Resolving Mori Seiki TV-30 Memory Mode Cycle Start

Press Cycle Start in Auto (memory) mode and the green lamp stays dark, yet the same code runs in MDI. Start with the active CNC error state: the ladder drops Cycle Start OK1 (M845) when ER&ALM (M1833) is true, while the MDI path can restore the permissive through MDISOK (M1050). On this TV-30, renewing the four-cell encoder backup battery module cleared the remaining battery warnings and restored Auto operation.

Read the panel pattern first

The operating-mode split is the strongest diagnostic clue. A bad program, damaged Cycle Start pushbutton, or failed lamp would not normally explain why code executes in MDI but never starts in Auto.

Panel symptom	Diagnostic meaning	First check
Z70 ABS. ILLEGAL XYZ appears after battery voltage drops	The absolute position reference has been lost or invalidated.	Perform the correct zero-point initialization procedure, then confirm that Z70 clears.
Z70 clears, but Auto Cycle Start remains disabled	Zero initialization corrected the position-reference fault, but another CNC error state still blocks the Auto permissive.	Check the remaining messages and ladder state of M1833 and M845.
Z73 ABS. WARNING 0001 XYZ and S52 SERVO WARNING 009F Z remain active	The encoder backup battery condition has not been corrected. A message labeled as a warning can still participate in machine-side interlocking.	Inspect and service the encoder battery module rather than repeating zero initialization.
MDI runs, but memory mode does not	The MDI exception path is active while the normal Auto permissive is false.	Monitor M1050, M1833, and M845 while changing modes.
The green Cycle Start lamp never illuminates in Auto	The start command is not reaching an accepted Cycle Start state.	Diagnose the permissive chain before replacing the switch or lamp.

Trace the Cycle Start interlock

The relevant ladder relationship is direct: M845 is false when M1833 is true, unless M1050 is true. Read the three bits as a decision chain:

• M1833, labeled ER&ALM, represents the CNC error/alarm condition used by this rung.
• M845, labeled Cycle Start OK1, is the permissive required for normal Cycle Start.
• M1050, labeled MDISOK, provides the MDI-specific path that allows execution despite the state blocking Auto.

This is why the mode selector changes the symptom. In Auto, an active M1833 holds M845 false. In MDI, M1050 can make M845 true. The CNC can therefore execute a manually entered block even though memory-mode Cycle Start remains inhibited.

Do not decide that a message is harmless solely because the display calls it a warning. The display classification and the machine builder's ladder permissives serve different purposes. Monitor the bits during the fault: if M1833 is true and M845 changes only when MDI asserts M1050, the ladder has identified the immediate reason for the mode-dependent behavior.

Separate the three battery locations

The control contains three battery-backed areas using the same 3.6 V AA-size leaded cell, but they protect different data. Replacing a cell in the wrong area wastes time and leaves the active warning untouched.

• The encoder backup module uses four cells. Loss of this backup caused the absolute-position alarms, and renewal of these cells restored Auto operation in the affected machine.
• A cell on the control board in the rear electrical cabinet retains CNC parameters, programs, and other CNC data.
• A cell in the operator-panel cabinet retains Dialog programming data, Dialog parameters, and GOP touchscreen parameters.

Do not calculate or assume the encoder module voltage by multiplying the cell ratings. The evidence identifies four 3.6 V cells but does not define their electrical arrangement. Match the original module construction, polarity, lead arrangement, and specified cell type exactly.

The control-board and operator-panel batteries do not necessarily produce a written alarm when low. A small on-screen battery symbol can be the only indication. Treat that symbol as a service condition before stored parameters or programs disappear.

Preserve every battery-backed data set

Back up the machine before opening a battery circuit. A battery repair can solve the Cycle Start problem while creating a much larger recovery job if a different backed-up area loses power.

1. Export CNC parameters, programs, and other transferable CNC data through the available RS232 or memory-card function.
2. Validate the backup by confirming that the expected files exist and are readable. A backup command completing without a useful file is not a recovery plan.
3. Write down or photograph every GOP parameter screen.
4. If Dialog Programming is used, record its programs and parameters separately.
5. Test the Dialog memory-card save function before depending on it. One installation returned a card error when the card already contained other data, so keep a manual record even when the menu offers a save function.
6. Record the active alarms, current absolute-position state, and any battery symbols before service.

The reported capacitor-backed retention window with power removed is approximately 30 minutes. Treat that as a design expectation, not a usable maintenance timer. Aging capacitors lose storage capacity, so an older control may retain data for much less time.

Restore the battery condition in a controlled sequence

Start here after confirming the ladder pattern. The successful repair renewed the four 3.6 V AA-size leaded cells on the encoder battery board; it did not require another program edit.

1. Capture all backups and manual parameter records before disconnecting any battery.
2. Identify the encoder backup module positively. Do not confuse it with the rear control-board battery or operator-panel battery.
3. Read the removed module's polarity, cell orientation, lead arrangement, and connection points. Photograph them before disturbing the assembly.
4. Obtain the correct replacement module or have the existing board rebuilt by personnel qualified to solder battery assemblies. Use four matching 3.6 V AA-size leaded cells where a board rebuild is the selected repair.
5. Follow the machine manufacturer's battery-replacement and power-state procedure. The completed repair on this machine was performed with mains power maintained, but an energized electrical cabinet presents hazardous voltage and is not a general field instruction.
6. If the approved method requires energized work, assign it to qualified electrical service personnel using the site's electrical safe-work controls. If those conditions are unavailable, stop and use authorized service.
7. Replace connections one for one without reversing polarity, shorting a cell, or interrupting another battery-backed circuit.
8. After service, check the alarm display and battery symbols. If the absolute reference was lost again, repeat only the documented zero-point initialization needed for the affected axes.
9. Select Auto mode and recheck the Cycle Start permissive before attempting a production cut.

Verify the repair at the ladder and machine

A cleared screen is only the first test. Prove that the cause, interlock, and operating function have all returned to normal.

1. Confirm that Z73 ABS. WARNING 0001 XYZ and S52 SERVO WARNING 009F Z no longer remain active after the battery repair and required reset sequence.
2. Confirm that Z70 ABS. ILLEGAL XYZ remains cleared and that machine zero is valid.
3. Monitor M1833 in Auto. The error/alarm condition that blocked the rung must no longer hold the start permissive false.
4. Confirm that M845 becomes true through the normal Auto path without relying on M1050.
5. Press Cycle Start in Auto and verify that the green lamp now illuminates.
6. Use the machine's approved prove-out method to run a known program without an initial cutting load. Verify commanded motion, reference position, and program progression before returning the machine to production.
7. Switch back to MDI and confirm normal MDI execution. Both operating modes should now work without using MDI as a workaround.

If the battery warnings clear but M1833 stays true, read the remaining CNC messages and trace the other conditions feeding that bit. Do not bypass M845; doing so removes a machine-builder interlock without correcting its input.

Avoid the fixes that waste time

• Do not repeat zero-point initialization after Z70 has cleared unless the absolute reference is lost again. Initialization repairs reference data; it does not renew the battery that caused the loss.
• Do not troubleshoot the part program first when the same code executes in MDI and the Auto Cycle Start lamp never turns on. The permissive is failing before normal execution begins.
• Do not replace only the rear control-board or operator-panel battery when the active messages identify the encoder backup problem. Service each battery-backed domain according to its own warning and maintenance state.
• Do not trust the approximate 30-minute retention period on an aging control. Finish and validate backups before starting.
• Do not depend solely on the Dialog memory-card menu. Record Dialog and GOP parameters manually as a second recovery path.
• Do not clear, force, or jumper ladder bits to make M845 true. Use the ladder as a diagnostic display, then correct the condition driving M1833.
• Do not treat energized battery replacement as a routine shortcut. Maintaining backup power may preserve data, but cabinet access under power requires an approved procedure and qualified personnel.

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