Laserjet 3015 scanner failure

[fredwood]

I've got an older 3015 AIO that just started giving me a scanner problem.  Half of a scanned page scans vertically black.  Unit prints fine.   I found a diagnostic "calibration graph" and tried the red channel, I get a nice curve which then either drops to nothing or infinity, can't tell which. 

Is this a symptom of a scanner unit failure?  Or should I look at connections, motor, or memory?  I want to have the right part on hand if possible when I take the thing apart, because it looks like it's not easy from the service manual.

Any other diagnostics that might help pin things down? 

thank you!

[fredwood]

Attached is what a scan looks like.  Wished I'd saved the other orientation, but imagine a robust graph in the upper right corner, which then falls directly into the line you see in the middle left margin, if you can.

[fredwood · Accepted solution]

So, just to close out this topic, it did turn out to be a scanner failure.  My theory is that the scanner is lit by LEDs from both sides of the page, and one bank failed.  The part number for this printer was RM1-0927, which I got by taking it apart.

Half hour or so and a donor parts printer that coughed up its own working version, and I'm back in business.