Villa Rotograph EVO, Service Manual

Page: 150 / 223

SERVICE MANUAL
Troubleshooting
(Rev. 1) Rotograph EVO 8-59
•
Exposure parameters not correct
–
Check the correctness of the exposure parameters using the
procedure described on paragraph 7.3.
–
If the measured value of the feedback signals coming from the
tubehead are correct, a possible fault of the tubehead itself has
occurred, so replace the tubehead.
–
If the feedback measured values are not in the specified range,
check the correctness of the set value, using a digital meter
having at least 10 M
Ω input resistance and set it for VDC
measure with a 20V full scale reading.
1. Power off the machine and connect the ground cable to Test
Point TPGNGD and the sensing pod to test point kVset.
2. Power on the machine and, using password 118, primary
collimator menu, perform an exposure using 60 kV and a
time of 1s.
3. Check that the set value during exposure is 3 V ± 0.2V.
4. Repeat the test selecting 70 and 80 kV; the reading should be
3.5 and 4 V
±
0.2V, respectively.
5. If test fails, repeat the test connecting the meter to the CPU
test points; see description below.
6. If all tests pass, check tube current, connecting the sensing
pod to mAset.
7. Set mA to 4 mA and perform an exposure and read the value
that must be 2V
± 0.2V.
8. Repeat the test for 6, 8 and 10 mA; the measured value
should be 3, 4 and 5 V, always with the same accuracy.
9. If the test pass, repeat the tests attaching the meter to the
CPU.
10. If the test fails, check the cable X4 (HF) – X9 (CPU); if broken,
replace the cable.
11. Check of set point at the CPU side; disconnect the meter from
HF power board and connect it to CPU board; ground to
TPGROUND sense pod to KVSET. Repeat the exposure above,
checking both kV and mA.
12. If the measured values for set points at the CPU are not
correct, replace the CPU; otherwise replace the tubehead.