Hacking a Roland CAMM3 PNC-3000

[mitarashidango]

I got a junk PNC-3000. While researching how to use it, I noticed something wrong with the z-axis DRO.

The value only increases when I raise or lower the z-axis.

I need a schematic for repair. And I want to know how to use it, so can you share the manual and other documents?

Best regards

[Doddy]

mitarashidango

I'll assume the DRO is a quadrature encoder - you'll get two outputs typically labelled "A" and "B". With quadrature encoding one of those signals is considered a "clock" (a pulse indicates travel), and the other indicates the direction of travel. It sounds like one of the outputs has failed (wire snapped, etc?), and it's just counting the clocks regardless of direction of travel. In theory you can test the quadrature outputs, assuming they're driven high/low with something as simple as a multimeter - each output will toggle high/low at the resolution of the DRO - you won't be able to (easier) test each discrete step, but you can check that some movement toggles the status easily enough. Be aware that you want the DRO in circuit to allow any decoder pull-ups to operate.