LXP-1 Problems

[abechap024]

So I have an LXP-1 on the desk...it powers up and works for about 3 seconds and then there is a "click/pop" and audio goes completely dead. Sometimes the midi light stays on, sometimes off, sometimes the LED over load light stays on also...very strange...

Also to complicate matters, or a ray of hope...I set the unit down (out of its case) so the bare PCB is resting on the footstool I had for testing and it runs fine....I lift it off the footstool and within seconds it "pops" and no sound. The footstool is fake leather so maybe its like a capacitance thing?

I've recapped the whole thing and replaced all opamps...

I've scoped the D/A and it seem when the "pop" happens, the digital info feeding the chip goes dead (along with the output) but I'm not 100% sure about this.

Any pointers would be great! Digital stuff still blows my mind....

 

[abechap024]

OK...well with a little bit of experimenting I was able to suss out the problem...
I think it is because the battery is really low, somehow some sort of capacitance or feedback within the circuit was building up and it was knocking out the clocking signal, I was able to shunt the crystal @ c21 (usually left unstuffed, at least with the verison 3) with a 15pf cap now its working great!