Villa Rotograph EVO, Service Manual

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SERVICE MANUAL
Maintenance and servicing
Rotograph EVO (Rev. 1) 7-18
7.3.2. mA Check
Use a multimeter (R input >= 10M
Ω ) in working conditions VDC and end
of scale 5/10 V (maximum value 4VDC), position the cold pole on TP40
(GND) and the hot pole on TP29 (mA). Set the following parameters:
60kV-6mA-3s.
Perform an exposure and considering that a ratio 1V DC
≈ 3 mA, verify
that the value indicated by the multimeter ranges from 1.86 ÷ 2.138V
(6mA±8%).
Set 80kV - 12mA - 3s. The value read must range from 3.643 to 4.276 V
(12mA±8%).
Measured valued for different set values are contained on the following
table.
mA Nominal
value
Minimum
value
Maximum
value
6 1.98 1.822 2.138
7 2.31 2.125 2.495
8 2.64 2.429 2.851
9 2.97 2.732 3.208
10 3.30 3.036 3.564
11 3.63 3.340 3.920
12 3.96 3.643 4.277
In case the detected values are outside these ranges, check that the
voltage between TP40 (GND) and TP34 (ma) is contained on the above
ranges. If not, replace the Generator CPU board (A9).
7.3.3. Time
Verify the accuracy of the exposure time using an oscilloscope connected
at the same test points used to measure mA (TP40 for GND and TP29
mA) of the Generator board (A10). The exposure time calculated at about
75% of the maximum kV value, must correspond to the set one +10%. In
case the time is outside the prescribed values, replace the CPU.