Editing Atari 1025 Troubleshooting (section)

== Carriage, print head and line feed ==

{| class="wikitable styled-table" style="width:100%;"
|+'''Sams service checks (CP21)'''
! Symptom !! Checks, in order
|-
| Carriage does not move || With the printer off, move the carriage to the right and switch on: it should return home. Check for 26 V at pins 5 and 6 of CN4; check 7.37 MHz at pins 18 and 19 of Q8 and substitute the crystal OSC1 if wrong; measure the carriage motor windings; substitute Q8, then the board.
|-
| Print head does not print || Check connector CN3; check 26 V at D26; measure the print head resistances; substitute Q8, then the board.
|-
| Missing dots || Clean the print head face; check CN3; check the flat cable for a broken or pinched lead; measure the head resistances; substitute the head, then the board.
|-
| No line feed || Check CN5; measure the line feed motor; check 26 V at pins 5 and 6 of CN5; substitute the board. If the line feed is erratic or stops, look for broken gears on the left-hand side.
|-
| Will not print from the computer || Check CN6 or CN7, the cable from the computer, and the board.
|}

Atari's line feed flowchart checks whether any pins of CN5 are shorted together, which means a new line feed motor, then runs the self test and looks for a 5 V peak-to-peak signal at least every 15 seconds on pins 33-36 of Q5. If it is missing, replace Q5, Q8, Q7 and Q6 in turn; if it is present, the fault is Q3, TRA2 or an open line from those pins.<ref name="fsm" />