Siemens-Elema AB
SPS-UD
RX B7-120.033.01.10.02
MAMMOMAT 300
Solna, Sweden
05.98
65 02 186
11-2
Checks with high voltage
3
Connect oscilloscope to p.c. board D705 as follows:
•
Channel 1 to measuring point "KVIST
(actual value)
" (1 V= 5 kV).
•
Channel 2 to measuring point "MAIST
(actual value)
" (1 V= 40 mA).
•
Trigger at measuring point "KVE" (start with high voltage "ON"), rising edge.
•
Twist the measuring leads and connect their grounding braids to measuring point
"0VA".
4
Connect service PC to circuit board D702 using the connection cable.
NOTE!
Switch S3 on circuit board D702 must be set to upper position.
5
Start service program, see section 21 "Appendix".
Checking X-ray tube high voltage, tube currrent and mAs
values
1
System "ON".
2
Set the "cassette loaded" switch to "0" with the service PC program: Stand configu-
ration - Stand installation - Cassette loaded check (0=function deactivated).
3
Trigger test exposures with the following exposure values and check the kV values
and tube current characteristic on the oscilloscope (se oscillograms).
The accuracy of the kV is +/- 5% plus +/- 1.5 kV during the first 5 ms of the exposure.
For mA values < 50 mA, the accuracy of the kV is +/- 5% plus +/- 2 kV during the
first 5 ms.
The tube current must rise quickly to set value at the beginning of the exposure and
run linearly during the exposure, however not when TCR is running.
The accuracy of the mAs product must be +/- 10%.
4
Replace the jumper previously removed.
Tube current reduction
NOTE!
In MAMMOMAT 300, the tube current reduction is factory set to "ON" (see section 13
and test certificate). In this way, the tube current is reduced to approximately 50 mA at
the start of the exposure during the time programmed in section 13.