I need your help people... lots of you are into audio stuff so I am hoping one of you will know the answer.
I have just been given a car stereo for repair. First circle of friend and he is not a time waster and first time he ever asks me to fix anything... so I agreed to " have a look " at his piece of junk. It a double DIN / height modern thing that does everything and anything, with a big LCD screen, can display video from front or rear camera on the vehicle, TV, wireless or wired, USB, all sorts of I/O. It's less than a year old, still under warranty but the seller apparently is so great that he won't take responsibility for it. Only matched by the quality of the unit itself : 100% chinesium, the worse kind : there isn't even a BRAND name or model written on it, nada ! You just don't know what it is, nor who made it. Only thing you have is a sticker with a wiring diagram/ pinout for the very many connectors this thing carries at the back !!!!
Owner said the problem is taht the screen is dead, black, no picture no matter what.. BUT that the unit still powers up and that if he blindly plays with the knobs, unit seem to operate normally and he can listen to radio and what not. So I thought OK looks like it's just a dead display, might be worth having a look at it, especially since unit is so new and cost so much money, 300 Euros... a fortune for chinese crap that's not even branded/identified !
So I have this thing on the bench, actually very service friendly can't complain. Easy to split and the mother board is perfectly accessible with all the components on the top side, great. Front panel assembly show you the component side of the LCD board, where I can see the connector tghat goes to the backlight, and the board carries a couple SMPS. So I can easily test the backlight and make sure the SMSP work as well.
So I give the unit power and ground... press the pwoer button but... it does not wake up ! And the ammeter shows that the unit draws 0.000mA, not a mA ! Weird....
So I am here to ask those in the know here, who are used to wiring modern car stereo... is there some other input I need to wire up other than ground and battery / +12V, the twxo beefy wires, to get the thing to power up ?? I see the unit is connected to the freaking CAN Bus of the car !
There is an external little box supplied with the stereo, that reads " CAN Bus decoder ". Whatever that does. I plugged it in, but no joy either.
Could a problem with the can bus, or lack there of, prevent the unit from powering up ? Do I really need to have CAN working to xwake up the stereo ? That means I can't debug the unit on my work bench then ?!
Also there are other inputs whose name sounds mysterious, maybe they need to be wired as well, I don't know. See close up picture of the pinout diagtram below :
(1) Steering Wheel KEY 1
(2) Steering Wheel KEY 2
(11) CAN BUS TXD
(12) CAN BUS RXD
(14) BRAKE. I guess it means brake pedal...
(17) ILL ...like in "Illumination" / backlight ? I see that this wire goes straight to the external can bus decoder box...
(18) ACC ... accelerator ? They monitor the brake pedal so why not the Accelerator pedal
(19) ANT .... "Antenna" I guess ? Power feed to extend a telescopic antenna ? Or power a roof mounted amplified antenna ?
(20) REVERSE : I guess it means reverse GEAR, probably used to automatically switch to the rear view camera video feed...
Pedals, antenna, reverse gear, I guess I can safely ignore.
However ACC not sure, ILL not sure either, CAN bus I am scared, and steering wheel KEY 1 and 2 scared too...
Please help poor Vince, how the fuck can I wire this thing on my bench to get it to power up and draw some current ! If AT ALL possible ?!