Fluke Biomedical 956A-201-M2 - Manual (Page 81)

5-3
Test Procedure, 955A-XXYYZ System
Check Source Response
1. Depress and hold the Check Source pushbutton for approximately two (2) minutes. Record the
average mR/h value displayed. The value displayed will normally be within
± 25% of the value
recorded on the factory data sheet. For slightly more precise data, subtract the ambient background
value from the gross check source value.
2. Verify the following conditions are met for proper check source operation:
a. Properly connected detector to 956A-201 UDR
b. +15 Vdc power is present from the 956A-201 UDR
c. Proper discriminator adjustment in the 956A-201 UDR
d. Proper G-M tube high voltage is supplied from the 956A-201 UDR
e. Fully functional detector preamplifier (located within the detector outer housing)
f. Fully functional G-M tube (located within the G-M detector housing)
Item (a) may be verified by physical inspection of the detector to
956A-201 UDR interconnecting cable.
Items (b - d) may be verified by the 956A-201 UDR readout tests
provided herein.
Items (e - f) require return of the detector assembly to Cardinal
Health, Radiation Management Services for repair and
recalibration.
3. For ALARA considerations, disassembly of the detector to observe, or attempt to correct check
source operation is not recommended. There are no user serviceable parts on the check source
mechanism.
DC Voltage Checks, 956A-201 UDR
1. Using a digital voltmeter set to read DC volts, measure the voltages listed in Table 5-1
Table 5-1. DC Voltage Test Points
Test Point DC Power Supply Voltages Potentiometer
TB-1 -15 Vdc, ± 0.75 V N/A
TB-2 Ground DC N/A
TB-3 Ground DC N/A
*TB-4 + 5.0 Vdc, ± 0.10 V VR1 (or power supply)
TB-5 + 15 Vdc, ± 0.75 V N/A
* The only adjustable voltage is the +5.0 Vdc supply. The other voltages are regulated by the +5.0 Vdc
supply. If the +5.0 Vdc supply is out of tolerance, adjust VR 1 on the power supply
NOTE