Well this forum has been so useful, I figure it's time to give back! Recently I installed a Sony CDX-MP70 car stereo...and of course lost my dash controls. Searching online on other forums I came across the schematic for the Sony RM-X2S (RM-S4S). For those not familiar this is Sony's standard wired remote that controls the vast majority of Sony head units. So here are the details of how to get back your dash controls if you have a Sony head unit that is compatable with either the RM-X2S or RM-X4S. First off here's the schematic:


Note 2K2 implies 2.2 kohms of resistance, etc.

This is what my finished product looks like. The black rectangular looking thing is my resistor network insulated with shrink wrap.



Removing the covers we have:



Those white rectangulars are nothing more than switches...kinda like the one in the schematic above. The resistors are located on the right along with an ordinary 3.5mm female plug. Looking at the back of the pc board we have:




I would first deal with the trace cuts on the pc board. You can use an exacto know as I did, or a dremel tool. Whatever you do make sure that you have a good clean and wide cut. Otherwise the trace might short out later on, and you'll get some weird behavior (personal experience).

The switches have some pre-existing grounds. However, the mute button doesn't have one. Hence the additional black wire connection. Once completed button everything up and use a standard 3.5mm male-male cable and your set!

Enjoy!!!!

 

This is pretty cool! Good job!