Fluke Biomedical 875 Victoreen - Manual (Page 37)

Victoreen 875 High Range Containment Monitor
Operator Manual
5-6
larm circuit (muting stages are treated
separately). Reset the alarm after every test.
TP502 epe th of
int *Normal Channel
U50 -9.8 V +13.7 V
n of R510 and CR501 -9.8 V +1.45 V
) Pin 14 U503 +14.1 V +0.2 V
to light.
The lighting of the CHANNEL TEST lamp does not
ple resistance
5.8 High Alarm Circuit
Troubleshooting in the h larm circuit.
Voltages may be slightly However, the high and
low state should be reco
5.9 Muting Stages of the Alarm Circuits
The muting stages of the alarm circuits (U502 pins 8, 9, 10 and pins 12, 13, 14) can cause trouble in two
ways:
1. They can fail to mute the alarm circuits during the ECS Test, thus causing the alarms to sound
when this is undesired.
2. They can mute the alarms when the alarms should sound. This is the more undesirable of the two
possibilities.
If the CHANNEL TEST lamp lights when the CHANNEL TEST push button is pressed, the second
possibility is eliminated. Conversely, if it does not light, malfunction in the muting stages is among the
problems that must be considered in addition to those in the signal chain (also a light burn-out).
The following are measured voltages at critical points in the alert a
1) 0 to 6 V d nding on streng radiation
Test Po Test
2) Pin 1 2
3) Junctio
4
5) Pin 1 U503 +0.08 V +13.7 V
*Normal here signifies a small radiation signal so that the voltage at TP502 is close to zero volts.
NOTE
Both of the solenoids of the alert and high alarm
circuits must operate for the CHANNEL TEST lamp
of itself show that the remote alarm contacts have
closed (See Relay Driver Schematic, drawing
876A-1-3B.) However, sim
measurements and reference to the relay driver
schematic can assure that the output to the remote
alarms is correct.
igh alarm circuit is completely analogous to that in the alert a
different because R513 may be set differently from R509.
gnizable.