Raytheon ST60, Service Manual

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Part 1. ST60 Instruments – Chapter 3. Multi
A22003
18 ST60 Instruments Service Manual 83142-1
No fail codes are generated since stage 2 is an audio/visual check. The following can,
however, be used as a guide to isolate a problem:
Failure Mode Action
No illumination Check TR14, TR13, TR15 and associated components.
Check all LEDs.
Keypad Illumination failure Check TR14, TR13, R22 and R23.
(LCD illumination will also be degraded) Check LED1-6 for open circuit.
Keypad illumination OK Check TR14, TR15, RN3, R24.
but degraded LCD illumination Check LED 7 and 8 for open circuit.
No beep when key pressed Replace keyswitch.
LCD segment(s) missing completely Check LCD solder pins for poor/dry joints.
Check IC3 for unsoldered pins.
Faint LCD segments Check LCD pins for shorts.
Check IC3 for shorts.
Press Key 1 and Key 2 together momentarily to progress to exit self-test (stages 3
and 4 are not supported on this instrument).
NMEA I/O Testing
Note that there is no self-test for NMEA input/output. As a guidline, if NMEA has
failed, do the following:
1. Ensure that NMEA output has been turned ON in user CAL.
2. Ensure that the instrument is receiving seatalk data for translation to NMEA (e.g.
Heading, Latitude, Longitude etc...)
3. Voltage at N should be approx 11.2v with 12v battery supply.
Current supplied from this pin to BATT- should limit at approx.80mA. If there is
a problem with this supply, check TR18, TR19 and associated components.
4. Connect a dummy load (1K resistor) across N and NMEA_OUT-
and check for pulses at NMEA_OUT- If no pulses are seen, check R18 and TR5.
5. Disconnect dummy load and connect NMEA outputs to corresponding NMEA
inputs. Check for pulses at the junction of R59 and R60 (TP192). If no pulses are
seen, check R55-58, L7 and IC8.
6. Check the final stage output at TR4b (TP116)