Pulsar TC-10B, User Manual

Page: 130 / 190

Optical isolators U1 and U2 turn on together and
share the following characteristics:
Isolation voltage: 7,500Vdc
Transistor rating: 400Vdc
The input from A-26 and A-28 energizes both
optical isolators (U1 and U2). This initiates the
circuit flow for both of the module’s outputs. As
described below, the two output circuits are
virtually the same.
OUTPUT #1 Circuit Flow
The output from optical isolator U1 drives tran-
sistor Q1 to the ON state, which in turn drives
transistor Q3 to the ON state. Transistor Q3
provides a 1A output on A-14 and C-14 and a
20mA/200mA output on A-16 and C-16, with the
station battery tied to A-12 and C-12.
Resistor R2, capacitor C1, and metal oxide
varistors M02 and M03 provide circuit protection
against surges coming in from the outside world.
Diode D1 provides reverse voltage protection —
in case the outputs are connected backwards.
OUTPUT #2 Circuit Flow
The output from optical isolator U2 drives tran-
sistor Q2 to the ON state, which in turn drives
transistor Q4 to the ON state. Transistor Q4
provides a 1A output on C-20 and a 20mA/
200mA output on A-22 and C-22, with the station
battery tied to C-18.
Resistor R1, capacitor C2, and metal oxide
varistors M01 and M04 provide circuit protection
against surges coming in from the outside world.
Diode D2 provides reverse voltage protection —
in case the outputs are connected backwards.
15.3 Troubleshooting
You can ensure the Receiver Output Module is
getting the proper input from the Receiver/AM
Detector module(s) by using the “Input Test”
procedure described here. To make sure the
module’s outputs are correct, use the “Output
Tests” procedure. To isolate and check faulty
components, you can use your normal trou-
bleshooting techniques.
15.3.1 Input Test
Use this procedure to verify that the Receiver
Output Module is getting the proper input from
the Receiver/AM Detector module(s). You will
need the following:
• Extender board
• Digital volt meter
Preliminary Steps
1. Connect a power supply source (48, 125, or
250Vdc) to the following rear panel terminals
attached to the Receiver Output Module (with
reference to TB7-2):
• OUTPUT #1: TB1-1 (+)
• OUTPUT #2: TB1-4 (+)
2. Place the Receiver Output Module on an
extender board (see Figure 4-1).
3. Connect the digital volt meter to pins A/C-26
(+) and C-28 (–).
Input Test Procedure
Check the input coming from the Receiver/AM
Detector module(s) at pins A/C-26 (+) and C-28
(–); potential voltage should be +10Vdc.
1. Using the digital volt meter, measure the
voltage level at pins A/C-26 (+) and C-28 (–).
The potential voltage should be +10Vdc.
2. Disconnect the digital volt meter.
3. Re-install the Receiver Output Module.
Page 15–4 October 2003
TC–10B System Manual
Technologies, Inc.