HF Series Generators
T roubleshooting
TR-1005R4
44
ERROR CODE : E12
DESCRIPTION : No mA during exposure or mA out of tolerance. Wrong filament current.
ERROR TYPE : Informative.
APPLICABLE TO : All Generators
APPEARS WHEN : After exposition.
INFORMATION / SYMPTOM : Error 12 appears after the Exposure to alert the operator that the mA at the starting of the exposure has
not been correct. During the first 10 ms the Generator applies constant filament current to the tube.
This current is proportional to the current already calibrated for that mA station at the kVp selected for
that Exposure (filament numbers). Near the end of these 10 ms, the HT Controller reads the mA and if
they are found to be a 30% under or over of what has been selected, it sends error 12 to the Console.
POSIBLE CAUSES
Calibration data for kVp and mA that produces E12 are not correct.
The mA jumper on the HV T ransformer is open, or it is not making good contact. The mA read at the
beginning of the exposure is 50% of the correct value (because one branch is open).
There is a problem on the reading of the mA.
No correct heating prior to the Exposure. The filament has not reached its correct temperature and
the mA at the starting of the exposure is low. It usually occurs when the “Prep” and “Exp” buttons are
pressed down at the same time.
Making an exposure immediately after getting out of calibration mode in extended memory .
+5 VDC , +12 VDC or --12 VDC Power Supplies of HT Control Board (mesured at TP2, TP3 and TP4
of this Board) have excesive ripple or VDC measured is not correct.
ACTIONS
1. Connect a scope to the following Test Points in the HT Control Board and check that the voltage
is correct, if not adjust it with the respective Potentiometer in the Power Supply Board (refer to
Section 2.1 -- Low DC Voltage Power Supply Test):
TP2 (+5 VDC) in HT Control Board is adjusted with R12 Pot. in the Power Supply Board.
TP3 (+12 VDC) in HT Control Board is adjusted with R26 Pot. in the Power Supply Board.
TP4 (--12 VDC) in HT Control Board is adjusted with R25 Pot. in the Power Supply Board.
2. Check calibration data for the mA Open Loop (filament numbers) as stated in the Service Manual
for all combination of kVp and mA when this error appears.
With a scope connected to the Test Point TP5 (mA) in the HT Control Board check that the mA
read is within the ratio of 1V=100 mA (± 5%) for V2 and V3 software versions, for V4 and up the
ratio is 1V=10mA from minimum mA to 80 mA and 1V=100mA from 100 mA to the maximum
rating. If it is not, the cause could be that the mA second test is not measuring right, or a wrong
measurement performed in the Generator. (Refer to step 3).
3. Check that the jumper in the mA test point of the HV Transformer is well placed and tighten.
4. With a scope check that during the entire Exposure signals on the test point TP13 (--mA) and
TP14 (+mA) on the HT Control Board connectors are symmetrical (± 10%). If one is found
missing or not symmetrical, measure on pin 6 and 7 of J4 on the HT Control Board. If they are
symmetrical on both points, the problem could be in the HT Control Board. If they are not correct,
check that the connections made on the HV T ransformer in J1-E, D, K terminals for Compact
Generators (in TB1, terminals 1, 4 and 5 for no Compact Generators) are well connected and
tighten. Also check that the GND wire is connected to the GND stud. If connections are correct
the problem is in the HV Transformer.
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