Sony DPP-EX7 Service Manual page 32

2. Ribbon trouble
Trouble: The ribbon is wound round the capstan roller and cannot be taken out. (Ribbon jamming)
Cause: . Abnormal ribbon cassette
. Abnormal installation position of ribbon guide
. Abnormal chassis assembly (Deterioration in take-up reel clutch torque or ribbon path
abnormality due to chassis deformation)
. Remove the mechanical deck block from the lower cabinet, turn the gear engaged with the
Remedy:
stepping motor gear, and eliminate the ribbon.
. Confirm that the ribbon guide is fixed in parallel with the heat sink and in the non-floating
state.
(If the ribbon guide is not fixed in the conditions above)
Loosen the fixing screw and fix the ribbon guide again.
. Replace the chassis assembly if it is abnormal.
3. Print trouble
. Paper is not fed from the paper feed tray.
Trouble:
. Abnormality is detected at equal pitch intervals in the paper feed direction of the printed
side.
n
An abnormal point can be confirmed according to the interval of a pitch.
. Pitch interval of 18.8 mm: Pinch roller abnormality
. Pitch interval of 20.4 mm: Capstan roller abnormality
. Pitch interval of 37.7 mm: Platen roller abnormality
. Adhesion of dust or grease
Cause:
. Adhesion defect (in case of a pinch roller and platen roller)
. Welding defect (in case of a capstan roller)
. Remove the mechanical deck block from the lower cabinet and clean each roller. (For the
Remedy:
dust adhering to the capstan roller, eliminate it using a gum tape.)
Trouble: A stripe is detected in the paper feed direction of the printed side.
. Adhension of foreign objects to the thermal head surface
Cause:
. Broken thermal head
. Flaw and scar on ribbon guide
. Flaw and burr on the printed side of paper path of K (paper feed) frame assembly
Remedy: As for the streak caused by the adhesion of foreign objects to the thermal head surface can be
improved by cleaning the surface. Clean the surface using a cloth dampened with ethyl
alcohol back and forth several times. When the trouble persists even after cleaning, replace
other faulty parts that may cause the trouble.
4-6
DPP-EX7 V1