Engine whine and ground loop fixes... take two

[dman4486 5,000+ posts]

I have opened up my DEH-P5900iB headunit, but am unable to locate even a single fuse... I cannot find any tags labeled with FU-???I am lost, I would be able to fix this headunit if only I knew where the dang fuse was... any help on this model would be appreciated

take some pics and then we can help

 

[southbark33]

Ok, i bought the service manual for $10 online, I found the fuse, it's on the underside of the circuit board... go figure. Wasn't incredibly hard to disassemble the entire thing, just tedious.

Well, I soldered on a 1-ohm 1/4 watt resistor in place of the pico-fuse, hooked the HU back up in my car and still recieved the god awful engine whine...

I'm almost positive I took off the correct fuse... it had a little "p" on it and was labeled FU-352.

Is it because I used a wrong type of resistor? it seems like it should be fine...

I'm opening it back up right now, I'll take some pictures and upload them.

 

[southbark33]

pics of the back side of the motherboard, with a 1ohm 1/4 watt resistor soldered onto where the fuse used to be.

Still receiving awful noise.

I have the RCA cables grounded right now instead, because the RCA grounding works well as a temp fix. It reduces the noise by about 90%, but I'm really just not satisfied... I want that fuse fixed for good, but the resistor isn't doing a ****ed thing. Any help/comments would be helpful

Thanks guys

Pics:

http://i35.photobucket.com/albums/d172/southbark33/IMG_1988.jpg

http://i35.photobucket.com/albums/d172/southbark33/IMG_1989.jpg

http://i35.photobucket.com/albums/d172/southbark33/IMG_1994.jpg

I also have the service manual if anyone wants a look at it for the DEH-P5900iB model

If it'll help you diagnose my problem then I'm more than happy to share it, hit me with a pm

 

[canadapettit 10+ year member]

Well i could tell you a way that you could check to see if the fuse is any good,but now that you replaced the pioneer fuse with resistor it won't work. My guess is that the fuse is still good since you were getting signal to the amp. If that fuse was blown, you would get no sound. My only suggestion is to check all of your grounds and make sure that they are good.

EDIT: make sure you did change the correct fuse. It should have been no bigger then a grain of rice and been very hard to see with out a magnifying glass.

 

[southbark33]

Well i could tell you a way that you could check to see if the fuse is any good,but now that you replaced the pioneer fuse with resistor it won't work. My guess is that the fuse is still good since you were getting signal to the amp. If that fuse was blown, you would get no sound. My only suggestion is to check all of your grounds and make sure that they are good.
EDIT: make sure you did change the correct fuse. It should have been no bigger then a grain of rice and been very hard to see with out a magnifying glass.

are you referring to the Pioneer HU's?

The Pioneer HU's have an external fuse, it's easily visible, birght red 10amp fuse that prevents too much power from passing thru the headunit, a safety feature. However, the fuse that I and most other people are talking about is the pico-fuse inside of the HU on the backside of the circuitboard. This fuse is what grounds the RCA preouts internally. If that internal pico fuse blows, you recieve overpowering engine whine, which is what I'm getting right now. I was searching through another forum with the same topic and they said that they fixed it removing the blown pico fuse and replacing it with a 1ohm 1/4 watt resistor, which is what most HU's have instead of a fuse.

I tried that method and it didn't work for me. I tested the connection between the pico fuse prior to taking it off and it wasn't giving me a reading.

Yes I def changed the correct one, I was referencing the schematics and the fuse was about the size of an eyelash with a little letter "p" on it, with the tag "FU-352" next to it.

 

[Cellmice]

Wow great sticky. After reading all the pages i fix my stupid wineing noise also. Been messing around with the system 3 days and after reading this and doing the ground the rca's it finally fix it.

Thank you very much everyone for the tips.

 

[WOT]

So how do you guys ground the rcas when the outputs arent right on the back of the headunit? :Like my RCA outputs off my pioneer have 8" cables so the connections isnt right on the back of the deck, how would you ground them still?

 

[95Prober 10+ year member]

so when i accelerate on the road, my engine whine increases, its especially bad while listening to the radio. for the most part, my music drowns out the whine when playing a cd

is this a typical alternator problem or Pioneer head unit, since thats what im running?

thx

 

[Blazin_Jason 10+ year member]

Just installed a p600ub yesterday and at low volumes it was making noise. I ran a ground directly from the battery to the head unit and it made no difference at all. Wrapped some 20g wire around the rear outputs and noise completely gone. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

 

[robinsonjerry 10+ year member]

this whine problem just happend to me. i have a clarion h/u grounding rcas only makes it louder my system has been the same for almost 2 years,it just started after i started my car one morning

 

[ultimate157 5,000+ posts]

Just installed a p600ub yesterday and at low volumes it was making noise. I ran a ground directly from the battery to the head unit and it made no difference at all. Wrapped some 20g wire around the rear outputs and noise completely gone. //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

Thats because the grounding issue is a loop contained within the head unit itself.

 

[MSUBlake827]

Anyone ever have a problem using two ground loop isolators on same vehicle? I installed one between my iPhone and my AUX in on the back of my headunit and then another one between my SUB OUT and my Input on my amp. When both are hooked up I get the same engine whine with really bad feedback through my subs that wasn't there before the isolators. But with just the one for my AUX in hooked up, there is no more engine whine. What is causing this?

 

[Blazin_Jason 10+ year member]

Thats because the grounding issue is a loop contained within the head unit itself.

Well my noise was gone for a while, but it has returned. I will have to see if the grounding I added came loose maybe. Might look into a 9886 instead.

 

[na_rsx 10+ year member]

okay, picked up a 780mp, i love the 880prs, but i love the look of the 880prs. well the 780mp had the horrible alt whine, so decided to do the rca ground trick.

had some remote wire, so i cut 6 pieces, put one in each rca, then tied all them together. then grabbed some kicker 16 gauge, found a screw on the headunit chassis. took of the screw, put the wire, tied everything together, wrapped it in electrical tape. and presto, **** is gone, its still there, but only 1%.

 

[big dawg 10+ year member]

I have an eclipse cd7000 and i have horrible engine noise. I put ground isolators on my preouts for my front and rear rca cables and they didnt help. I tried grounding them to my head unit and it didnt help. can anyone tell me where i can ground my headunit? In my 2001 bonneville, there is no metal behind the radio. Also, should i try to ground my rca cables at the amp as well? Could a bad amp ground cause this problem so badly?