Commodore 1515 Technical Manual page 43

8. The upper and lower dots of printed characters are too light.
START
Proper position
NO
of print head unit?
NO
YES
Replace it.
9. Printings are too light.
Refer to "6. No printing or poor print quality."
10. Smudging by ribbon.
START
Proper position
of print head unit?
YES
Any foreign object
on platen or print
head unit?
YES
Remove it and clean.
NO
NO
NO
41
Adjust it.
Reset it.
Replace print
head unit.
Reset it. If ribbon is twisted,
correct it.
Adjust it.
Repiace print head unit.