Service manual

7: Troubleshooting Guide
CHRISTIE INC. CHRISTIE INC. - - 35/70 Service/PM Manual
July, 1997
READY DIAGNOSTIC TABLE
4-2
Loop set does not function, Pulldown System –
CONDITION 2: Film is moved from the upper loop to the lower loop and then
back to the upper loop but does not stop.
Step Diagnostic Result
Verify that the index and the 90-degree signal from the Pulldown
Sensor do pass though the 2276 card and reach U10 pin 11 and U19 pin
3 on the 2293 card. Isolate problem to the sensor, the 2276 card, or the
wiring. If not any of these, replace the 2293 card.
4-3
Loop set does not function, Pulldown System –
CONDITION 3: Film does not move until after 2 seconds and then only moves
from the lower loop to the upper loop.
Step Diagnostic Result
1 Check the 8-amp fuse (fuse 1) associated with the -34 volt supply of the
Pulldown system. Verify that the -34 volt supply does reach the 2275
card.
2 Verify that the input to the 2275 card, at R102, or at TP12 on the 2293,
goes positive for the first 2 seconds and then goes negative as film
moves up. If the voltage is not correct replace the 2293 card. If the
voltage is correct, replace the 2275 card.
4-4
Loop set does not function, Pulldown System –
CONDITION 4: The Pulldown sprocket turns with enough force or speed to trip
the buckle switch or damage film.
Step Diagnostic Result
Replace the 2275 card.
4-5
Loop set does not function, Pulldown System –
CONDITION 5: The Pulldown sprocket starts a Loop Set operation, but stops
part way. Loop Set will continue or complete if film loop is restarted with assist
by hand.
Step Diagnostic Result
This indicates worn brushes in the Pulldown motor. Replace brushes
or motor.
Table 7.8: READY Diagnostic Table (Continued)