First scanner advice needed, right step into scanners?

Just glancing through it looks like you might be shorting out half your signal to ground due to your connections. Just a guess.

SOLVED!! F***ING Windows. Some directshow audio codec was downmixing audio channels and some of the XY galvo signals from the first two channels were going to TTL signal, and thus interfering with the +5V of the TTL signal. Thus when the galvo X signal goes above 0V, TTL signal blanks seing the half vertical ILDA test image I was seing. How I noticed that? Easy. First double checked hardware, all ok. double checked galvos, all ok. So I plug earphones to output signals on the Audio board. When plugged in XY channel I heard a blasting sound, seems ok (I thougt). But when I plug them in the corresponding TTL channel I heard again that blasting sound!!. This time I symply double-checked software. Made my own Wave player through the Windows API waveout function (I am a C++ programmer) to play laserboy waves and voila! problem solved.

Now the next thing to do is a housing, I hope that housing it will be easier than build it, we'll see.

Thanks again for your time.