DrLomaX Posted November 22, 2005 Share Posted November 22, 2005 THhis thing http://www.radioshack.com/product/index.jsp?productId=2062214&cp=&kw=ground+loop&parentPage=search Link to comment Share on other sites More sharing options...
DrLomaX Posted November 29, 2005 Share Posted November 29, 2005 Good News!!! I have found the FM tuner trigger on the board. The pin goes 9V when you swtich to FM and 0.5V when you use CD and AM. A perfect place to use a pull up transistor to perform switching. I am now searching for the AM trigger. This is where I will use my AUX in. Also with the trigger you can automatically shut on/off yur aux devices when u switch modes. I will post pics once I am done. Had the wrong settings (AC instead of DC) on my oscilloscope and hence took a lot of time. Link to comment Share on other sites More sharing options...
DrLomaX Posted November 29, 2005 Share Posted November 29, 2005 I found the AM trigger also. It goes 4V when AM, and discharges to 0V when in CD or FM. Link to comment Share on other sites More sharing options...
foobark Posted November 29, 2005 Share Posted November 29, 2005 I'm missing what I think is a really cool bit of info here, can you school me a bit? There's a place on the board the has a signal charge during AM mode? Does that mean that you'd trigger your relay with that signal and replace AM? or would that mean every 'other' time you push the AM button you'd trigger your input? phew, okay enough with the questions Link to comment Share on other sites More sharing options...
DrLomaX Posted November 29, 2005 Share Posted November 29, 2005 The problem with our stereo is that the amplifiers do not channel the audio lines when you switch from one input to another, but they are switched off. So basically, if you run your CD player, your tuner box is shut off, if you run your tuner, your cd player is shut off. So there is no internal switching for the audio lines to the preamp. The author of this trhead mentioned this and I also tried it out. Now you can use the trigger(s) to switch on or off your audio signal to the circuit since your input is hardwired. Lucky for me, my PC has a remote out and I use that to control my audio input with the AM trigger using simple AND logic. You dont want to use a relay since they make a real big CLICK and throw a square wave on your speakers. I am going with a more sophisticated circuit to do the switching. I will post the schematic what I intend to do. Link to comment Share on other sites More sharing options...
DrLomaX Posted November 29, 2005 Share Posted November 29, 2005 FM trigger FM: 8.5V AM: 0V CD: 0V AM trigger FM: 0V AM: 4V CD: 0V You can use these voltages to drive a switch that goes NO or NC when you want your AUX in a particular mode. These pins are to the left of where this thread is focused on. Link to comment Share on other sites More sharing options...
OBieXT Posted December 1, 2005 Share Posted December 1, 2005 Dr. Lo, In one of the other threads on this topic, it was mentioned that the AM/FM/CD button could easily be modified for a 4th position in the downward direction by removing a plastic nub under the button. IIRC there's already a switch under the button in this position, but to use it required cutting traces on the circuit board which were quite small. Since you're thinking of using logic switching to control the audio function, perhaps you could tap into this button, without cutting the traces, and use the voltage transition to trigger the logic into AUX mode. You might then be able to use the AM or FM trigger voltages to switch the logic back to normal mode. That, or just turning the head unit off then back on would reset the logic into normal (non-AUX) mode. Link to comment Share on other sites More sharing options...
DrLomaX Posted December 1, 2005 Share Posted December 1, 2005 I am not aware of the four button being there. I will look more into that and get back to you. Thanks for the headsup tho. Link to comment Share on other sites More sharing options...
DrLomaX Posted December 1, 2005 Share Posted December 1, 2005 Dr. Lo, In one of the other threads on this topic, it was mentioned that the AM/FM/CD button could easily be modified for a 4th position in the downward direction by removing a plastic nub under the button. IIRC there's already a switch under the button in this position, but to use it required cutting traces on the circuit board which were quite small. Since you're thinking of using logic switching to control the audio function, perhaps you could tap into this button, without cutting the traces, and use the voltage transition to trigger the logic into AUX mode. You might then be able to use the AM or FM trigger voltages to switch the logic back to normal mode. That, or just turning the head unit off then back on would reset the logic into normal (non-AUX) mode. Do you know what traces need to be cut? I cut the nub and now the switch is free. Link to comment Share on other sites More sharing options...
DrLomaX Posted December 1, 2005 Share Posted December 1, 2005 Any decent design for handling a wide variety of inputs would need some active signal switching capability which isn't there. I have added some info about different trigger voltages at particular traces. you could use this as active signaling. I am trying to work the fourth button right now. Anyone know which traces need to be modified to get it to worK? Link to comment Share on other sites More sharing options...
OBieXT Posted December 6, 2005 Share Posted December 6, 2005 I'm not sure which traces to cut but here is a thread that talks about the subject in a few places. Looks like mvigneau is working on a similar solution. http://www.legacygt.com/forums/showthread.php?t=18870&highlight=traces Link to comment Share on other sites More sharing options...
DrLomaX Posted December 6, 2005 Share Posted December 6, 2005 Yeh I saw that thread. Its gonna cost me some money to get that info. I'm just gonna go with my way. I dont use AM anyway. Link to comment Share on other sites More sharing options...
mvigneau Posted December 6, 2005 Share Posted December 6, 2005 I can send you more detailed instructions on which lines to cut if you want...or you can use an Ohmeter (as I did) to figure it out? Or if you want, you can send me your board and I can do it for you?? It takes some fine soldering with 30 guage (AWG) wire. No Silent CD Aux-In Solution Link to comment Share on other sites More sharing options...
agctr Posted December 7, 2005 Share Posted December 7, 2005 I know what the answer will be but has anyone found a walk around for the McIntosh System as of yet. TIA. Ada///M. Link to comment Share on other sites More sharing options...
DrLomaX Posted December 7, 2005 Share Posted December 7, 2005 I can send you more detailed instructions on which lines to cut if you want...or you can use an Ohmeter (as I did) to figure it out? Or if you want, you can send me your board and I can do it for you?? It takes some fine soldering with 30 guage (AWG) wire. Prolly gonna stick with my method. Will let you know otherwise. Thanks for the offer though. I appreciate it. Link to comment Share on other sites More sharing options...
justinbeck Posted December 10, 2005 Share Posted December 10, 2005 In my case, I'm using a Belkin iPod adapter, one that plugs into the iPod's dock connector. The adapter powers and recharges the iPod, and has its own audio output with its own volume control, independent from the iPod's own volume setting. Nice... Which Belkin adaptor did you use and how did you wire it up? Do you know if the same adapter will work with a Nano? Also, where did you get power to run to the switch/relay? I realize that you are using the leftover from your FM transmitter setup, but where did you connect it to get power? Thanks for a great post, BTW, I'm doing my research and gathering what I need to get this done. I'll be pumped when I finally get around to it. When I do mine I'll be taking lots of pictures so I'll be sure to post them. Thanks again! Link to comment Share on other sites More sharing options...
ipoduser Posted December 10, 2005 Author Share Posted December 10, 2005 Nice... Which Belkin adaptor did you use and how did you wire it up? Do you know if the same adapter will work with a Nano? I used this Belkin adapter (which I found at Best Buy): Auto Kit for iPod w/ Dock Connector F8V7058-APL The Nano's dock connector is the same as a full-sized iPod's dock connector, so there's no reason that you shouldn't be able to use the same adapter. Also, where did you get power to run to the switch/relay? For the switch, I used the 12V line available on the inside of the head unit, right off the back of the audio system connector (as per the diagram at the start of the thread). For powering the Belkin iPod adapter, I tapped into the back of the cigarette lighter, using one of these car accessory power adapters from Radio Shack: Car Power Adapter with Battery Clips I cut off the power adapter's bulky clamps and soldered the remaining leads to the power connections on the back of the cigarette lighter. The end of the adapter opposite the cut-off clamps is an in-line lighter-style 12V power socket, into which I inserted the Belkin adapter so it can receive power with all of the wiring remaining inside the dashboard. Link to comment Share on other sites More sharing options...
DAP Posted December 12, 2005 Share Posted December 12, 2005 Dr. Lo, In one of the other threads on this topic, it was mentioned that the AM/FM/CD button could easily be modified for a 4th position in the downward direction by removing a plastic nub under the button. IIRC there's already a switch under the button in this position, but to use it required cutting traces on the circuit board which were quite small. Since you're thinking of using logic switching to control the audio function, perhaps you could tap into this button, without cutting the traces, and use the voltage transition to trigger the logic into AUX mode. You might then be able to use the AM or FM trigger voltages to switch the logic back to normal mode. That, or just turning the head unit off then back on would reset the logic into normal (non-AUX) mode. If you remove the "plastic nub", what does the system do when you press the button? Link to comment Share on other sites More sharing options...
DrLomaX Posted December 12, 2005 Share Posted December 12, 2005 I tried it, it does not do anything directly, although I did expect the satelitte radio LED to glow since you can see it in the led array. But I think mvigneau has made something that works around those line. I am fabricating my own little PCB that will switch ON/OFF when in AM along with AUX device. Link to comment Share on other sites More sharing options...
DrLomaX Posted January 16, 2006 Share Posted January 16, 2006 Has anyone opened the MP3 headunit from VDC. Are the traces in the interested area similar to what we are looking at? Link to comment Share on other sites More sharing options...
Spawn11587 Posted February 19, 2006 Share Posted February 19, 2006 bump Link to comment Share on other sites More sharing options...
fiid Posted February 20, 2006 Share Posted February 20, 2006 I just did this modification - I basically just added a DPDT switch (I just went ahead and drilled the front plate of the stereo - it's such a small switch that it's not very invasive). I ran the cable under the center console to the storage bin where there is a belkin charger unit with the dock connector on the end of that. The whole thing works like a charm. There is a clunk noise when the switch is toggled, and it will mix the CD with the iPod, but this is a case of "is it possible to use the iPod" not a case of "what would be the ultimate iPod setup". Just want to thank you guys for finding the right PCB traces. I'm SO happy to be able to listen to the iPod in the car. :) Link to comment Share on other sites More sharing options...
wiz561 Posted March 10, 2006 Share Posted March 10, 2006 Hi! I'm probably going to be looking at doing this-this weekend. Just wondering if there has been any updates, or if I should follow the original post about using the switch and the pinouts. I got a little confused in the thread where people started talking about thumping and how to avoid it. Thanks in advance for any tips! Link to comment Share on other sites More sharing options...
mvigneau Posted March 11, 2006 Share Posted March 11, 2006 I would do the switch as I am having a problem with my board not switching yet...but I am working on it...unfortunately, I may have missed the boat on this. No Silent CD Aux-In Solution Link to comment Share on other sites More sharing options...
fzanetti Posted March 11, 2006 Share Posted March 11, 2006 Great set up man!! Congratulations.... Flavio ZanettiBoston, MA Link to comment Share on other sites More sharing options...
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