Siemens MJ-X Troubleshooting Manual

MJ-X

Troubleshooting Guide

Siemens Power Transmission & Distribution

Proprietary Information

[AED-000025-04]

Revision History

Document Revision 04: 5 January 98 -

Document number (AED-000025-04) added.

Document Revision 03: 14 July 97 -

This document was created from an original troubleshooting guide (dated May 93).

MJ-X Troubleshooting Guide AED-000025-04

1. Troubleshooting the MJ-X

This document outlines a process for preliminary troubleshooting of the MJ-X. The major objectives are:

1. determine if the fault resides at the MJ-X

2. check for improper jumper arrangements or other easily correctable conditions

3. check for field/customer repairable fault (e.g., bad fuse or Neutralite bulb)

4. If necessary, document problem details for factory repairs.

2. Basic Approach

For efficient troubleshooting, the following basic approach is recommended.

1. Verify configuration (hardware & software.)

2. Make sure the control panel hardware & software support the feature(s) you want to use.

3. (Consult MJ-X software revision documents.)

4. Substitute a known good panel. Check if it duplicates the symptoms. If so, the problem is more

likely with the system or wiring rather than with the MJ-X. (This is not always the case.)

5. Use this troubleshooting guide to isolate and fix the problem if possible. If field fix not feasible,

document problem in detail for factory repair.

The following assumes you are familiar with both the MJ-X operation and the MJ Suitcase Simulator. For
further information on these topics, refer to the appropriate user manuals. You also need to be familiar
with safety procedures for electrical and electronic equipment.

3. Test Equipment

Siemens recommends the following test equipment: 1) MJ suitcase simulator, 2) True RMS Volt/Amp
meter, and 3) PC running MJXplorer.

If using the MJ suitcase tester, connect to the PDS ("jack plug") cable. [As an alternative, provide a
nominal 120VAC at the external power banana plugs and a 0-200 mA current source at the PDS C2/E1.]
Unless otherwise noted, tests are performed with U2 and P2 at 120 VAC. [E must be connected to E1 at
the PDS if the suitcase tester is used for these tests.] {Caution: If using external power, be aware that
several of the PDS connections are hot.}

For tap motor direction sensing with the MJ-X, the “J” and “K” jack plug signals must have a minimal
resistive load. If you’re not using the MJ simulator, connect load resistors (2.2K 10W) from J to E and K
to E at the PDS (jack plug).

3.1. MJ Simulator Overview

The MJ suitcase simulator provides the following test capability: variable voltage sources (for U2 and P2),
variable current source (for C2), toggle switch for Straight/Inverted regulator simulation, toggle switch for
Inverted Source Side Potential Transformer (SSPT), Neutralite test button, Operations Counter test button,
Drag Hands Reset indicator, “J” (Raise) indicator, and “K” (Lower) indicator. With the MJ suitcase
simulator, you can simulate forward & reverse power flow, and leading/lagging power factor.

When pressed, the Neutralite and Operations Counter buttons ground (short to “E”) the jack plug signal
U12 and U10, respectively. Otherwise, these signals are open. The Drag Hands Reset Indicator lights
when the Drag Hands Reset signal (jack plug U11) has a nominal 120VAC. The “J” indicator lights
when the jack plug “J” signal has a nominal 120VAC. The “K” indicator lights when the jack plug “K”
signal has a nominal 120VAC.

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MJ-X Troubleshooting Guide AED-000025-04

MJ Simulator Voltage Source Connections:
Straight/Inverted
Switch

Inverted SSPT
Switch

“L” Voltage Source
Connection

“S” Voltage Source

Connection
Straight Doesn’t matter Jack plug “P2” Jack plug “U2”
Inverted INV SSPT Jack plug “U2” Jack plug “P2”
Inverted Off Jack plug “U2” none

Toggling the Power Flow Switch from Forward to Reverse changes the voltage-to-current phase
relationship from in-phase to 180° out-of-phase, respectively.

For tap motor direction sensing with the MJ-X, the MJ simulator must include load resistors (2.2K 10W)
from J to E and K to E. Check if your MJ simulator has these resistors. If your simulator lacks these
resistors, add them.

4. Jumper Tables

Make sure standard jumpers for both the power and main processor boards are in place for testing. See
tables below.

Power Board Jumper Table

Jumper

Designation

Jumper Connection Jumper

Type

Jumper

Location

Jumper Purpose

JP401 "+P" to "BAL" ("E" gnd) T.B. J405 1-2 For connecting balancing winding
JP402 "C" to "C2" T.B. J409 1-2 For connecting external current

meter

JP414 "U" to "U6" T.B. J405

10-11

JP415 "U6" to "U7" T.B. J405

12-13

For external control over tap motor
power signals
For external control of power for
MJ-X's (Auto) Tap Control Relays

JP416 "J21" to "J22" T.B. J405 4-5 For external control of (Auto) Raise

signal ("J") path

JP417 "K21" to "K22" T.B. J405 8-9 For external control of (Auto) Lower

signal ("K") path

(J402),

(J410)
(J408) (Version N power boards

External Source to Power
Switch

only) Auto Inhibit Input:
pulsed or latched

2 pin

header

3 pin

header

J402,

J410

J408:2-3

(pre-prod.

default)

For connecting an external source of
"External Power" to SW403
Auto Inhibit Input. For latched: use
J408:2-3. For pulsed: use J408:1-2.

(Version N power boards only)

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Main Processor Board Jumper Table

Jumper

Jumper

Location

J104 pins

part of 24

6&8

J110 3 pin

J111 3 pin

J113 3 pin

J115 3 pin

J116 2 pin

J117 2 pin

J118 2 pin

J119 2 pin

J120 2 pin

J121 3 pin

J122 3 pin

J123 2 pin

Type

pin

header

header

header

header

header

header

header

header

header

header

header

header

header

Jumper

Jumper Purpose

Position

IN (SW

Vers.2.03)

Out (SW

Vers.2.10 & up)

Connects DSACK0- to ground. (Indicates to uP that the data
bus is 8 bits rather than 16 bits.) This jumper needs to be
removed for connecting the test connector (J104) to the
Background Debug Mode (BDM) cable/interface.

2-3 1-2: For 128K x 8 Boot Flash device (28F001) at U2.

2-3: For 256K x 8 (any type) device (e.g., 28F020) at U2.

2-3 1-2: For 128K x 8 Boot Flash device (28F001) at U2.

2-3: For 256K x 8 (any type) device (e.g., 28F020) at U2.For

1-2 1-2: For 128K x 8 (or 32K x 8) Static RAM device at U3.

2-3: For 512K x 8 Static RAM device at U3.

1-2 1-2: Reset not asserted.

2-3: Reset asserted. (Connect this momentarily only.)

IN Connects D0 to pull down resistor. This connection is also

made with a trace on the circuit board for pre-production MP.

OUT Connects AGND to (digital) GND. Useful when testing MP

board by itself.

OUT Allows for a remote speaker to be used instead of the on

board speaker. (If remote used, remove on board speaker.)

OUT Connects (digital) GND to chassis, for protection.

IN For pre-production MP boards (version “0P”) only.

Connects data port connector shell to chassis, for protection.

1-2 1-2: For (local) data port wired as a "DCE".

2-3: For (local) data port wired as a "DTE".

1-2 1-2: For (local) data port wired as a "DCE".

2-3: For (local) data port wired as a "DTE".

IN For connecting DCE output handshake signals to local port

data connector (J106). (Out for DTE application.)

Unless otherwise noted, AC voltages are measured referenced to AC return ("E"). DC voltages are
measured reference to logic ground (GND). The logic ground is necessarily dc-isolated from the AC
return. Avoid connecting the logic ground to “E” or any other AC signals.

Note: The (local) data port should be jumpered as "DCE" for connecting to a terminal device (such as a
notebook or laptop computer) when using a straight-through cable. The (local) data port should be
jumpered as "DTE" for connecting to a modem when using a straight-through cable. Refer to MJ-X
Application Note 5 for further information.

5. Symptom Based Troubleshooting

Apply power and determine trouble symptom. Use Troubleshooting Symptom Tables below. [Find the
symptom that most completely describes what you are observing.]

Using MJXplorer, save the present MJ-X configuration and load “default” configuration.

To troubleshoot, use “known working” Power Board, Main Processor (MP) board, and MJ-X overlay. To
isolate faults, substitute the known good board/assembly. Make sure the "known good" board/assembly
has correct jumpering and configuration.

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MJ-X Troubleshooting Guide AED-000025-04

5.1. Troubleshooting Overview

Notes

1. Caution: Disconnect power source when removing cover. Observe ESD and safety precautions when performing checks.

2. To isolate a problem, substitute “known good” component (i.e., board assembly, device, or part) and check operation.

3. Refer to Instruction Manual for operating details.

4. For Any “Open Box” troubleshooting, always perform “Not Powering Up—Open Box” checks.

5. Check if 16-pin Terminal Block is seated and its jumpers are secure.

Symptom

Not Powering Up q Power Switch in correct position?

Displays Incorrect or
no Characters
Indicator(s) won’t light
(or won’t turn off)

Keypad fault q Some keys work?

No Source Voltage q “Type” configured correctly? Blown Sensing Fuse?

Calibration Off > 2%
(incorrect metering)
Cycles “Testing…” q Good power source (80-140 VAC)? See Notes 4&5. >> Isolate to Power or MP board. Calibrate if needed.
Tap won’t Raise/
Lower in Auto/Remote

Won’t Raise/Lower in
Manual
Drag Hands Reset
(DHR) Failure
Voltage Cal.
Terminals: No voltage
“Neutralite” off at
Neutral

Tap position incorrect
(See Notes 4&5.)

Operations Counter not
incrementing
(See Notes 4&5.)
Data Port not
communicating

Auto Inhibit Input
(T.B.) won’t work
Auto Inhibit Output
(T.B.) won’t work
Term. Block VRC
won’t work
Time/Date incorrect q Time/Date needs resetting? Battery low?

“Closed Box” {Perform these first}

q Blown Power and/or Sensing fuses?
q Blown External Source fuse?
q If used, PDS (jack plug) connected properly?
q Term. Block (16-pin) seated and jumpers secure?
q Good power source (80-140 VAC)?

>> See Note 4 & “Open Box”.
See Note 4 & “Open Box”. q Displays (DS1&DS2) seated properly in sockets?
q LEDs turn on in-sequence at power-up?

Noà probable overlay failure. Yesà Likely MP fault.
>> See Note 4 & “Open Box”.

Yesà probable overlay failure.
>> See Note 4 & “Open Box”.

>> See Notes 4&5.
q Configuration settings correct (U2, P2,C2 ratios)?
>> See Notes 4&5.

q Term. Block (16-pin) seated and jumpers secure?
q Auto Inhibit active? Low Current Inhibit active?

Set MJ-X R/A/M switch to Remote. With MJXplorer, perform
“Raise/Lower”. Verify J/K signal activates.
PDS J/K go active for Manual Raise/Lower attempt?
>> See Notes 4&5.
q When DHR switch on, U11 has nominal 120VAC?
>> See Notes 4&5.
For Inverted Reg.s w/o SSPT, there is no “P2”voltage”.
>> See Notes 4&5.
q Neutralite illuminates with Neutralite Test Switch?
Noà probable bad bulb. Yesà continue.
q Closing PDS-U12 to E illuminates indicator?
If no, probable power board fault. >> See Notes 4&5.
q Set MJ-X R/A/M switch to Remote. With MJXplorer,

perform “Raise/Lower”. Raise/Lower sensing OK?

q Configuration error?
q Closing PDS-U10 to E increments Operations Count?
Yesà configuration error? Noà See “Open Box”.

q Connect data port loopback (pins 2 & 3 shorted).
q Run “Backdoor Mode” Data Port Loopback test.

Failsà See “Open Box”. Passesà Check external cabling.
Verify internal MJ-X jumpers.
q “Backdoor” Auto Inhibit input Test good?
Configured correctly? See “Open Box”.

q Configuration error? q Connect “wetted” load to verify.
q “Backdoor” VRC input Test good?

q Configured correctly? Auto Inhibit inactive?
q “Backdoor Mode” Real Time Clock test good?

“Open Box”

q PROM oriented/seated correctly (no bent pins)?
q Connectors mated/seated/oriented properly?
q Socketed parts oriented/seated properly?
q Fuse connectors mated properly?
q Jumpers in correct positions?
q Components sheared off or missing?
q Charred/damaged parts or circuit board area?

>> Isolate to Power or MP board.

>> Isolate to Display Devices or “other” (MP board).

q Connector J102 mated/seated/oriented properly?
q Overlay cable damaged or cut?

>> Isolate to Front Panel Overlay or MP board.

q Connector J102 mated/seated/oriented properly?
q Overlay cable damaged or cut?

>> Isolate to Front Panel Overlay or MP board.
>> Isolate to Power or MP board.

>> Isolate to Power or MP board. Calibrate if needed.

>> Isolate to Power or MP board.
>> Verify Solid State Relay. (Substitute known good part.)

q Switches SW401& SW402 functional?
q Switch SW404 functional?
q U2/P2 Switch (SW405) functional?
q “Backdoor” Mode Neutralite Test good?

q “Backdoor” Mode Op Count Test good?
q “Backdoor” Mode Neutralite Test good?

q “Backdoor” Mode Op Count Test good?
q “Backdoor” Mode Neutralite Test good?

>> Isolate to Power or MP board.
q Verify data port jumpers (J121-123).
>> Isolate to MP board.

>> Isolate to Power or MP board.

>> Isolate to Power or MP board.
q “Backdoor” VRC input Test good?
>> Isolate to Power or MP board.
q “Backdoor” Mode Battery Test > 2.4V?

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5 version: 5 January 1998

MJ-X Troubleshooting Guide AED-000025-04

6. “Alert” Based Troubleshooting

Diagnose system and control panel problems using the Alert Messages and the table below. Rule out
“Normal Causes” first. Troubleshoot starting with “Problem Causes” and “What to Check”.

System transients may produce MJ-X Alert messages. If possible, determine if this is the case before
proceeding with an in-depth troubleshooting effort.

Alert
Name

Low
Current

Auto
Inhibit
Tap Track
Error

Neutral
Sig. Err
Tap Pos
????

Low PT
Thresh

Over
Current

NV RAM
Reset

Low
Battery

High
Voltage

Not In
Auto

R Limit
Reached
L Limit
Reached
Self Test
Fault
Pseudo
Manual

Normal Causes Problem Causes What to Check

Load current < low current
threshold (cfg.)

Auto Inhibit active via Term.
Block or communications
Incorrect tap tracking
configuration,
MJ-X needs to sense Neutral
Incorrect tap tracking
configuration
Incorrect tap tracking
configuration,
MJ-X needs to sense Neutral

Load Voltage < PT threshold
(cfg.)

Load current > over current
threshold (cfg.)

PROM update. Electrical transient causes loss of

Battery needs replacing. MJ-X circuit fault (on MP board.) Indicates that it is time to replace the Lithium Battery (on the MP

Load Voltage > high voltage
threshold (145 VAC)

Remote/Local-Auto/Local
Manual (R/A/M) switch not in
Auto
Tap position reaches MJ-X
Raise Limit (cfg.)
Tap position reaches MJ-X
Lower Limit (cfg.)

Remote communications control
in effect.

Bad C/C2 connections; MJ-X
circuit failure

Bad AutoInhibit input contacts;
MJ-X circuit failure
Bad regulator signals (U10,
U12); MJ-X circuit failure (J,K,
U10, U12 sense)
Bad regulator signal (U12); MJ­X circuit failure (U12 sense)
Bad regulator signals (U10,
U12); MJ-X circuit failure (J,K,
U10, U12 sense)

MJ-X circuit failure (U2/P2
voltage sense circuits)

Static RAM data. (Log &
min/max data lost.)

MJ-X circuit failure (U2/P2
voltage sense circuits)

MJ-X sensing for R/A/M Switch
inoperative; defective switch

See “Tap Pos ??” Alert See “Tap Pos ??” Alert

See “Tap Pos ??” Alert See “Tap Pos ??” Alert

PROM programmed incorrectly.
Bad RAM.

(Rule out “Normal” causes first!)

Caution: Keep current circuit “Closed” while connected to
regulator. Measure C/C2 current. Check C/C2 Terminal Block
jumper. Check E1 and C2 wiring. Calibrate the current.
Perform backdoor-mode test on Auto Inhibit input contacts.

Perform backdoor-mode test on these signals.

Check the Neutral (PDS-U12) and Operations Counter (PDS­U10) inputs using Backdoor-Mode test.
May indicate a temporary fault condition (failure to detect a
transition within the allowed time window on one of several input
lines.) Check the Neutral (PDS-U12) and Operations Counter
(PDS-U10) inputs using Backdoor-Mode test. If necessary,
substitute in the "known good" power board to isolate the problem
to the faulty (board) assembly.
This alert does not (necessarily) indicate an MJ-X fault condition.
Check to see if this alert condition goes away when both U2 and
P2 are above the (configurable) PT Threshold. If condition
persists, try substituting in the "known good" power board to
isolate the problem to the faulty (board) assembly.
This alert does not (normally) indicate an MJ-X fault condition.
Check to see if this alert condition goes away when an in-range
current (0-200 mA) is applied at C2/E1. If condition persists, try
substituting in the "known good" power board to isolate the
problem to the faulty (board) assembly.
May indicate a temporary fault condition. If condition appears
repeatedly, consult factory. Additional surge suppression may be
required for your installation.

board.) If condition persists after a good battery is installed,
check that the battery was installed properly. If fault persists,
substitute "known good" Main Processor board to isolate the
problem.
May indicate a temporary system fault condition. If condition
persists when in-range voltages (90-140 VAC) are applied to both
PDS-U2 and PDS-P2 inputs, perform calibration and input
voltage test. If condition persists, try substituting in the "known
good" power board to isolate the problem to the faulty (board)
assembly.
Substitute "known good" power board to isolate the problem to
the faulty (board) assembly. Check R/A/M switch operation.

Replace PROM. If problem persists, substitute "known good"
Main Processor board to isolate the problem.
Replace PROM. If problem persists, substitute "known good"
Main Processor board to isolate the problem.

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MJ-X Troubleshooting Guide AED-000025-04

7. Voltage and Current Calibration

Connect an external true RMS meter at the test point(s) for the signal. Apply the nominal calibration
voltage or current (per the table). Display the corresponding MJ-X calibration screen; (view these under
the <DIAGNOSTICS> menu.) Press the change key, then the up or down arrow to get the displayed
value to match the external meter value, then press the Save key.

Signal to
Calibrate

U2 PDS -- U2 Voltage Test

P2 PDS -- P2 Voltage Test

ILO PDS -- C2 to E1 C/C2 (J409- 1&2) 10 mA (AC RMS) ILO Cal
IMED PDS -- C2 to E1 C/C2 (J409- 1&2) 80 mA (AC RMS) IMED Cal
IHI PDS -- C2 to E1 C/C2 (J409- 1&2) 200 mA (AC RMS) IHI Cal

Test Signal
Application
Point

Test Signal
Measurement
Point

Terminals

Terminals

Nominal
Calibration Signal
Magnitude

120 VAC (RMS) U2 Cal SW405 = U2

120 VAC (RMS) P2 Cal SW405 = P2

MJ-X
Calibration
Screen

Conditions

8. MJ-X Self Tests

At start up, the MJ-X performs several self-tests, including: LED Indicator test, RAM read/write, and
PROM checksum.

The start-up LED Indicator test flashes all front panel LEDs three times. If one or more fail to flash, this
indicates a problem with the overlay, the overlay cable/connector, or the MJ-X Main Processor board.

The start-up RAM read/write test verifies the MJ-X non-volatile static RAM without effecting RAM­stored non-volatile data (e.g., log and min./max. data). RAM failures produce varying symptoms. For
complete failure, the MJ-X program will not run, and the MJ-X will appear “dead” with the exception of
display flickering when you power it. For loss of non-volatile data, the MJ-X clears all RAM-stored non­volatile data, and reports this in the Alert message “NV RAM Reset”. The MJ-X also displays the “NV
RAM Reset” alert message when the MJ-X detects a program memory (PROM) update or a checksum
error.

The MJ-X continuously runs PROM self-tests and reports the results in the <Diagnostics> menu
“Checksum” screen. MJ-X reports the checksum as “Pass” or “Fail”. A failed checksum indicates a
problem with the PROM.

9. MJ-X Internal Power Supply Signals

If you suspect an internal supply problem, verify the MJ-X power supply circuits per these specifications:

PDS-U2 VDC_U

(J403-7)
Vac min vdc max vdc min vdc max vdc min vdc max vdc Min vdc max vdc
90 14 20 4.75 5.25 8 15 8 15
145 32 40 4.75 5.25 18 25 18 25

Note: VISO1+ measured referenced to ISO1GND (J411-2). VISO2+ measured referenced to ISO2GND
(J411-4). VCC and VDC_U are measured referenced to (digital) ground (J403- 5&6).

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VDC_U
(J403-7)

VCC
(J403-13)

VCC
(J403-13)

7 version: 5 January 1998

VISO1+
(J411-1)

VISO1+
(J411-1)

VISO2+
(J411-3)

VISO2+
(J411-3)

MJ-X Troubleshooting Guide AED-000025-04

10. Backdoor Tests

Enter the “Backdoor Test” mode as follows:

1. For MJ-X Main Processor software versions prior to 2.30: Adjust input voltage or the MJ-X Voltage

and Bandwidth setpoints to achieve an in-band condition—i.e., deactivate J and K outputs.

2. Display the "Data Stat = XXXX" screen under the <COMMUNICATIONS> menu.

3. Set the Remote/Auto/Manual (“R/A/M”) Switch to Remote and the U2/P2 Switch to U2.

4. Press the following keys in the order listed: Left Arrow, Right Arrow, Left Arrow, Right Arrow, +/-.

While in the backdoor test mode, the Alert LED blinks continuously (at a slower rate than for the normal
product code.) Cycle the power or perform the watchdog test to exit the Backdoor Test mode.

10.1. “Backdoor” Tests

When entering the backdoor test mode, the MJ-X runs automatic checks and displays diagnostic messages
if appropriate. The MJ-X displays: "Test Code XXXXXX", where XXXXX is the backdoor test date code.

Keypad Test

Set the Remote/Auto/Manual (“R/A/M”) switch to Remote or Manual. Press any key. The MJ-X displays
the key’s name. Press the same key multiple times. The MJ-X alternately displays the key name and a
blank screen.

Remote/Auto/Manual Test

Toggle the Remote/Auto/Manual switch. The MJ-X displays the active switch position. For “AL” series
MJ-X units only: With the R/A/M switch in the Manual position, toggle the Tap Raise/Lower switch. The

MJ-X displays the Tap Raise/Lower switch position.

Indicator LEDs Test

Set Remote/Auto/Manual (“R/A/M”) switch to Manual. Set Tap Raise/Lower switch to Lower. The
Overlay LEDs (except Alert) turn on sequentially from top to bottom. The Alert LED blinks
independently at a regular rate. [This test may not always work. Use the Power-on LED test as a
substitute.]

Neutral Sense

Short the Neutralite signal (jack plug U12) to “E”. The MJ-X displays "Neutral Pos ON". Remove the
“E” ground connection. The MJ-X displays "Neutral Pos OFF".

Operations Counter Sense

Short the Operations Counter signal (jack plug U10) to “E”. The MJ-X displays: "Op Counter ON".
Remove the “E” ground connection. The MJ-X displays "Op Counter OFF".

VRC1(2) and Auto Inhibit Sense Test

Short the VRC1(2) terminals. The MJ-X displays "VRC En1(2) ON". Remove the short. The MJ-X
displays "VRC En1(2) OFF". Short the Auto Inhibit terminals. The MJ-X displays " Auto Inh ON".
Remove the short. The MJ-X displays " Auto Inh OFF".

Display Test

[Set the Remote/Auto/Manual switch to Auto. Press the Bandwidth key.] Turns on all segments, writes
test screens, changes brightness, then blanks the character display. This test continues until the
Bandwidth key is pressed again or some other key is pressed.

Speaker Test
[Set the Remote/Auto/Manual switch to Auto. Press the Voltage Level key.]

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MJ-X Troubleshooting Guide AED-000025-04

Turns on speaker driver with audio tone. (~ 2 seconds)

Battery Level Test
[Set the Remote/Auto/Manual switch to Auto. Press Time Delay.] Displays MJ-X battery voltage.

Local Port (SCI) Loopback Test

[Connect a loopback cable/connector (pins 2 & 3 shorted) to the MJ-X data port. Set the
Remote/Auto/Manual switch to Auto. Press the Alert key.] The MJ-X sends a canned message out the
data port and verifies that the same message is received back.

Reset Status Register

[Set the Remote/Auto/Manual switch to Auto. Press the Voltage Limit Control key.]
The MJ-X reads its MPU reset status register and displays the reset type, abbreviated as: "X" = external,
"P" = power up, "W" = watchdog, "H" = halt, "C" = loss of clock, "S" = system, and "T" = test module.
The reset types that will normally be observed include "X", "P", and "W". Other types may indicate a
problem with the MJ-X. [MJXplorer also reads/displays the Main Processor Reset Status Register.]

Watchdog Test

[Set the Remote/Auto/Manual switch to Auto. Press the Operations Counter key.]
The MJ-X discontinues updating the “watchdog timer”, forcing a reset. After resetting, the MJ-X resumes
normal product operations (i.e., the backdoor test mode is exited upon reset.)

Serial EEPROM (“SEEP”) Write/Read Test

[Set the Remote/Auto/Manual switch to Auto. Press the Cancel/Reset key.]
The MJ-X performs a non-destructive read/write test of the Serial EEPROM. Several memory locations
are written and then read back. The MJ-X reports Pass/Fail results.

Serial EEPROM (“SEEP”) Read Only Test

[Set the Remote/Auto/Manual switch to Auto. Press the Change or Save key. See below.] The MJ-X
reads/displays the values stored at a particular address within the SEEP.
If the Change key is pressed first (to initiate the SEEP read test), the SEEP read address starts at 20 (hex).
If the Save key is pressed first (to initiate the SEEP read test), the SEEP read address starts at 30 (hex).
Subsequently, pressing the Change key increments the SEEP address by 1. Pressing the Save key
increments the SEEP address by 16 (10 hex).

Serial EEPROM (“SEEP”) Erase

[Set the Remote/Auto/Manual switch to Auto. Press the Max/Min key. The MJ-X requests confirmation
before proceeding. Be sure you want to do this! Write down the settings for “MP BD VERS” and “PWR
BD VERS” before proceeding!]

The MJ-X re-initializes its configuration data to default values for whatever MP software version is
loaded into the program memory. After erasing, verify all configuration data. Restore the settings for
“MP BD VERS” and “PWR BD VERS”.

Real Time Clock (RTC) Tests

Note: For all RTC tests, set the Remote/Auto/Manual switch to Auto. Press key indicated in “[ ]”.

Read/Write: [Reactance] Reads/writes the RTC Control register. The MJ-X reports pass or fail.
Clear RTC Power Sense: [Menu] This performs no meaningful function.
Enable RTC Power Sense: [Up Arrow] This performs no meaningful function.
Status Register Read: [Down Arrow] The MJ-X displays the hex value for the RTC Status Register.
Interrupt Register Read: [Left Arrow] The MJ-X displays the hex value for the RTC Interrupt Register.
Control Register Read: [Right Arrow] The MJ-X displays the hex value for the RTC Control Register.

Siemens T&D

LLC

9 version: 5 January 1998

MJ-X Troubleshooting Guide AED-000025-04

11. “Backdoor Mode” Summary

1. For MJ-X Main Processor software versions prior to 2.30: Adjust input voltage or the MJ-X Voltage

and Bandwidth setpoints to achieve an in-band condition—i.e., deactivate J and K outputs.

2. Display the "Data Stat = XXXX" screen under the <COMMUNICATIONS> menu.

3. Set the Remote/Auto/Manual (“R/A/M”) Switch to Remote and the U2/P2 Switch to U2.

4. Press the following keys in the order listed: Left Arrow, Right Arrow, Left Arrow, Right Arrow, +/-.

Backdoor Test How to Start Conditions Expected Results

Auto Inhibit Sense Short or Open Term. Block

Battery Level Press Time Delay Key. R/A/M in Auto. Displays battery level. (Good battery reads > 2.4V)
Data Port (Loop Back test) Press Alert Key. R/A/M in Auto. Pins 2&3

Display Press Bandwidth Key. R/A/M in Auto. Turns on all segments, writes test screens, changes

Indicator LEDs Raise/Lower switch in

Keypad Press any key. R/A/M in Manual. MJ-X displays key name. Alternately blanks for

Neutral Sense Close/Open jack plug “U12”

Operations Counter Sense Close/Open jack plug “U10”

Remote/Auto/Manual
Switch
Real Time Clock (RTC)
Read/Write
Reset Status Register
[MJXplorer also
reads/displays the MJ-X
Main Processor Reset Status
Register.]
Serial EEPROM Erase

Caution! Causes loss of
stored configuration data.

Serial EEPROM Read Only Press Change or Save to start.

Serial EEPROM
Read/Write
Speaker Press the Voltage Level key. R/A/M in Auto. Turns on speaker driver with audio tone. (~ 2 seconds)
Tap Raise/Lower Toggle Raise/Lower Switch. R/A/M in Manual. For AL series units ONLY, the MJ-X displays Tap

VRC1, VRC2 Short or Open Term. Block

Watchdog Press the Operations Counter

Unused tests: (all with R/A/M in Auto)
Clear RTC Power Sense—Menu key, Enable RTC Power Sense—Up Arrow key, RTC Status Register Read—Down Arrow key, RTC
Interrupt Register Read—Left Arrow key, RTC Control Register Read—Right Arrow key.

contacts.

Lower.

to “E”.

to “E”.
Toggle R/A/M switch. MJ-X displays the switch position.

Press the Reactance Key. R/A/M in Auto. Displays pass/fail results of RTC test

Press the Voltage Limit
Control key.

Press the Max/Min key.
{MJ-X request confirmation}

Subsequent Change key
presses increment the address
by 1. Pressing the Save key
increments the (hex) address
by 16.
Press the Cancel/Reset key. R/A/M in Auto. Displays pass/fail results of non-destructive Serial

contacts.

key.

“Remote Auto Inhibit”
Indicator turns on when
contacts closed

shorted for looping back.

R/A/M in Manual.
Tap Raise/Lower in Lower.

R/A/M in Auto. Displays last reset type: "X", "P", and "W" are normal.

R/A/M in Auto. Write down
“MP BD VERS” and “PWR
BD VERS” before
proceeding!]

R/A/M in Auto.
Pressing Change first initiates
the read address to 20 (hex).
Pressing Save first initiates the
read address starts to 30 (hex).

R/A/M in Auto. MJ-X forces watchdog reset, exits Backdoor mode.

Display toggles from “AutoInh On” to “AutoInh Off”

Displays pass/fail results for data port test (is
transmitted message received back?)

brightness, then blanks the character display. Repeats.
The Overlay LEDs (except Alert) turn on sequentially
from top to bottom.
{The Alert LED blinks independently at a regular
rate.}

multiple keypresses.
Display toggles from “Neutral Pos ON” to “Neutral
Pos OFF”
Display toggles from “Op Counter ON” to “Op
Counter OFF”

Others may indicate an MJ-X problem. [X=external,
P=power up, W=watchdog, H=halt, C=loss of clock,
S=system, and T=test module.]

Re-initializes configuration data to defaults for

whatever MP software version is loaded into the
program memory. After erasing, verify configuration

data. Restore settings for “MP BD VERS” and “PWR
BD VERS”.
Displays Serial EEPROM binary data.

EEPROM read/write test.

Raise/Lower switch position.
Display toggles from “VRC EnN ON” to VRC EnN
OFF” (where N = 1 or 2)

************** These need to be included in the next update: ***********************
Fault Isolation for:

q Expansion Rack
q Communications Module

Siemens T&D

LLC

10 version: 5 January 1998