Hi all,
Is it true that there is a fuse somewhere inside the HU (0.5A or so) which is for the RCA tracks or something?

I was speaking to a guy the other day, and he said that some of the 'engine whine' noise (it's definately not this though) could be due to a blown fuse inside the HU itself.

I am 100% sure that it's not engine whine as if I connect hi-low level convertors in the speaker lines, and RCA's to that, there is no noise at all, which indicates it's in the RCA tracks somewhere.

My question: The HU is not under warranty, so if this is the case how hard is it to pull the HU apart and replace this fuse myself?

Cheers! :)

might be a good idea to let the pro's to start opening up your headunit and replacing the parts inside, its not something you want to do yourself unless you know what you are doing

and the engine whine noise you can normally get rid of it by adding another ground from the battery to the chassy, 4ga minimum

Quite often it looks like a resistor, but smaller (and usually white/blue, the screen printing will usually show a fuse logo or the component will be called f1 or f2 or fwhatever).

Also, often it is just a thinner section of PCB track that is designed as a fuse :doubt:

Cheers
Heath Young

Quite often it looks like a resistor, but smaller (and usually white/blue, the screen printing will usually show a fuse logo or the component will be called f1 or f2 or fwhatever).

Also, often it is just a thinner section of PCB track that is designed as a fuse :doubt:

Cheers
Heath Young

Ahh... ok... Well that just sucks! lol

If it's designed to be a part of the PCB track though, wouldn't blowing that 'fuse' cause an open circuit, and thus no noise out of the RCA's?

Are those fuses able to be bought easily?

No. The RCA ground is internally connected to a chassis ground.

If you were to pass it through an isolation transformer, you will get no output (as there is no earth return to the input windings).

Because your amplifier has a connection to ground (either via the chassis or by your RCA's (which is what killed them in the first place)) it will still work. But you have different ground potentials front and rear, so any voltages will be imposed across the inputs, hence the noise.

This is why unbalanced audio is a bad idea... But there are (AFAIK) no balanced headunits/amplifiers for automotive use.

BTW - those little fuses are a bastard to track down, better off getting them through farnell etc. or just bridging them with wire (what a LOT of service techs would do anyway)

Cheers
Heath Young

Legend! Cheers!
I'll look into it after exams :D

Pioneer deck?

Pioneer deck?

Yeah.... How'd you guess? lol

DEH-P1Y

:bowrofl: Im going through the same shyt. Its good that it protects the output stage but yeah no idea whats going to happen with it.

Ill let you know what they say about mine if I hear anything soon ( put it in on tuesday ).

And as for doing it yourself, apparently it is case of taking the covers off and removing the cd player unit and it is under that somewhere.

Ok cheers!
Can you pm me the price too once you've found out please :)

Under the CD unit..... :think: ... I wonder how hard that's gonna be to get to....

Mine should be done under warranty. Bought a 8650mp off a JB demo board with 5yr warranty. Only just hooked up an amp for the front stage some 6months after I got it and yeah, noise everywhere. Was like that when I bought it though cause when I sold the Magna I hooked it up to have a play while I was taking my old deck out and noticed the noise then....

If they charge me ill blow up so hard. But at least if they quote ill let you know how much :bowrofl:

I had the tracks fixed on my DEH-6850MP a few weeks ago. Didn't cost me a cent - the guy from Autobarn said that Pioneer do it for free the first time, then charge if it happens again.

I had the tracks fixed on my DEH-6850MP a few weeks ago. Didn't cost me a cent - the guy from Autobarn said that Pioneer do it for free the first time, then charge if it happens again.

Really!? :shock: Very interesting....

Is there any way to determine whether it's the tracks for sure then?

Yeah - plug an isolating transformer in and see if you get anything out the other side.

Or, plug the RCA leads into an external (mains) amplifier - since it doesn't share a ground with your car, it wont work.

Cheers
Heath Young

I had the tracks fixed on my DEH-6850MP a few weeks ago. Didn't cost me a cent - the guy from Autobarn said that Pioneer do it for free the first time, then charge if it happens again.

How long did yours take to get done?

Yeah - plug an isolating transformer in and see if you get anything out the other side.

Or, plug the RCA leads into an external (mains) amplifier - since it doesn't share a ground with your car, it wont work.

Cheers
Heath Young

This one would be easier for me... Why won't it work if there's no common ground?
I woulda thought it'd still work as it's just sending an AC signal down the RCA's... This signal would then go through the external amp, and make noise at the other end... :confused:

How long did yours take to get done?

Dropped it in at Autobarn one day, and they received it back 3 weeks and a day later.


Is there any way to determine whether it's the tracks for sure then?

Apparently it's a common fault with Pioneer headunits... my amplifier has been un-grounded on three occasions, and I had noise through my speakers, so I just figured that it was the tracks :D Turns out I was right, according to the guys at Pioneer, they were oh-so-close to being completely stuffed.

This one would be easier for me... Why won't it work if there's no common ground?
I woulda thought it'd still work as it's just sending an AC signal down the RCA's... This signal would then go through the external amp, and make noise at the other end... :confused:

Cause it needs a return path to complete the circuit. No complete circuit, no current will flow and nothing will happen.

Cheers
Heath Young

Woot mine is back!! Took 9 days. Now I have music again!! :D