Ian, a while back you posted some pics of early radios:
http://www.sunbeamalpine.org/plugins/p2_news/printarticle.php?p2_articleid=13
The Radiomobile 500T shown is the same as my friend Brent Kasl in Nebraska is trying to re-install in his now-converted-to-Neg-earth car. I think the best solution for him - and many others with similar issues- is to use a converter / adapter designed for powering a notebook PC in a car. These are readily available for $25 or so, with a 12-13.7V input and available in a wide range of output voltages and power capacity. I am 95% sure that most of these are isolated between In to Out (i.e. no common ground) and could therefore be used to easily solve the Pos Gnd/ Neg Gnd problems by simply reversing the output wires of the adapter.
Before we buy one of these it would help to understand what the 500T requires. Do you have any idea of its power requirements? At least maybe what amp fuse it calls for ? And can you explain to me if the 500T has a separate power supply or some other added box. From photo #2, there seems to be a separate chassis located behind the speaker box. Brent tells me that his 500T has some separate box with heat sink type fins on it, but neither he nor I know if that is part of the actual 500T or if it's some aftermarket amplifer. And he's too far away for me to look at it.
Thanks,
Tom
http://www.sunbeamalpine.org/plugins/p2_news/printarticle.php?p2_articleid=13
The Radiomobile 500T shown is the same as my friend Brent Kasl in Nebraska is trying to re-install in his now-converted-to-Neg-earth car. I think the best solution for him - and many others with similar issues- is to use a converter / adapter designed for powering a notebook PC in a car. These are readily available for $25 or so, with a 12-13.7V input and available in a wide range of output voltages and power capacity. I am 95% sure that most of these are isolated between In to Out (i.e. no common ground) and could therefore be used to easily solve the Pos Gnd/ Neg Gnd problems by simply reversing the output wires of the adapter.
Before we buy one of these it would help to understand what the 500T requires. Do you have any idea of its power requirements? At least maybe what amp fuse it calls for ? And can you explain to me if the 500T has a separate power supply or some other added box. From photo #2, there seems to be a separate chassis located behind the speaker box. Brent tells me that his 500T has some separate box with heat sink type fins on it, but neither he nor I know if that is part of the actual 500T or if it's some aftermarket amplifer. And he's too far away for me to look at it.
Thanks,
Tom