I realize this is an old thread but am posting this as a cheap and easy fix for future readers of this thread having the same issue. There are only 2 parts needed to resolve this issue: 2200uF capacitor @ 16vdc (or higher - I used 35v) and a rectifier diode (stripped end toward capacitor). Here is the part numbers if the parts I used on my Pioneer AVH-4100NEX:
IN4004 Rectifier Diode #276-1103 by RadioShack
2200uF Electrolytic Capacitor #272-1020 By RadioShack
You will need to cut the radio's ACC wire (usually red) and solder both the striped end of the diode and the positive end (black, in
