**The following is a set of ATCBI-6 System related troubleshooting
comments and suggestions that have been compiled by Raytheon ATCBI-6
Program Installation and Test Team personnel. These comments are
intended to supplement the guidance and technical data provided in the
ATCBI-6 System Manual.**

**This is intended to be a working document. Your comments, suggestions
and particularly additions are welcome.**

**Introductory Comments:**

**A. Fault Isolation:**

1.  **Swapping LRUs between Channels:**

If time is available and site operations conditions permit, it would be
desirable to swap an apparently failed Line Replaceable Unit (LRU) from
one Interrogator channel to the other to determine whether or not the
fault follows the LRU. If the fault switches from one interrogator to
the other with the LRU, then that may confirm the isolation of the
fault.

2.  **Changing Multiple LRUs**

If multiple replacement LRUs have been requisitioned and received, it
would be beneficial if each LRU replacement can be separately tested /
retested and the fault isolated at the site. If the first replacement
LRU does not resolve the system fault, then the original LRU should be
reinstalled and then another LRU replaced. Swapping multiple LRUs into
the system between channels and then testing the system may be tedious
but this effort is worthwhile if a system fault can be isolated to one
item.

3.  Electrostatic Discharge Control ("ESD")

Please use proper Electrostatic Discharge Control ("ESD") precautions,
equipment and procedures when handling ATCBI-6 system LRUs. Treat all
LRUs as ESD sensitive.

4.  Check for the Simple Causes:

If there has been some maintenance activity at the site and a new
ATCBI-6 system alarm or fault is observed, please check for simple
possible causes such as power supply, fuses, loose connectors, failed
indicator light bulbs, or LEDs.

B. Reporting Faults with Returned LRUs:

The LRUs that are returned from the sites as failed units will be
evaluated, tested and repaired as required.

Please note that the efficiency of the work performed by the test,
evaluation and repair personnel can be enhanced if failure mode
information is returned with any failed item. When any replacement items
are returned to the Depot Operation, please include information that
identifies: the site, the date, the name of the individual who returned
the item; the alarm message that was recorded, the time of the failure,
the nature of the failure (e.g. was the failure intermittent? over what
period? identify LMT Fault Isolation Display message) etc.

The standard shipping documentation for replacement LRUs includes a
Block #26 where this information should be entered for return with the
LRU. If a replacement item was used only for troubleshooting or was not
opened and/ or installed, then please note that status on the return
shipping documentation.

Any and all failure mode information that can be returned with an item
will aid the test, evaluation and repair process and will also be
tracked to determine whether any trend of failures exists.

As of the date of this correspondence, there are no trends of failures
for any part of the ATCBI-6 system.

+--------------+----------------------------+--------------------------+
| # Failed LRU | **Symptom**                | **Solution**             |
+--------------+----------------------------+--------------------------+
| Low Duty     | +52V power supply          | Replace LRU, return      |
| Power        | indicates +1V.             | failed unit with fault   |
| Amplifier    |                            | description              |
|              |                            |                          |
| 808125/004   |                            |                          |
+--------------+----------------------------+--------------------------+
| Low Duty     | The CMS log reported the   | Replace LRU, return      |
| Power        | following:                 | failed unit with fault   |
| Amplifier    |                            | description              |
|              | \[S\] 17:48:52             |                          |
| 808125/004   | ATCBI6:As:Control Reg.     |                          |
|              | Limit Exceeded             |                          |
|              |                            |                          |
|              | \[S\] 17:48:52             |                          |
|              | ATCBI6:As:Fault On Tx/Rx   |                          |
|              | Control & BITE,RX/PE       |                          |
|              | Assembly,807893            |                          |
|              |                            |                          |
|              | \[S\] 17:48:52             |                          |
|              | ATCBI6:As:Fault On LDPA,TX |                          |
|              | Assembly,808125            |                          |
|              |                            |                          |
|              | \[S\] 17:48:52             |                          |
|              | ATCBI6:As:Control Reg.     |                          |
|              | Limit Not Exceeded         |                          |
|              |                            |                          |
|              | \[S\] 17:48:52             |                          |
|              | ATCBI6:As:Fault Cleared on |                          |
|              | Tx/Rx Control & BITE,RX/PE |                          |
|              | Assembly,807893            |                          |
|              |                            |                          |
|              | \[S\] 17:48:52             |                          |
|              | ATCBI6:As:Fault Cleared on |                          |
|              | LDPA,TX Assembly,808125    |                          |
|              |                            |                          |
|              | ## Swapping the C          |                          |
|              | h A LDPA to Ch B ran for 4 |                          |
|              |  days without faults, but  |                          |
|              | when returned to Ch A faul |                          |
|              | ts appeared again. It does |                          |
|              |  not cause a Channel swap. |                          |
|              |                            |                          |
|              | Checked the 52V supply on  |                          |
|              | both channels Ch A 52.11v  |                          |
|              | Ch B 52.15v                |                          |
+--------------+----------------------------+--------------------------+
| Low Duty     | While conducting the SAT   | Replace LRU, return      |
| Power        | Subset 1 para 2.3.1 (a)    | failed unit with fault   |
| Amplifier    | "Ensure Sum and Control    | description              |
|              | attenuation are set to     |                          |
| 808125/004   | minimum. (i) measure the   |                          |
|              | peak power of the P2 pulse |                          |
|              | and confirm that it is     |                          |
|              | greater than 31.5 dbW" .   |                          |
|              | On Interrogator "A" with   |                          |
|              | the attenuator at minimum  |                          |
|              | I only had 31.6 dbW would  |                          |
|              | not go any higher. By      |                          |
|              | Swapping the LDPA with "B" |                          |
|              | the power came up to 32.7  |                          |
|              | dbW and was adjustable. By |                          |
|              | Putting the LDPA in "B"    |                          |
|              | the problem followed (low  |                          |
|              | nonadjustable control      |                          |
|              | power).                    |                          |
+--------------+----------------------------+--------------------------+
| Low Duty     | The problem was noted      | Replace LRU, return      |
| Power        | while conducting SAT       | failed unit with fault   |
| Amplifier    | procedure Subset 1 para    | description              |
|              | 2.3.1 (p), on "B"          |                          |
| 808125/004   | interrogator, checking MIP |                          |
|              | 1-16 to ensure P1 & P2 are |                          |
|              | present. When a SAs or SA  |                          |
|              | MIP were turned on, the    |                          |
|              | interrogator shut down,    |                          |
|              | while "A" worked fine. The |                          |
|              | previous step had you turn |                          |
|              | the IISLS (Improved Side   |                          |
|              | Lobe Suppression) on and   |                          |
|              | make changes in the        |                          |
|              | transparent mode (DP16     |                          |
|              | 17=FFFF & DP16 18=FFFF).   |                          |
|              | The system works fine      |                          |
|              | except when this set of    |                          |
|              | things happens together.   |                          |
|              | The LDPA were swapped      |                          |
|              | between channels and the   |                          |
|              | problem followed.          |                          |
+--------------+----------------------------+--------------------------+
| High Power   | +52V power supply          | Replace LRU, return      |
| Amplifier    | indicates +1V.             | failed unit with fault   |
|              |                            | description              |
| 807887/003   |                            |                          |
+--------------+----------------------------+--------------------------+
| High Power   | Channel failed. System     | Replace LRU, return      |
| Amplifier    | fault log showed SUM HPA   | failed unit with fault   |
|              | Output failure.            | description              |
| 807887/003   |                            |                          |
+--------------+----------------------------+--------------------------+
| Driver       | The CMS log reported the   | Replace LRU, return      |
| Module       | following:                 | failed unit with fault   |
|              |                            | description              |
| 807888/004   | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Driver Phase Loop      |                          |
|              | Unlocked                   |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Control Driver Failed  |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Sum Driver Failed      |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Control HPA Output     |                          |
|              | Failed                     |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Sum HPA Output Failed  |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Control TX Low True    |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:SIF Pulse Width Failed |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Diff RX Loc Osc Not    |                          |
|              | Present                    |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Ctrl RX Loc Osc Not    |                          |
|              | Present                    |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Sum RX Loc Osc Not     |                          |
|              | Present                    |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Diff RX 3db Low True   |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Ctrl RX 3db Low True   |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Sum RX 3db Low True    |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Ctrl Output Power      |                          |
|              | Alert                      |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Channel Failed         |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Fault On High Power    |                          |
|              | Amplifier,TX               |                          |
|              | Assembly,807887            |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Fault On Driver,TX     |                          |
|              | Assembly,807888            |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Fault On Tx/Rx Control |                          |
|              | & BITE,RX/PE               |                          |
|              | Assembly,807893            |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :As:Opposite Chan C&B I/P  |                          |
|              | Failed                     |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Sum TX Low True        |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Phase Detector Board   |                          |
|              | Failed                     |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Sum Output Power Alert |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Fault Cleared on High  |                          |
|              | Power Amplifier,TX         |                          |
|              | Assembly,807887            |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Fault Cleared on Tx/Rx |                          |
|              | Control & BITE,RX/PE       |                          |
|              | Assembly,807893            |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Sum TX Rvrs Power      |                          |
|              | Alert                      |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Tx Rvrs Pwr High, Sum  |                          |
|              | Failed                     |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Fault On Tx Interface  |                          |
|              | Assembly,Tx                |                          |
|              | Assembly,807890            |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Fault On Tx/Rx Control |                          |
|              | & BITE,RX/PE               |                          |
|              | Assembly,807893            |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Ctrl TX Rvrs Power     |                          |
|              | Alert                      |                          |
|              |                            |                          |
|              | \[S\] 23:27:42 ATCBI6      |                          |
|              | :Br:Tx Rvrs Pwr High,      |                          |
|              | Cntrl Failed               |                          |
+--------------+----------------------------+--------------------------+
| Driver       | Driver Module 807888/004   | Replace LRU, return      |
| Module       | has a phase loop fault.    | failed unit with fault   |
|              | The LMT and CMS log are    | description              |
| 807888/004   | reporting a Phase Loop     |                          |
|              | Fault and the interrogator |                          |
|              | keeps faulting.            |                          |
|              |                            |                          |
|              | This item does not go      |                          |
|              | directly into alarm, it    |                          |
|              | may take up to two hours   |                          |
|              | to show the PLL            |                          |
|              | error/fault.               |                          |
+--------------+----------------------------+--------------------------+
| Driver       | Driver Module 807888/004   | Replace LRU, return      |
| Module       | has a bad port. The Sum    | failed unit with fault   |
|              | channel output power was a | description              |
| 807888/004   | --18dbw, should be 32 dbw. |                          |
|              | The reverse power was      |                          |
|              | --21dbw should be 0 dbw.   |                          |
|              | The Driver module          |                          |
|              | 807888/004 was swapped and |                          |
|              | the problem followed. The  |                          |
|              | driver module has two      |                          |
|              | paths one for Sum and the  |                          |
|              | other Control. The Sum     |                          |
|              | path is bad.               |                          |
+--------------+----------------------------+--------------------------+
| TX Interface | There is no adjustment     | Replace LRU, return      |
| Assembly     | using "Sensitivity         | failed unit with fault   |
|              | Adjustment" to get it to   | description              |
| 807890/011   | 83+-.02 dbm or when going  |                          |
|              | into the transparent mode  |                          |
|              | with TOFF and PRON you     |                          |
|              | don't get any replies      |                          |
|              | back, so you can't get an  |                          |
|              | SVA value or SDR as        |                          |
|              | required to adjust it.     |                          |
+--------------+----------------------------+--------------------------+
| TX Interface | The CMS control power      | Replace LRU, return      |
| Assembly     | monitor output displays    | failed unit with fault   |
|              | --9dBW, when power meter   | description              |
| 807890/011   | displays 31.5 dBW. No      |                          |
|              | power offsets were entered |                          |
|              | for this channel.          |                          |
+--------------+----------------------------+--------------------------+
| Receiver     | When channel was off-line, | Replace LRU, return      |
| Module       | test target errors         | failed unit with fault   |
|              | occurred.                  | description              |
| 807891/001   |                            |                          |
+--------------+----------------------------+--------------------------+
| Mode S Mode  | No Mode S targets on       | Replace LRU, return      |
| Generator    | either WRTADS CD2/ASTRIX   | failed unit with fault   |
|              |                            | description              |
| 808152/001   | Receives ATCRBS targets.   |                          |
+--------------+----------------------------+--------------------------+
| Control and  | The 65 volt reading on the | Replace LRU, return      |
| BIT PEC      | LMT is zero (0), but after | failed unit with fault   |
|              | trouble shooting the       | description              |
| 807893/002   | wiring and verifying the   |                          |
|              | voltage at each point      |                          |
|              | along the path, it was     |                          |
|              | determined that the 65     |                          |
|              | volts was present.         |                          |
|              | Inhibiting test 188 causes |                          |
|              | the system to function     |                          |
|              | normally.                  |                          |
+--------------+----------------------------+--------------------------+
| Plot         | Unable to boot-up Built In | Replace Plot Extractor   |
| Extractor    | Self Test (BIST)           | (refer to the separately |
| Processor    |                            | issued Plot Extractor    |
| PEC          |                            | Programming Guide)       |
|              |                            |                          |
| 808365/001   |                            |                          |
+--------------+----------------------------+--------------------------+
| Plot         | During the SAT subset 3    | Replace Plot Extractor   |
| Extractor    | Para 4.3.3.4 RSCT          | (refer to the separately |
| Processor    | Interface check, the       | issued Plot Extractor    |
| PEC          | received numbers jump way  | Programming Guide)       |
|              | up and the Non-Octet       |                          |
| 808365/001   | errors go up greatly.      |                          |
|              | Reloading the plot         |                          |
|              | extractor software didn't  |                          |
|              | make any difference.       |                          |
+--------------+----------------------------+--------------------------+
| Transmitter  | LMT TX monitor +52V        | To quickly isolate the   |
| Power Supply | indicates +1V.             | problem, power off the   |
|              |                            | interrogator and         |
| 917771/002   | Fault Isolation will show  | disconnect the cables    |
|              | several items.             | from the LDPA 808125/004 |
|              |                            | and the HPA 807887/003.  |
|              |                            | Loosen their fixing      |
|              |                            | screws and slide each    |
|              |                            | module out approx one    |
|              |                            | inch. Power up the       |
|              |                            | interrogator and see if  |
|              |                            | the 52V supply is now    |
|              |                            | reading 52V. If the TX   |
|              |                            | monitor indicates +52V,  |
|              |                            | then one of the modules  |
|              |                            | has failed. If it still  |
|              |                            | reads +1V the power      |
|              |                            | supply has failed. Power |
|              |                            | off the interrogator.    |
|              |                            | Re-insert and re-connect |
|              |                            | the LDPA. Power up the   |
|              |                            | interrogator. Check the  |
|              |                            | TX Monitor again and see |
|              |                            | if it is +52V. If it     |
|              |                            | reads 52V, the HPA has   |
|              |                            | failed. If it reads +1V  |
|              |                            | the LDPA has failed.     |
+--------------+----------------------------+--------------------------+
| Multi-Output | Interrogator A changed     | Replace Multi-Output     |
| Power Supply | channels and quit. The     | Power Supply             |
|              | only LEDs that are lit are |                          |
| 808315/001   | the Power available (LP2   |                          |
|              | amber) and Power ON (LP1   |                          |
|              | green), the LEDs on the    |                          |
|              | Fan Fail PEC 808364/002    |                          |
|              | are not lit (not showing   |                          |
|              | voltage) the --70V, 65V    |                          |
|              | are missing, and the FANS  |                          |
|              | don't turn. There is 52V   |                          |
|              | on the PSU1 917771/002.    |                          |
|              | The Fault isolation shows; |                          |
|              | Multi Rail Power Supply,   |                          |
|              | Fan Fail Pec, Plot         |                          |
|              | Extractor, Site Service.   |                          |
|              | Rack Status showing        |                          |
|              | nothing.                   |                          |
+--------------+----------------------------+--------------------------+
| Fan Fail PEC | Interrogator "B" was       | Replace LRU, return      |
|              | offline and dead, it was   | failed unit with fault   |
| 808364/002   | noted that the +15V and    | description              |
|              | +12V LEDS were not lit.    |                          |
|              | After checking the fuses   |                          |
|              | it was found that FS7 (3A) |                          |
|              | fuse was blown, after      |                          |
|              | replacement there was      |                          |
|              | smoke. Future              |                          |
|              | investigation found that   |                          |
|              | R84 & R41 on the Fan Fail  |                          |
|              | PEC were burnt.            |                          |
+--------------+----------------------------+--------------------------+
| Microwave    | Bad control coupler,       | Replace LRU, return      |
| coupler      | reverse power low. It was  | failed unit with fault   |
| L            | found that the forward     | description              |
| K1063648300C | power is correct, but the  |                          |
|              | reverse power was at a     |                          |
|              | level of -14.7 and would   |                          |
|              | not go into alarm. Spare   |                          |
|              | microwave coupler was      |                          |
|              | installed and the level    |                          |
|              | went to a --30.1which is   |                          |
|              | normal.                    |                          |
+--------------+----------------------------+--------------------------+
| Microwave    | Found Ch A Sum Output      | Replace LRU, return      |
| coupler      | Power reading 31.4 dBW     | failed unit with fault   |
| L            | with the 4500A RF Test     | description              |
| K1063648300C | Set. Power on LMT still    |                          |
|              | indicated 32 dBW.          |                          |
+--------------+----------------------------+--------------------------+
| Azimuth      | No power indication on the | Replaced 28V fuse        |
| Encoder      | channel A AES. Checked     |                          |
| Synchronizer | cable to J8 and checked    |                          |
|              | 28V fuse. Found opened 28V |                          |
| 809080/000   | fuse.                      |                          |
+--------------+----------------------------+--------------------------+
| Azimuth      | When performing the        | Replace LRU, return      |
| Encoder      | Azimuth calibration on     | failed unit with fault   |
| Synchronizer | Channel A, noticed that    | description              |
|              | the data did not appear on |                          |
| 809080/000   | the AES display. All       |                          |
|              | lights on the display look |                          |
|              | normal except the data     |                          |
|              | lights.                    |                          |
+--------------+----------------------------+--------------------------+
| UPS          | Site Services icon on CMS  | Connect the Data cable   |
|              | appears red. Checked data  | to the proper port       |
| 808452/000   | cables to the UPS and      |                          |
|              | found it connected to the  |                          |
|              | "U-Talk" port instead of   |                          |
|              | the "Basic" port.          |                          |
+--------------+----------------------------+--------------------------+
| GPS Time     | GPS receiver shows a fault | Replace LRU, return      |
| Source       | light and the control      | failed unit with fault   |
|              | light goes out. No faults  | description              |
| 808281/005   | are sent to the LMT.       |                          |
+--------------+----------------------------+--------------------------+
| GPS Time     | GPS would not indicate or  | Replace LRU, return      |
| Source       | sync up with a received    | failed unit with fault   |
|              | signal.                    | description              |
| 808281/005   |                            |                          |
+--------------+----------------------------+--------------------------+
| GPS Time     | Unit appears dead          | Check power select       |
| Source       |                            | switch on back of LRU    |
|              |                            | and set to               |
| 808281/005   |                            |                          |
|              |                            | 115V operation instead   |
|              |                            | of 220V. Unit started up |
|              |                            | normal                   |
+--------------+----------------------------+--------------------------+
| GPS Time     | The GPS clock shows green  | Replace LRU, return      |
| Source       | lights but the GPS icon on | failed unit with fault   |
|              | the CMS is red.            | description              |
| 808281/005   |                            |                          |
|              | The following is reported  |                          |
|              | on the CMS log:            |                          |
|              |                            |                          |
|              | \[S\] 13:34:11 ATCBI6      |                          |
|              | :Bs:-12V Monitor Failed    |                          |
|              |                            |                          |
|              | \[S\] 13:34:11 ATCBI6      |                          |
|              | :Bs:Fault Cleared on Plot  |                          |
|              | Extractor Processor,RX/PE  |                          |
|              | Assembly,808365            |                          |
|              |                            |                          |
|              | \[S\] 13:34:11 ATCBI6      |                          |
|              | :Bs:Fault Cleared on GPS   |                          |
|              | Receiver                   |                          |
|              | TSU,External,808281        |                          |
|              |                            |                          |
|              | \[S\] 13:34:17 ATCBI6      |                          |
|              | :Bs:-12V Monitor           |                          |
|              | Serviceable                |                          |
|              |                            |                          |
|              | \[S\] 13:34:17 ATCBI6      |                          |
|              | :Bs:Fault On Plot          |                          |
|              | Extractor Processor,RX/PE  |                          |
|              | Assembly,808365            |                          |
|              |                            |                          |
|              | \[S\] 13:34:17 ATCBI6      |                          |
|              | :Bs:Fault On GPS Receiver  |                          |
|              | TSU,External,808281        |                          |
+--------------+----------------------------+--------------------------+
| System       | The LMT indicates CD2/SIU  | Replaced Ethernet cable. |
| Interface    | failure due to failed link |                          |
| Unit (SIU)   | in NUNIOs 1-3. Found bad   |                          |
|              | Ethernet cable to the SIU. |                          |
| SSG 752007   |                            |                          |
+--------------+----------------------------+--------------------------+
| System       | SIU is dead. The power     | Replaced power supply    |
| Interface    | lamp on the front of the   | module p/n               |
| Unit (SIU)   | power supply flickered and | VME100-3A-M155.          |
|              | then went out. Smoke was   |                          |
| SSG 752007   | observed.                  |                          |
+--------------+----------------------------+--------------------------+
| System       | NUNIO has no output from   | Replaced NUNIO module    |
| Interface    | channel 1. Channels 2, 3   | p/n 100-003707-G4.       |
| Unit (SIU)   | and 4 are normal.          |                          |
|              |                            |                          |
| SSG 752007   |                            |                          |
+--------------+----------------------------+--------------------------+
| System       | NUNIO has a constant fail  | Replaced NUNIO module    |
| Interface    | LED lit with all other     | p/n 100-003707-G4.       |
| Unit (SIU)   | LEDs lit as well after     |                          |
|              | power up. Reset did not    |                          |
| SSG 752007   | clear problem.             |                          |
+--------------+----------------------------+--------------------------+
| System       | Intermittent NUNIO         | Replaced SIU Hub p/n     |
| Interface    | failures.                  | 100-003707-G004.         |
| Unit (SIU)   |                            |                          |
|              |                            |                          |
| SSG 752007   |                            |                          |
+--------------+----------------------------+--------------------------+
| System       | CMS Log has a NUNIO Link   | Replaced NUNIO module    |
| Interface    | Failure.                   | p/n 100-003707-G4.       |
| Unit (SIU)   |                            |                          |
|              |                            |                          |
| SSG 752007   |                            |                          |
+--------------+----------------------------+--------------------------+
| AUI to RJ-45 | Intermittent NUNIO Link    | Switches not set         |
| Converter    | Failures.                  | correctly.               |
|              |                            |                          |
| 903000/028   |                            | There are two models     |
|              |                            | used with different      |
|              |                            | switch positions.        |
|              |                            |                          |
|              |                            | **Omnitron 4210:**       |
|              |                            |                          |
|              |                            | "SQE" switch to "SQE"    |
|              |                            | enable. "Duplex" switch  |
|              |                            | to "Half Duplex"         |
|              |                            |                          |
|              |                            | **KTI Networks KT-10T:** |
|              |                            |                          |
|              |                            | "SQE" Test set to ON and |
|              |                            | Link Test set to ON.     |
+--------------+----------------------------+--------------------------+
| Local        | LMT does not bootup.       | Check the power supply   |
| Maintenance  |                            | voltage select switch    |
| Terminal     |                            | and ensure that it is    |
| (LMT)        |                            | set for 115V operation   |
|              |                            | instead of 220V          |
| 807900/008   |                            | operation.               |
+--------------+----------------------------+--------------------------+
| Local        | No communications with the | The ribbon cable from    |
| Maintenance  | interrogators.             | the interface connectors |
| Terminal     |                            | on the back of the       |
| (LMT)        |                            | computer was loosely     |
|              |                            | connected to the comms   |
| 807900/008   |                            | card, secure this cable  |
|              |                            | connection.              |
+--------------+----------------------------+--------------------------+
| Local        | No communications with the | The comms card was loose |
| Maintenance  | interrogators.             | in its edge connector.   |
| Terminal     |                            | Reseated card.           |
| (LMT)        |                            |                          |
|              |                            |                          |
| 807900/008   |                            |                          |
+--------------+----------------------------+--------------------------+
| Local        | Serial Mouse inoperative.  | On the LMT configure the |
| Maintenance  |                            | MSINPUT.INI file for     |
| Terminal     |                            | SERIAL instead of PS2.   |
| (LMT)        |                            |                          |
|              |                            |                          |
| 807900/008   |                            |                          |
+--------------+----------------------------+--------------------------+
| Local        | When flashing the Comms    | This is due to the       |
| Maintenance  | card using the Batch       | device driver being      |
| Terminal     | command "CMSFLASH" the     | loaded. The device       |
| (LMT)        | expected checksum value    | driver must be REMed out |
|              | does not appear.           | in the AUTOEXEC.BAT and  |
| 807900/008   |                            | CONFIG.SYS files and     |
|              |                            | then the computer must   |
|              |                            | be rebooted.             |
+--------------+----------------------------+--------------------------+
| Local        | On bootup the LMT displays | Replace LRU, return      |
| Maintenance  | "hard disk error"          | failed unit with fault   |
| Terminal     |                            | description              |
| (LMT)        |                            |                          |
|              |                            |                          |
| 807900/008   |                            |                          |
+--------------+----------------------------+--------------------------+
| Local        | LMT CMS program returns    | Replace LRU, return      |
| Maintenance  | with error: No Device      | failed unit with fault   |
| Terminal     | Drivers opened! Also       | description              |
| (LMT)        | recorded text lines just   |                          |
|              | prior to error message     |                          |
| 807900/008   | window: ...reset release   |                          |
|              | FAILURE.                   |                          |
|              |                            |                          |
|              | \*\*\*\*NO COMMS SBC       |                          |
|              | DETECTED\*\*\*\*           |                          |
|              |                            |                          |
|              | Visual inspection did not  |                          |
|              | reveal anything            |                          |
|              | suspicious.                |                          |
+--------------+----------------------------+--------------------------+
| Site Monitor | WRTADS displays incorrect  | Checked Transponder and  |
|              | altitude for site monitor. | noticed it was not fully |
| 808412/001   |                            | seated into the mounting |
|              |                            | slot and was not making  |
|              |                            | contact with all of the  |
|              |                            | edge connector contacts. |
|              |                            | Re-seated Transponder    |
|              |                            | 808460/001.              |
+--------------+----------------------------+--------------------------+
| Site Monitor | WRTADS displays incorrect  | Reseated Control and     |
|              | altitude for the site      | Monitor PEC 808459/000.  |
| 808412/001   | monitor.                   |                          |
+--------------+----------------------------+--------------------------+
| Site Monitor | Site monitor would not     | Replace Site Monitor     |
|              | reply to interrogations.   |                          |
| 808412/001   | The altitude readout on    |                          |
|              | the front panel displayed  |                          |
|              | as follows: "\-\-\--"      |                          |
+--------------+----------------------------+--------------------------+
| Site Monitor | Site monitor failed to     | Replace Site Monitor     |
|              | reply to both MODE S and   |                          |
| 808412/001   | SSR at different times     |                          |
|              | over a 72 hr period.       |                          |
|              |                            |                          |
|              | CMS Log appeared as        |                          |
|              | follows:                   |                          |
|              |                            |                          |
|              | \[S\] 02:25:56             |                          |
|              | ATCBI6_1:Ar:Parrot 1       |                          |
|              | Missing                    |                          |
|              |                            |                          |
|              | \[S\] 02:25:56             |                          |
|              | ATCBI6_1:Bs:Parrot 1       |                          |
|              | Missing                    |                          |
|              |                            |                          |
|              | \[S\] 02:25:57             |                          |
|              | ATCBI6_1:Ar:Parrot 1       |                          |
|              | Failed                     |                          |
|              |                            |                          |
|              | \[S\] 02:25:57             |                          |
|              | ATCBI6_1:Bs:Parrot 1       |                          |
|              | Failed                     |                          |
|              |                            |                          |
|              | \[S\] 02:34:31             |                          |
|              | ATCBI6_1:Ar:Parrot 1       |                          |
|              | Present                    |                          |
|              |                            |                          |
|              | \[S\] 02:34:31             |                          |
|              | ATCBI6_1:Bs:Parrot 1       |                          |
|              | Present                    |                          |
|              |                            |                          |
|              | \[S\] 02:34:32             |                          |
|              | ATCBI6_1:Bs:Parrot 1       |                          |
|              | Serviceable                |                          |
|              |                            |                          |
|              | \[S\] 02:34:32             |                          |
|              | ATCBI6_1:Ar:Parrot 1       |                          |
|              | Serviceable                |                          |
+--------------+----------------------------+--------------------------+
| Site Monitor | The PARROT indicates       | The problem is corrected |
|              | failed and missing on the  | by programming the       |
| 808412/001   | LMT. The WRTADS display    | default code to the      |
|              | shows the PARROT operating | PARROTs assigned 3A      |
|              | but the code is 1200       | code.                    |
|              | instead of 1274. After     |                          |
|              | talking with a Bendix/King |                          |
|              | engineer, it was           |                          |
|              | discovered that there is   |                          |
|              | an intermittent problem    |                          |
|              | with some units that       |                          |
|              | causes it to switch to the |                          |
|              | default VFR code.          |                          |
+--------------+----------------------------+--------------------------+
| Modulation   | Reports wrong voltage to   | Replace LRU, return      |
| and          | LMT. The M&M card was      | failed unit with fault   |
| Monitoring   | causing the 65volt power   | description              |
| PEC          | supply to read a 55 volt   |                          |
|              | level and this is not      |                          |
| 80           | adjustable.                |                          |
| 8415/001/006 |                            |                          |
+--------------+----------------------------+--------------------------+
| Modulation   | Reports Zero output values | Replace LRU, return      |
| and          | on LMT TX monitor.         | failed unit with fault   |
| Monitoring   |                            | description              |
| PEC          |                            |                          |
|              |                            |                          |
| 80           |                            |                          |
| 8415/001/006 |                            |                          |
+--------------+----------------------------+--------------------------+