Radio/CD suddenly dead

[CTScott]

Originally Posted by bobolinko

Hi CT,
I have a question to that end...
My Scion XD stereo looses all the presets when the battery is removed, but remembers EVERYTHING when I disconnect the power cable (battery power still live) from the unit and remove the head unit and store it, even for a year or more... What's the goings on here?

I cannot understand why this happens, but it does. Did it more than once, and on more than one car.

Thanks!

At first I was thinking you are nuts, but then I realized that the radio probably has a super cap for memory backup. When you remove the radio it keeps the CMOS alive for a long time, but when you leave it in circuit, it tries to power the rest of the car when you pull the battery cable. Put a general purpose diode (1N4001, etc) in line with the constant battery power wire, with the white line facing towards the radio. That will prevent it from back feeding the rest of the car.