What are you tracing your lines with?
The HL-7 & 8 tracers require India Ink.
A Sharpie will not reflect enough light for the tracer to lock onto.
Did your system come with a manual?
Westinghouse had a very good service section and a test pattern printed on a page towards the rear of the manual.
Can you trace the test pattern?
If yes it is your ink and if not then try to adjust the Eye using 'Adjustments' section in the manual.
If you do not have a manual then contact Wescan Systems in Burlingtom Ontario.
They made the HL7 and still support it.
Robin is the service guy there.
Even though I am an old timer I never got into the tracing machines.
Mostly I took eyes off and replaced them with CNC's.
You can cut faster, and more efficiently with a CNC.