On Tue, Oct 10, 2017 at 01:22:05AM +0000,
tonsil@... [korgpolyex] wrote:
> I don't think there's any problem with the patch memory. Once the EX-800 started producing sound (and I'm still not sure why it wasn't initially) I was able to go through all the presets successfully. I opened it up and checked the battery - it's in place on the main board. I didn't test it, but it looks like it's where it's supposed to be. I attached a photo of the insides.
>
There's not a lot to them. There are some extremely crappy circuit
diagrams out there (I've been telling myself I'll redraw them in Kicad
some wet weekend for about four years now) but essentially the signal
goes from the main board, to the chorus board, back to the panel board,
and then out.
From memory the audio in to the chorus board comes off the output of the
NJM2069 filter directly, and is one of the two screened leads going to
the chorus board (possibly pin 1 on the connector?).
There's a headphone output. Is the audio present at the headphone
output, or is that faulty too? That's driven by IIRC a couple of opamps
- the normal output is straight off the wiper of the volume control.
--
Gordonjcp MM0YEQ