1. Test overview.
This test is used to check that the belts of the APS film carrier is sufficiently tightened. This test is similar in its operation to that of MOTOR INTENSITY. This one having been made as a preliminary, the primary tension belt is consequently correct. If the test APS motor intensity fails, this means that the film carrier has a problem.This test is used to check if the primary belt is sufficiently tightened. For that, the software measures the current sent to the motor, which reflects the tension on the belt: the more the belt is tightened, the greater the effort needed to turn the motor, the greater the current.
The film advance during the scanning must be as regular as possible. In addition the software regulates the current sent to the motor in relation to the efforts needed. Therefore the current must be as steady as possible, however, variations may occur due to the off centred effect of the gears.
The measurement of the belt tension is taken for both directions of rotation of the motor (corresponding to the pre-scanning and actual scanning).
If the belt is not sufficiently tightened, the film could slip during the scanning and this could lead to a faulty framing of the images. On the other hand, if the belt is too tight, the risk of overtorque (overloaded motor) will increase.
2. Test conditions.
This test relates to the APS film carrier inserted in the scanner.The APS film carrier must be inserted in the scanner to carry out this test.
No film is necessary for this test.
The acceptance of the test is automatic.
No parameter is saved.
3. Pre-requirements.
Before proceeding with this test, it is necessary to mechanically tighten the 2 belts of the film carrier . This is done normally with a adequate tool (comparator), but it can be done by hand.- If the tool is available : remove the protective plate of the film carrier (the belts become visible). Loosen up the lock-nut (1) (at the back of the film carrier). Take out the antiflare plates (2). Place the tool between the lower and higher plate (3), then press on the belt using the comparator. Tighten or slacken the belt while operating the eccentric (4)(behind the lock-nut). When the correct tension is found, tighten the lock-nut (1).
Proceed the same with the other belt. - If the tool is not available : remove the protective plate of the film carrier (the belts become visible). Loosen the lock-nut (1) (at the back of the film carrier). Take out the antiflare plates (2). Tighten or slacken the belt while operating the eccentric (4) (behind the lock-nut) until finding the correct tension. Proceed the same way with the other belt. Tighten the lock-nut (1) and launch the test in order to check that the tension is correct.
4. Test realisation.
Click on RUN to execute the test. The motor will turn during 15 seconds in one direction then 15 seconds in the other (these 15 seconds correspond to one revolution of the film carrier belt.At the end of the test, in the result box, a red curve and one blue curve will be displayed (corresponding to both directions of rotation of the test). In the execution window, the quantified results of each curve will be displayed. The test automatically will be accepted or rejected according to the results of these 2 curves.
5. Acceptation du test.
The software uses mainly 3 criteria (for each direction of rotation, that is to say 6 in total) in order to accept or reject the test :- the average of the curve: must lie between 97 and 119,2.
- the maximum of the curve: must be lower than (real average + 15,5%).
- minimum of the curve: must be higher than (real average - 15,5%).
6. Other affeted tests.
If the tension of the belts of the APS film carrier is modified in significant proportions, the following tests should be redone :- APS cal encoder 2.
- APS cal RGB IR.