OPERATING PROCEDURES.

TM 11-6660-266-13

(b) Verify that 24 VDC Power Supply AC IN and DC OUT LEDs illuminate. lf LEDs do not illuminate, refer

(c) At power-up, verify that CDU automatically initiates self test.

(2) CDU Self Test

NOTE

During the power-up sequence, a handshake occurs between the RDF Unit

and the CDU. lf the CDU is disconnected after power-up, the entire RDF

Unit power-up sequence must be repeated to re-establish the handshake.

At powerup, the CDU automatically initiates self test. During the self test routine, the cursor will flash at

the lower left comer of the display screen. After successful completion of self test, the RDF operating

screens are displayed. If any of the CDU self tests fail, an error message is displayed. The CDU performs

five self tests at power-up to verify integrity. No keys should be depressed during self test, otherwise an

error message will be displayed.

(a) Keyboard Test. The CDU checks the keyboard for any closed contacts. If a closure is detected, it is

indicated in the display and operation of the CDU stops. The cursor will not appear.

(b) CPU Test- The CPU registers and flags are tested. If a failure is detected, it is indicated in the display

and operation of the CDU stops. The cursor will not appear.

(c) ROM Test. A sixteen bit checksum is performed on all locations of the program memory. This result is

then compared to a stored checksum. If a failure is detected, it is indicated in the display and operation of

the CDU stops. The cursor will not appear.

(d) RAM Test. Each of the 128 bytes of internal microprocessor RAM and 2K bytes of external RAM is

checked for dropped bits, hung bits, or adjacent shorts. lf a failure is detected, it is indicated in the display

and operation of the CDU stops. The cursor will not appear.

(e) Interface Test. At power-up, the CDU disconnects the interface drivers from the internal UART and

loops back internal data and handshake lines to verify proper operation.

(3) Perform RDF Unit self test in accordance with TM 11-6660-281-12.

2-5-4. Align RDF Unit. Align the RDF Unit in accordance with TM 11-8880-281-12.

2-6. OPERATING PROCEDURES.

To operate the AN/TMQ-38 to provide field users (subscribers) with current weather (MET) data, the following 4

major steps must be performed:

Initialize the MARWIN Processor

Initialize the DCT

Perform NAVAID or RDF sounding

Transmit MET messages

For a description of operator controls for the AN/TMQ-38, refer to Chapter 2, Section I.

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