Fluke Biomedical 875 Victoreen - Manual (Page 35)

Victoreen 875 High Range Containment Monitor
Operator Manual
5-4
NOTE
876A-1 by removing cables from J1 and J2 before
alarms as well. It is the responsibility of the user to
t the alarms are not set off by disconnection.
5.4 Power Supply Measurements (P/N 876-1-89 Schematic 876-1-3C)
urn the 876A-1 on by turning the function switch to the ALL position.
CAUTION
Allow all equipment, including the readout module,
f the black expanded arc to within 0.50 needle width.
1. Connect the negative lead of the DMM to T
2. Probe TP101 with VDC.
Power Supply Printed
3. Probe TP5 (white) .
4. Probe TP4 with th MM should read -10.00
± 0.01 VDC. Adjust R4 as
st R5 as required to
achieve correct readings.
±
1-
relay driver board. It consists
oard) and amplifier U501
(relay driver board). The output of U501 provides the input for the meter circuit on the preamplifier meter
board and the high and alert alarm circuits on the relay driver board. The alarm circuits are covered in the
"Alarm Circuits" paragraph. The signal input circuit can be tested at two test points, using the CHANNEL
Disconnect Detector 877-1 from Readout Module
starting troubleshooting of readout module. The
user will probably wish to disconnect the external
see tha
T
to warm up for at least 60 minutes before
attempting any calibration.
Adjust the mechanical zero of the panel meter (use mirror scale to avoid parallax error) so that the needle
is centered on the first hash mark o
Verify the output voltage of the power supplies as follows (See drawings 876-1-78 and 876-1-89).
Mother Board (P/N 876-1-78, Schematic 876-1-3A)
P102.
the positive lead of the DMM. The DMM should read +24
± 3
Circuit Board (P/N 876-1-89, Schematic 876-1-3C)
with the positive lead. The DMM should read -21
± 2 VDC
e positive lead. The D
necessary to correct this reading.
5. Probe TP2 with the positive lead. The DMM should read + 15.0
± 0.2 VDC. Adju
6. Probe TP3 with the positive lead. The DMM should read +14.3
± 0.4 VDC.
PreamplifierIMeter Board (P/N 876A-1-86, Schematic 876A-1-3E)
7. Probe TP401 on preamplifier meter board with the positive lead. The DMM should read +6.200
0.001 VDC. Adjust R413 as necessary to correct this reading.
Rear Panel
8. Probe the back panel high voltage connector, J2. The DMM should read +506
± 10 VDC.
5.5 Signal Input Circuit
(P/N 876A-1-35, Schematic 876A-1-92 & P/N 876A-1-75A, Schematic 876A-
3B)
The signal input circuit is partly on the preamplifier board, and partly on the
of logarithmic amplifier U301 and its associated circuitry (preamplifier meter b