Cool as ICE

[chicaboo]

Hello hello,

The Fro master and I got our 6.5" LCD headunits on Friday. Now we are keen to see them running just for the sake of it before they are properly installed.
We tried running them off battery through spike protected leads with engine off and on, and they ackowledge the power with a beep, but won't switch on to full power to operate.
My theory is that they need the ACC(essory) wire to be connected to the ignition. Or the battery doesn't generate enough power to run them, and maybe they need to go through the alternator's power?
Since we don't have a wiring diagram off the Mazda loom, we don't know what is what without tracing all the wires back or guessing off the colours aswell... So we're thinking of getting a pro install with brackets made up for a snug fit too.
We'll also be prewiring leads for video in/out and the sub and MAYBE a possible centre front speaker? Will be running stocko speakers at first to guage the difference before choosing an amp or aftermarket speakers.
Hopefully when it's all done, it'll be a nice cheap setup that looks the goods. But in the meantime I'm just after some direction for the testing just to see it running before some tool has installed it and we can't access the rear panel without stuffing around.

Gav.

[goldsp]

ok the only wires concerning you should be : -illumination wire
-acc wire
-continuous power
-ground wire

illumination can be checked using multimeter and dimmer . readings should change as dimmer is played with.

acc wire using multimeter should show a reading of zero and when the ignition switch is turned to acc the multimeter reading should increase significantly.

continuous power is a quick way to blow a fuse and then you have to check all the fuses. this wire carry's power from the battery at 12v continuously and shows this on the multimeter when the car is turned off .

ground wire is usually a black wire (chunky black wire). in mazda its a chunky black wire if memory services correct.

these all connected should give you power and illumination gavstar


to connect speakers its a simple cass of a 9v battery and holding the striped wires across the terminals in their pairs. when you hear a buzz come from a speaker this is your e.g. front left or rear right.


i think i have just about covered it , if i have missed something someone just correct it or add it in.

when you have an amp there is an amp remote wirer which is usually blue or blue/white.

[Dogo]

If I heard a noise coming from a speaker that I'd connected to a 9v battery I'd be worried.

Being a DC power source, the cone should pop out or in and stay there. To make a buzz you'd need it to oscillate which would mean an AC source.

[twilightprotege]

the HU needs 2 sources of power. there is the continuous power from the battery (the beep you're getting), plus accessory power to tell the HU to turn on (although this is very very very small power - just enough to tell teh HU to switch on)

[chicaboo]

Thanks guys, that's a great help. Yeah when I got the beep I knew I had the power right, but I need to locate that "acc" wire to finish the job. I figured the acc lead didn't need much power and that's why I didn't play with it not fully understanding the consequences...
Any BJ owners got suggestions for places to prewire the sub to? I was thinking of taking the centre console out between the seats, and running the wires under the carpet to the passenger seat area for the future amp/sub, etc... There's a opening flap sort of thing in the carpet under the seat, do you guys reckon this is for wiring access? I don't know if it's worthwhile running signal leads to the other seat area or not for the future door speakers amp?

Gav.

[chicaboo]

Just a thought, could I put a + terminal from a grounded 9V battery to the acc wire just to fool the HU while I do some testing?

[Dogo]

possibly, but it depends on the HU.

some are picky about the strength of the signal from both power and accessories. This is usually to make sure they turn off if the battery goes low or if there's a short.

If the HU is not in the car yet and you have and old PC lying around you can turn the power supply into a 12v, 5v and 3v testing station.

[twilightprotege]

i';ve used that flap for wire access to my two amps.

just wait til you have the HU in the car. you dont wanna go blowing it up

[chicaboo]

I'm just anxious and want to get some things sorted out. I forgot that I also need to run my two video outs to under each seat too. And then I have another 2 video input that I need to have prewired for future use aswell...
In regard to using a PSU from a PC, does the PSU invert the power to DC to the 12V disk drive leads and 3.5/5V CPU leads? As much as I've had to do with PCs, I've never bothered learning the electrical science behind it, I've just built them...
Also, are there any tricks to convert the composite video out signal to S-Video or something similar to reduce chrominance and luminance crosshatching?

[twilightprotege]

good things come to those who wait

[goldsp]

9v battery is fine to test the location of your speakers DOGO. its a small ruffled noise for about 5 sec and i have done it many of times and have friends that do it and have car audio experience.

[Dogo]

thats cool i just dont get how a DC signal creates an oscillation to make noise.

it doesnt sound like something I'd be doing to my speakers.

connecting a battery to speakers is normally done to find out which terminal is negative and which is positive. If the cone pushes out, its positive, if it sucks in, its negative. But either way it should stay out or in and not move or make noise unless theres a bad connection somewhere.

it makes wiring easier and lets you ensure that all your speakers are in phase with each other - to avoid cancellation.

[mcwilly]

dont u just hook the accessories power up to the cigerette lighter, this way wen u put the car to accessories it turns on

[Dogo]

there should already be an accessories wire going to the old head unit harness.
No need to mess around with the lighter.

[goldsp]

yep no need to mess with lighter