sparkyg60 0 Posted April 11, 2004 Hi All, Hopefully someone will be able to help me on this. Re-installed my amp and now it does not switch on ! I've narrowed it down to the remote amp switch on cable. If I bridge the main power to remote switch on on the amp it fires up. :? I have tested the remote amp lead at the headunit, as there is voltage. I have also tested the cable at the amp end, and there is voltage, but only about 0.1 or 2 at both points - is this too low to turn the amp on ? Any help appreciated. Thnx Mark Quote Share this post Link to post Share on other sites
andycowuk 0 Posted April 11, 2004 disconnect the wire at both ends......find a good earth on the bidy somewhere, and check for continuity between the remote cable any the body.....obviously there should be none...but if there is, u know the wires shagged. get back to us once u done that..... Quote Share this post Link to post Share on other sites
stevemac 0 Posted April 11, 2004 If the voltage output is the same at the amp end & also at the head unit - I doubt your cable is the problem. If you're not loosing any power in the cable itself then it's okay. I always take the switchable amp feed from the electric aerial output of the head unit - often a thin black wire. This wire carries a very short pulse of power when the r/c unit is switched on & another short pulse of power when the r/c is switched off. Quote Share this post Link to post Share on other sites
andycowuk 0 Posted April 11, 2004 sinse it is one continuos lenght of wire, all parts of it are at the same potential. If the sleeve is damaged, then there may be a short to earth at the damaged section. If there is a short then theoretically the wire should be at the same potential as the body, ie potential difference of 0v However, in paractice there is a resistance in the wire and also in the short (the electrical connection between the wire and the body, due to oxide layers, physical connection area, capacitiance of two metal areas). Therefore there will be a small voltage drop across the wire...perhaps around 100 to 200mV. Quote Share this post Link to post Share on other sites
sparkyg60 0 Posted April 13, 2004 disconnect the wire at both ends......find a good earth on the bidy somewhere, and check for continuity between the remote cable any the body.....obviously there should be none...but if there is, u know the wires shagged. Ok, done some testing, when I turn on the h/u there is around 0.1 - 0.3 volts with the wire grounded to the body. So that means it's shagged ? - really odd, coz it used to work. The amp was taken out last year to move the phono cables to the other side of the car, all live wires were taped up. The only thing different is the amplified aerial is now working (didn't use to !). Thanks. Mark Quote Share this post Link to post Share on other sites
andycowuk 0 Posted April 13, 2004 I am not sure u have done the right thing....your unit of measurement is wrong! you should be testing for resistance between the body and the wire, not voltage.....is that what you did? with the wire diesconected at both ends, there should be no voltage difference, because there is no source. Quote Share this post Link to post Share on other sites
sparkyg60 0 Posted April 13, 2004 :oops: sorry misread your earlier post, I was trying to avoid removing the headunit, but I'll give it a go to test the wire ! :oops: Quote Share this post Link to post Share on other sites
