then will do what you have posted here, do i have to do that with all rca cables?
You can generally ground only one to restore the shield ground for all of the RCA outputs. If one or more of the ungrounded channels produces noise, ground them also.
The sensitive ground issue is well-known on certain Pioneer head units. See this thread:
http://www.diymobileaudio.com/forum/showthread.php?t=13889&highlight=880prs+grounding
at the diymobileaudio forums for info. It's a very long discussion, but the answers are all there. In a nutshell, there is a TINY fuse or sacrificial resistor that burns out if the grounding is not handled carefully.
To prevent problems, DO NOT connect/disconnect any RCAs to anything if the unit is on. In fact, disconnect the 'phantom' power as well. When it comes to installation and such, the first thing to attach is the ground, and the last thing to disconnect is the ground.
It was also recommended to ground the chassis to the same point as the harness ground.
http://www.diymobileaudio.com/forum/showthread.php?t=13889&highlight=880prs+grounding
at the diymobileaudio forums for info. It's a very long discussion, but the answers are all there. In a nutshell, there is a TINY fuse or sacrificial resistor that burns out if the grounding is not handled carefully.
To prevent problems, DO NOT connect/disconnect any RCAs to anything if the unit is on. In fact, disconnect the 'phantom' power as well. When it comes to installation and such, the first thing to attach is the ground, and the last thing to disconnect is the ground.
It was also recommended to ground the chassis to the same point as the harness ground.
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