IBM 5150 Hardware Maintenance Manual page 157

Error
Description
Diagnostic Action
Forms Do
8. Position Printer Power switch to OFF.
Not Advance
Advance forms by turning forms advance
knob. Check intermediate gear for worn or
Overprin ting
broken teeth. Replace gears if damaged.
Check left and right tractors for broken
Forms
feedpins. Replace if broken. (See Section 3,
Jamming or
"Removal/Replacement.")
Tearing
9.
Check for 45 ohms resistance on forms feed
motor coils between pin CN6-14 and pins
CN6-25, 26, 27, and 28 on Driver Circuit
card (see Section 5, "Locations").
Resistance
=
45 ohms?
YES: Check for +24 Vdc at CN3-18. (See
Section 5, "Locations.")
+24 Vdc?
YES:
Replace both Control cards
(see Section 3, "Removal/
Replacement").
NO: See page 1400-6, "Power
Supply Check."
NO:
Replace Print Mechanism assembly
(see Section 3, "Removal/
Replacement").
1400-16