Restoring SINUMERIK 840D MMC103: HDD Ghost Image Troubleshooting

Problem Overview

The SINUMERIK 840D MMC103 (Man-Machine Communication) panel has historically been shipped with two distinct backup pathways: the legacy VALITEK cassette streamer used with early MMC100/MMC102/MMC103 units running Windows 3.11, and the GHOST disk-imaging workflow used from SW 3.x onward. When a service organization must restore a VALITEK-only archive onto a replacement HDD, the restoration typically fails with error patterns that are not seen on the newer PCU50 GHOST-based hardware. Field reports collected across multiple service organizations describe the same envelope of symptoms:

• The replacement HDD is recognized at BIOS POST, but the SINUMERIK runtime starts only after a long delay and the machine window fails to initialize.
• Regie/main window reports ERROR: Device unavailable shortly after SINUMERIK starts loading.
• Before SINUMERIK reaches its main window, the panel posts Corrupt Swap File Warning (Virtual memory).
• The Regie window logs WARNING Application 'param' didn't post InitComplete ! and the HMI stops responding.
• User screens cannot be opened; navigation back to the operator area returns a fault dialog, even when the user folders DH, N840D, NOVA are present at C:\840D-System.
• The same .gho image boots cleanly on a desktop PC running Windows XP, demonstrating that the archive itself is intact.

The combination of "clean on PC, broken on MMC" plus "all HDD candidates behave identically" rules out bad media and isolates the fault to the MMC103 hardware or its commissioning sequence. This article documents root causes, the step-by-step recovery procedure, and the verification checks compiled from the Siemens support database and practitioner field notes.

Affected Hardware and Software Stack

The MLFB suffixes -1AA0, -1AA1, -2AA1, -3AA1 denote progressive hardware revisions. Only revisions explicitly carrying VALITEK support can read VALITEK cassettes; later -DA21/-DB21 units in field stock sometimes arrive with GHOST-only firmware even when ordered as the VALITEK variant. Always confirm the suffix matches the suffix of the donor unit before commissioning.

Root Cause Analysis

Four independent root causes have been reproducibly identified when a VALITEK-era MMC103 fails to boot from a fresh HDD:

The official Siemens KB article "SINUMERIK 840D MMC103: A replacement hard disk is not recognized" identifies root cause #1 specifically and prescribes the BIOS remedy documented in this article. See the citation at the end of the recovery procedure.

Pre-Recovery Inspection

Before commissioning any spare HDD on a VALITEK-era MMC103, perform the following inspections. Skipping any of these will reintroduce the same fault mode after the next power cycle.

1. Confirm the MLFB of the donor MMC103. The -AA0/-AA1/-AA2/-AA2/-BA2 suffixes differ in firmware and supported backup medium. Cross-check the MLFB plate on the rear of the unit.
2. Verify the spare HDD matches the variant. A 6FC5247-0AA36-0AA1 spare HDD ordered from Siemens will match the variant declared at order entry. If a third-party 2.5" IDE HDD is used, capacity must remain within the original 2 GB / 10 GB / 20 GB / 30 GB window that the firmware expects; newer 80 GB+ drives are unsupported on MMC103 firmware.
3. Open the cabinet, confirm the IDE cable is 44-pin 2.5" type and the jumper on the HDD is set to Master. The MMC103 hosts no slave device.
4. Inspect the dampers. The MMC103 spare HDD ships with rubber dampers (P/N included with 6FC5247-0AA36-0AA1) that absorb spindle vibration; without them, repeated read errors surface as Device unavailable after 30-60 minutes.
5. Power the MMC103 once with the spare HDD attached and note the BIOS string. If the BIOS reports HDD type: USER or HDD type: MANUAL, the BIOS is in the failure mode described in the Siemens KB.

HDD Selection and Validation

Field experience shows that VALITEK-era MMC103 firmware accepts only a narrow range of IDE HDDs. Use the following accepted candidates:

Step-by-Step Recovery Procedure

1. Power down the MMC103 and disconnect the mains. Remove the four screws holding the front bezel and slide the HDD carrier out.
2. Connect the donor 2.5" IDE HDD to a workshop PC using a 44-pin IDE-USB adapter set to Master. Set the donor's jumper to Master; never use Cable Select on the MMC103 carrier.
3. Boot the workshop PC from Hiren's Boot CD (Windows XP PE) and verify the donor HDD appears as a fixed disk under Disk Management. Note the drive letter; do not use it as a bootable system drive.
4. Launch Norton Ghost 32 from the Hiren's menu. Choose Local > Disk > To Image and select the donor HDD. Save the image to a network share as mmc103_donor_YYYYMMDD.gho.
5. Attach the target (replacement) HDD to the workshop PC on the second channel of the IDE-USB bridge or via a second adapter. Initialize the disk using diskpart and create the same primary FAT16 partition plus one extended/logical partition layout as the donor, sized to the capacity of the target HDD.
6. In Ghost, choose Local > Disk > From Image and restore the donor image to the target HDD. Allow Ghost to resize the partitions if the target is larger; never shrink a 30 GB image onto a 2 GB disk.
7. Disconnect the target HDD from the workshop PC. Reinstall it into the MMC103 carrier with the dampers and mounting plate; verify the IDE connector is fully seated.
8. Power up the MMC103. Press DEL (or the BIOS hotkey shown on POST) to enter the BIOS setup utility.
9. Navigate to Standard CMOS Features > Primary IDE Master. Confirm the setting is AUTO. If the field reads USER or MANUAL, change it to AUTO, save (typically F10) and exit. The BIOS will redetect the target HDD geometry on the next POST.
10. Reboot. The SINUMERIK runtime should now mount the FAT16 partitions and proceed to the operator window.
11. Connect the MPI/PROFIBUS cable between the MMC103 and the NCU before applying mains to the NCU. Power the NCU; verify the NCK link is established on the HMI diagnostic page.
12. Reinstall the machine builder's user folders (DH, N840D, NOVA) using the builder's commissioning tool, not by manual copy. Restart the HMI service.

Recovery Flow

Specific Error Resolutions

2.1 BIOS Reports HDD type: MANUAL or USER

This is the documented Siemens failure mode. Even when the spare HDD is electrically healthy and recognized at POST, a BIOS stored in MANUAL mode means the firmware enumerates the disk using the geometry table from the original donor—geometry that no longer matches the spare. Result: the boot sector is read but the FAT16 partition table cannot be located, and SINUMERIK silently abandons startup. Per the Siemens KB article "SINUMERIK 840D MMC103: A replacement hard disk is not recognized", the remediation is to set the BIOS drive type to AUTO and rescan. See Siemens Support Entry 32985711 for the canonical description.

2.2 Corrupt Swap File Warning (Virtual memory)

This warning is posted when the SINUMERIK runtime attempts to enable the Windows 3.11 swap file at C:\WIN311\386SPART.PAR but the partition's free space is below the configured swap size. The warning is not a disk fault—it is a sizing fault. The Ghost image is restored with the swap file configured for the donor's geometry; when the partitions are resized for the spare, the swap-file size is preserved but the available space shrinks. Resolution:

1. Boot the MMC103 to the operator window despite the warning.
2. Open Regie > Setup > HMI > Memory.
3. Reduce Permanent Swap File to a value equal to or less than the smallest free partition.
4. Reboot. The warning will not appear if the swap file fits.

2.3 ERROR: Device unavailable

This is the generic failure when SINUMERIK cannot establish the NCK link. On a freshly restored MMC103 it almost always indicates that the MPI/PROFIBUS cable is not connected or that the NCU is unpowered. The runtime proceeds far enough to enumerate drives then blocks on the NCK handshake. Connect the MPI cable, apply mains to the NCU, restart the HMI service.

2.4 WARNING Application 'param' didn't post InitComplete !

The param application is the SINUMERIK parameter handler. It waits on the NCK to publish its configuration before it can finish its initialization handshake. If MPI/PROFIBUS is missing, param never receives InitComplete and the warning is logged. With the NCK link restored, the warning clears on the next HMI restart.

2.5 User Screen Fault Dialog

When the user folders are copied manually to C:\840D-System without registering them, the operator menu lists the screens but the registry keys in HKEY_LOCAL_MACHINE\SOFTWARE\SINUMERIK\UserData point to the old path. Two remediation paths exist:

• Restore the registry hive from the machine builder's commissioning backup.
• Reinstall the user folders using the builder's setup.exe with the original installation media; this regenerates the registry entries.

Do not use Windows Explorer to copy user folders; the SINUMERIK installer is the only supported deployment path.

MPI/PROFIBUS Re-Commissioning

The most common oversight on the bench is to power the MMC103 alone without the NCU. The Regie window will appear, but every NCK-dependent service will fail. Before fault-tracing user-screen failures, confirm the following:

1. PROFIBUS connectors at the MMC103 (X101) and the NCU (X126) are latched.
2. Terminating resistors at both ends of the PROFIBUS segment are in the ON position.
3. The MPI/PROFIBUS baud rate on the MMC103 (default 1.5 Mbit/s) matches the NCU configuration.
4. The NCU reports COMM OK on its seven-segment display prior to MMC boot.

Once the MPI/PROFIBUS link is established and the user folders are properly registered, user screens load on demand and the operator dialogue resumes without fault dialogs.

Software Stack Validation

If the HMI reports a system version older than the spare HDD's image, the loader will refuse to register; this is one of the documented causes of the param initialization warning when the spare HDD ships with a newer SW build than the rest of the controller stack.

Verification Procedure

1. Power up the NCU, then the MMC103. Verify POST completes and BIOS reports AUTO drive detection.
2. Confirm the SINUMERIK main window loads without Corrupt Swap File or Device unavailable errors within 90 seconds.
3. Open Regie and verify System Info displays the expected SW 3.6 / SW 3.7 build, not a partial string.
4. Navigate to the operator area; select each user screen and confirm the screen renders without fault dialog.
5. Trigger an axis jog from the HMI and observe the NCK response on the drive trace. If the axis responds within 200 ms, the MPI/PROFIBUS handshake is healthy.
6. Cycle mains and re-boot; the panel must reach the operator window within 90 seconds on cold start.

Spare HDD Sourcing Notes

Siemens currently supplies the MMC103 spare HDD under MLFB 6FC5247-0AA36-0AA1. When ordering:

• Quote the original MLFB of the donor MMC103 alongside the spare HDD order; Siemens will pre-configure the firmware loader to match.
• If the donor is -DA21-2AA1 or -DB21-3AA1, request a GHOST-formatted spare; the VALITEK tapes will not load on these variants.
• If the donor is -DA20-xAA1, request a VALITEK-formatted spare and the supporting cassette drive if it is no longer on-site.
• Always order two spare dampers; the rubber loses elasticity after 10+ years and must be replaced when the HDD is changed.

The Siemens KB entry "SINUMERIK 840D MMC103: A replacement hard disk is not recognized" (Siemens Support Entry 32985711) remains the canonical reference for the BIOS detection issue and is the source of the procedure documented in this article. For general HDD diagnostic methodology, see the Microsoft Learn reference Internal HDD troubleshooting on Microsoft Q&A.

Frequently Asked Questions