Hi there,
I have a Sony HCD-EP303 Stereo that has radio, CD and cassete players, but no Auxiliary input. So I'm adding one.
I have opened it to check what it looked like, then I got the service manual. I'm not sure if it's legal to post it here, but some of you may "have it" laying around...
Anyway, I found that the IC that receives the outputs from the 3 sources and sends them to the amp has two unused input pins (L+R) that, according to the IC schematic in the manual, are connected internally.
See here, pins 12 (L1) and 19 (R1) are not connected:
And the IC schematic:
So... This sounds like the perfect place to wire the new input, if the PCB isn't shorting them with L2 and R2 (I don't have the stereo with me right now). However, I have no idea if I can just connect the output of an MP3 player (or something else) to it. Are the voltages compatible? Do I need some kind of decoupling capacitor or something? The CD, cassette and tuner inputs have 0.1uF capacitors in series as you can see.
Also, would it be better to just intercept the signal from, say, the CD player and have my signal use the same circuit? It could be done with those 3.5mm stereo ports that close one circuit when no jack is present and connect the jack to the circuit when inserted, disconnecting the original circuit.
Thanks!
F S
I have a Sony HCD-EP303 Stereo that has radio, CD and cassete players, but no Auxiliary input. So I'm adding one.
I have opened it to check what it looked like, then I got the service manual. I'm not sure if it's legal to post it here, but some of you may "have it" laying around...
Anyway, I found that the IC that receives the outputs from the 3 sources and sends them to the amp has two unused input pins (L+R) that, according to the IC schematic in the manual, are connected internally.
See here, pins 12 (L1) and 19 (R1) are not connected:
And the IC schematic:
So... This sounds like the perfect place to wire the new input, if the PCB isn't shorting them with L2 and R2 (I don't have the stereo with me right now). However, I have no idea if I can just connect the output of an MP3 player (or something else) to it. Are the voltages compatible? Do I need some kind of decoupling capacitor or something? The CD, cassette and tuner inputs have 0.1uF capacitors in series as you can see.
Also, would it be better to just intercept the signal from, say, the CD player and have my signal use the same circuit? It could be done with those 3.5mm stereo ports that close one circuit when no jack is present and connect the jack to the circuit when inserted, disconnecting the original circuit.
Thanks!
F S