Print quality - squiggly lines ColorQube 8870

Hi.

I've been troubleshooting my ColorQube 8870.

All colours print these inconsistent squiggles. I've tried all the Troubleshooting items (Light Streaks, etc) and the Support items (like flushing ink).

I'm not particularly interested in a "take it to a service tech" answer, but any help diagnosing where the problem is would be helpful.

Thanks!