Casio WK-3200 line in mod?

[behealed]

Hey I have a Casio WK-3200 and the one feature which I so badly wish it had was a line-in jack. I was wondering if anyone has any knowledge on how to custom add one. I did open up my casio and take a look inside, and as far as I can tell it has 4 different sound lines, one for each speaker (it has two woofers and two tweeters). The 4 sound lines all go through the volume control knob, aparently at full speaker volume. All the volume control knob appears to do is diminish the already-amplified sound. It appears that the 4 sound lines never actually mix anywhere, except maybe to go out the headphones jack. But that does me no good for finding a spot to add some line-in wires. Anyone with ideas?

[the_zombiest]

To my knowledge, which is limited by the way, you can only install a line-in on keyboards/toys that have an in-built microphone. 

[Circuitbenders]

i suspect that the only way you are going to manage this is to trace back the circuit until you find the input to the amp section and build a small passive mixer circuit to feed in your external signal at that point. I'd be willing to bet that theres only one amp circuit for stereo left & right and the signal then goes through a speaker crossover to feed the different speakers.

On the other hand, it might not even have a crossover and might just feed the full signal to each speaker and let the speaker reproduce what it can manage. It'd be a very inefficient way of doing things but i wouldn't be surprised

[casiologie]

Basically I have answered "behealed" already in this thread:

http://www.jz-server.de/forum2/e107_plugins/forum/forum_viewtopic.php?334