2-17. SELF TEST
When its FUNCTION switch is set to TEST, the local control panel or the remote control unit tests itself and the
interface to the control module. If good, the control module begins the rt self tests. The rt receive path and ECCM
module are then checked.
a. Control Panel or Control Unit Test (FAIL 7 and FAIL 8). The local control panel or remote control unit first
requests a display update from the control module. If a response is made, the control interface is considered
good. If not, FAIL 7 is displayed. Then the control panel or control unit tests its RAM, ROM, and connections to
the front panel switches. If a check fails, FAIL 8 is displayed. Pressing any key after FAIL 8 will display as
If neither FAIL 7 nor FAIL 8 occur, the control panel or control unit signals the control module to begin rt checks.
b. Display Checks. E - should be displayed when FUNCTION is set to TEST if the control test passes. The
control module checks for the presences of the ECCM module. The ECCM module grounds the FH HERE-N line.
See FO-8. If the ECCM module is absent, the letter E is replaced by a dash (-). The next display is 88888. It
checks the display segments.
c. Receive Path Test (FAIL 1). The receive path is tested in three steps. First, the control module performs a
memory check (RAM and ROM). Second, the TONE SQUELCH line is checked with no squelch tone present. (It
should be at logic O). Third, the receive path is checked at eight frequencies in the SC mode and two frequencies
in the FH mode. Squelch tone is included and the test passes if TONE SQUELCH line is at logic 1.
The 150-Hz squelch tone modulates the 3.9 MHz oscillator located in the amplifier-oscillator. The harmonics from
the 3.9 MHz oscillator serve as test frequencies. The control module steps the synthesizer through the test
frequencies. Because the tuner/mixer and synthesizer have several bands, it is possible that only one or two
frequencies will fail.
There are secondary displays for each failed test. They will be displayed when a keyboard button is pressed as
the FUNCTION switch is set to TEST. They are:
Control module RAM
Control module ROM
Receive at 30.0 MHz, SC (no tone)
Receive at 78.0 MHz, SC (tone)
Receive at 66.3 MHz, SC (tone)
Receive at 58.5 MHz, SC (tone)
Receive at 50.7 MHz, SC (tone)
Receive at 46.8 MHz, SC (tone)
Receive at 39.0 MHz, SC (tone)
Receive at 35.1 MHz, SC (tone)
Receive at 31.2 MHz, SC (tone)
Receive at 35.1 MHz, FH (tone)
Receive at 78.0 MHz, FH (tone)
The audio present during the 88888 display is a result of the receive tests. There will be 10 short bursts of
unsquelched rushing noise. However, because they are so quick and close together, they are difficult to count.
d. ECCM module (FAIL 3). The ECCM module also performs an independent self-test. It checks its RAM,
ROM, interleave, linear sequence generator, and other circuits. If it does not pass, FAIL 3 is displayed. The
beep heard at the end of 88888 display indicates the presence of ECCM module.
ECCM ROM #l
ECCM RAM #2
Linear Sequence Gen.
Non-Vol. Memory Protect