what i'm trying to do is just get it to turn on as if I had turned the ignition on. Any ideas on how I could get it to do this. Or any ideas where I could get a wiring diagram from? Pics below
I'm not sure, but I would guess that as long as it's powered to the right level, it's on. Have you tried that?
i've thought about doing that, the thing is i don't know what to apply to what pin, positive or negative and what voltage as I don't wana short it all out or fry it
Well, to be honest with you, I would probably run some temp wires from the header of the base unit and plug in the headunit and turn it on and use a DMM to figure out which one was power and ground. Then just use that info. You'd have to use extremely small wires, but you can get shielded freakin' small wires (that's the official name ) from an electronics store (the really thin shielded red wire is what I prefer ). Regards
i have tryed doin that, but the reason i have pulled apart a 200 quid head unit coz ithe main section went bang in my car with lots of smoke. i know the front still works as it works on my mates cd player, but i don't think he'd take it too nicely if i asked to pull it apart and attach wires to it!
Do you have access to the busted base unit? Perhaps the internal PCBs give some hint as to the header's pinouts. Or, you could just run a continuity tester to the header and test points on the PCBs (if there are some). Looking at your pics, I THINK I see a 5V VDD test point on the back of that head unit. Run a continuity test across the pins of the header and that test point... that'll tell you if one has 5V going in. Do the same for a GND test point if you can find one. If you can't find one, see if you can look up some of the chips on the unit and see if you can find a pin that is supposed to be connected to GND. If you can find one power pin and one ground pin on the header, hook those up and see if you can turn it on. If not... well... more testing will be needed I think it'd be lots easier if you can pull apart the base unit and see exactly where those header pins go and come from.
ah cheers, what am i looking for with the test point, which area roughly. I've got a multimeter, is that what u mean to use to test it? I'll get some pics of the section it slots into tomorow
ah i see the area you mean, i'll try and get a better pic of it as i'm not sure of the exact area to test as there is a line with lots of points
Look at the writing on the PCB and sometimes it'll point to a via that is connected to a certain plane or line or something (it's how the companies really test their boards). I thought I saw one that said "VDD" but it's hard to see and blurry, so you'll get a better view from where you are (ie. real life ). Turn on your multimeter and see if there's a continuity option (usually this makes your MM beep if a 0 resistance is detected). You can do it with just the ohm meter option, but the beep makes it go faster (you can just run one end of your dmm along the header and wait til it beeps). On the picture, it's the back of the unit, bottom right corner.
finding ground on most pcbs is easy just do continuity test between one of the big areas of copper (scratch off the lamminate) and the pins to find your ground. +v i usually find by looking up the ics on the net and doing a continuity test from their +v pins to the headder pins of the object im pulling appart
big areas of copper? I guess you're talking about planes, but there are also voltage planes that is potentially a fatal mistake (for the device)
i usually check with the gnd on the chips too also check that the ICs dont need -ve voltages cos applying the + without the - will almost deff fry it
Just quickly looked through the pictures and there are some texts in the bottom left corner of the PCB. They seem to match the connector so maybe the pinout is printed there on the PCB ? Can you see the texts on the two big IC's ? The one on the right might be some memory. The other might be some microcontroller/ASIC with integrated display controller. I don't how the thing is designed but isn't it supposed to make it harder to steal those things and make it work afterwards ? So there could be some encrypted serial data lines in those connectors. Maybe it checks for some unique code that needs to be found in the other part before it starts working ? Sounds difficult... Also if the "brains" of the whole equipment are in the big chip then it has no interface for feeding anything the display rather the connector would be for the control unit to control the rest of the head unit. But this is all guessing as I don't know how that thing is done.
all the head unit would need is track information and commands to the base unit to make it... you know... do stuff. It is the brains simply because it drives the base unit, but the base unit still has all the guts. One is useless without the other, but it's not impossible to make the base unit work if you could figure out all the commands, then program a chip that would send those commands correctly to the base unit.... But surely someone that intelligent is intelligent enough not to steal
The face off works as a theft deterent by being bloody expensive to buy if you steal the main backing unit basically if theres no face plate some theiving scumbag has either a) got another face plate (but they cant tell what model the headunit is without the faceplate unless they've already nicked the main unit so pointless anyway) or b) just stolen an expesive doorstop, the face plate should work on an identical model so there shouldn't be any encrption involved. when i used to work in the trade we always had people asking for face plates and std practice is no reciept no face plate If you know anyone in the car stereo repair trade they should have a circuit diagram for the face plate, whether or not they'll let you have a copy is a different matter but its worth asking
