So i had the pico fuse problem on my 7800mp for quite some time. I never knew what it was so i let it be for almost 2 months. It caused the obvious "engine" and other horrible noises and it would also cause my amp to cut out at high volumes on low notes. First i just wrapped all the rca's with wire and grounded them to the headunit and that worked great it sounded like i had a new amp and subs, no more noise and the amp no longer cut out no matter how hard i pushed it. Then 2 days later a cap on my amp went. In between the time of getting a new amp i ripped the unit apart and soldered over the pico fuse and all the horrible noises coming from my subs were gone. Im using a different amp now and theres no noise coming from my subs but the amp is still cutting out on the really low notes at high volumes.. Im not sure if this is because im pushing the amp to hard or what. The subs this amp is pushing can handle 2 of these amps RMS. So im wondering if the headunit is still causing a problem. Any thoughts? I really dont want to have all that nasty wire wrapped around my rca's again. Yes my ground and power wires are tight and solid!
i have the same head and fixed mine by soldering wire to the rcas. i dont have enough confidence to solder onto the board. what kind of voltage do you have going to your amp? too low and it will shut down. could be a heat issue also.
Was/Is this problem specific to your model, or are all Pioneers at risk of this? Has Pioneer addressed this at all?
The main problem is/was theirs a small fuse inside the headunit named a "pico" fuse. In some way this fuse is apparently inline with the ground for all the RCA outputs. If you "hot swap" the rca's ( take out and plug in) the rca's while the unit is on, theirs a big chance you've damaged your pico fuse inside your pioneer unit. I dont know if EVERY model is at risk for this but i know a huge amount are. If it happens to your unit within the warranty period they will replace it. If not, your on your own. If you let the problem go unresolved long enough you also risk ruining your amp that the RCA"s are connected to because the ground can die completely inside the headunit resulting in the rca's going to your amp for a ground and from what i read, thats not to healthy for your amp. Pioneer may have addressed this problem on newer models but im not completely sure. Ive narrowed my problem down to pushing the amp to hard. Like i said before my subs can handle the RMS of 2 of these amps and i basically have this one pushing out all it can rite now resulting it to either go into protect or cut out for short periods of time. Its not suppose to cut completely out, theres some type of circuitry in this amp that is suppose to just lower the volume of the amp and increase once it cools back down, but it just cuts out for about 2 seconds, comes back on at low level and returns to full volume after a few seconds.
I would replace them with a PC mount resister, any super small value will work By floating the RCA ground slightly above chassis ground, noise problems would go away
can you explain this some more? i seem to be picking up a little more noise now that i had to swap amps. funny thing is this amp never made noise before. i had to lengthen my rca's going to my 4ch and one got pinched in the back seat after i put it back up from moving some boxes for a friend. id hate to have to replace a perfectly good head unit. i was even considering looking into a nice 4ch line out converter for my front and rear outs. the sub out is fine. or even a balanced line transmitter/receiver. im even thinking of moving my rca's to the middle of the truck. or maybe my speaker wire is picking up noise from the power wire its crossing over? either way its time for a change anyways.
I hate pioneer just not for the pico fuse but for other things. My recommendation get rid of it get a alpine or kenwood and be done.
There is no one solution for noise in a sound system, so with that in mind lets see if I can explain this without messing up. In order to minimize noise in car sound systems, manufactures decided that the audio ground and the power ground needs to be seperate. So they float the audio ground slightly above power ground. And in most cases it works. A ground loop occurs when different potentials (resistance) exist. In other words there are more than one path to ground. And in some cases, the audio shield might also be considered a power path to ground. We have noise I get carried away when it comes to noise elimination in my car. First, the battery negative post is tied to the truck body with a 4 ga wire. Then at this same point, an 8 gauge wire goes back to the amp grounding point. This wire and the amp ground are about 1/2-inch from each other and bolted to the body under the seat. The radio is next. The power ground (the black wire in the radios plug) is hooked to the radio chassis along with a 12gauge wire. This wire is also routed to the same grounding point under the seat. One other wire, a 14ga from the chassis of the radio to the chassis of the amp (any amp should work). Is this overkill, yes it is, but even when I had 4 amps in my truck, there was no unwanted noise. http://www.caraudiotalk.com/audio-forum/showthread.php?t=3254 The resistance to ground for every component is the same. No Noise. When the audio ground resistance is less than the power ground, power will travel along that path and we have noise. My method is overkill but it has worked for me. Ground loop isolaters also work, but they use transformers to isolate the audio path. And transformers are NOT linear devices. There will be signal loss. And in most cases the difference is huge.
