Atari Megafile Troubleshooting Guide
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Fault-finding for the Atari Megafile hard disk drives, the Atari Megafile 30 and Atari Megafile 60. It draws on the troubleshooting and error-message appendices of Atari's owner's manual, on owners' repair reports, and on Atari's controller drawing C103166.[1][2] The drive contains a mains power supply; unplug it before opening the case. Care and opening are covered in Atari Megafile General Maintenance.
Before anything else
[edit | edit source]Atari's manual names a loose cable or a drive that has not been switched on as the most common fault, and tells owners to check those first.[1]
- The interface cable runs from the computer's Hard Disk port to the Megafile's Hard Disk In socket, and from Hard Disk Out to the next device. Secure both ends.[3]
- Switch the Megafile on first and wait until its busy light goes out and the drive stops whirring before switching on the computer.[3]
- When booting from floppy, the boot disk needs AHDI.PRG in its AUTO folder, or the desktop shows no hard disk icon.[1]
- With more than one drive on the chain, each needs its own unit number. All Megafiles leave the factory as unit 0, and an SH204 has to be the last device.[3]
Things that are not faults
[edit | edit source]- The drive takes about 22 seconds from power-up to ready, and 20 seconds to stop.[4]
- The busy light blinks briefly at power-up.[3]
- The drive is loud. An owner describes the head movement at power-up as sounding "a little like a steam train", audible over the fan.[5]
- A few bad sectors. Atari says it is normal for defective spots to develop with use, and Markbad locks them out.[6]
Atari's troubleshooting chart
[edit | edit source]| Problem | Atari's suggested solution |
|---|---|
| Power light does not come on | Check that the power cable is secure at both ends and that the outlet works. |
| Drive does not whir and the busy light does not come on | Check all hard disk cables and that the drive is switched on. When booting from floppy, use a working disk in drive A. If the fault stays, take the drive for servicing. |
| Hard disk icon C does not appear | Check the connection and that the drive is on. A boot floppy must have AHDI.PRG in its AUTO folder. When booting from the hard disk, back up and reformat. |
| System will not boot from the hard disk | Run HINSTALL. If that fails, back up and reformat. |
| A program will not start from the hard disk | The program may be damaged or not written to start from a hard disk. Try another copy from floppy, then the program's publisher. |
For unreadable data, Atari gives this recovery sequence:[1]
- Run the HDX Markbad option on each logical drive with unreadable data, and recover what you can.
- Back up the recovered data to floppy.
- Erase the problem logical drive with the HDX Zero option and run Markbad on it again.
- Copy the backed-up data back.
If the boot partition (drive C on unit 0) is damaged, boot from the utilities disk, follow the same steps, and reinstall the driver with HINSTALL.[1]
Error messages
[edit | edit source]| Message | Program | Atari's solution |
|---|---|---|
| Cannot format <unit>! Try checking all the connections and reformatting it. | HDX Format | Make sure the drive is securely connected, then reformat. |
| Cannot find format parameters for disk type <name> | HDX | Make sure the original WINCAP file is on the disk with HDX. |
| Cannot find partition scheme <name> | HDX Partition | Use the original WINCAP file. Do not modify WINCAP: doing so may destroy the disk. |
| Bad Sector List is corrupted! | HDX | Back up the disk and reformat it. |
| Cannot read Root Sector from the disk! | HDX, HINSTALL | Back up the disk and reformat it. |
| Cannot create driver file at destination! | HINSTALL | The root directory may be full: delete files to make room. If it is corrupted, back up what you can and reformat. |
| Cannot open driver source file! | HINSTALL | Make sure SHDRIVER.RAW is on the disk with HINSTALL.PRG. |
Formatting asks for a label number
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Atari's 1989 errata sheet warns that after the drive type is chosen in step 4 of the formatting procedure, HDX may show a further box, "Select the unit type", with a list of label numbers and a NO LABEL button. Read the number on the Megafile label on the rear of the drive and pick the matching box.[8] The Megafile 60 at the University of Waterloo Computer Museum carries a sticker reading "SEA 5 065" on its rear panel, which matches the SEA5065 entry in Atari's example.[9][8]
Faults reported by owners
[edit | edit source]Drive spins up, then clicks, and is "not responding"
[edit | edit source]In 2005 an owner's Megafile 30 spun up and then clicked continuously, and the Atari utilities reported it as not responding. Forum members took the clicking as the heads failing to read the disk and the drive as finished. The owner opened the sealed drive and found the clicking came from the head stepper; it still was not recognised.[10] Opening the sealed head and disk assembly lets dust onto the platters, as other members pointed out in the same thread.[10] A drive in this state needs a replacement mechanism or an emulator; see Atari Megafile General Maintenance#Replacing the drive mechanism.
Lights and fan on, but "unit 0 - no identification"
[edit | edit source]In 2017 a Megafile 60 powered up with its lights and fan working; the red activity light went out after 40 to 50 seconds. AHDI reported "unit 0 - no identification", and HDX could not format any unit. The fault was the same on two different computers.[5] Suggestions in the thread were to check that the cable is in the correct socket, to listen for the heads seeking at power-up, and to suspect the power supply capacitors or the controller board; one member's Megafile 20 had a dead board.[5] The thread ends without a diagnosis. Work through the checks under #Controller board checks before condemning the mechanism.
Slow to start or stuck
[edit | edit source]Owners report a Megafile that came to life after being left switched on for an hour, one that takes a while to warm up, and mechanisms that stick.[11][5] If nothing can be heard from the drive at power-up, one owner suggests that it has stuck or seized.[5]
Works when cold, fails when warm
[edit | edit source]One owner's Megafile 30 worked for about 30 minutes and then became too hot to read anything.[12] Check that the fan turns and that the vents are clear; the fan runs from +12 V on J8 of the controller board.[2] Atari's operating range is 10 to 50 °C.[4]
Bad sectors and lost data
[edit | edit source]An owner reports that the Seagate ST-238R drives lose data over time and work again for a while after a low-level format; another's Megafile came back with two bad sectors after formatting, and a third saved a "dead" Megafile by low-level formatting it.[12][11] HDX's Format option formats the whole unit, runs Markbad over it and partitions it again, erasing everything.[13] Back up first if the drive can still be read.
Controller board checks
[edit | edit source]Drawing C103166 Rev. 4 is the reference for these. Some Megafile 30s have a different board marked "SH205 C100169", so read the number on your board first.[2][14]
| Check | Where | What the drawing shows |
|---|---|---|
| Supply rails | J5 | +5 V on pins 1 and 2, +12 V on pin 6, ground on pins 3 to 5 |
| Drive power | J9 | Both rails passed on to the mechanism |
| Fan power | J8 | +12 V |
| Processor reset | U7 (8085) pin 36 | Reset network C5 (10 µF), R5 (27 kΩ), CR1 (1N4148) |
| Processor clock | Y1 | 6 MHz crystal on U7 |
| Data separator clock | Y2 | 15 MHz crystal on U12 (32D5321) |
| Unit number | SW1, U18 (74LS85) | Three-position switch read by the comparator |
Atari gives no test voltages beyond the nominal rails. The electrolytic capacitors on the board are listed in Atari Megafile General Maintenance#Capacitors.
Related pages
[edit | edit source]- Atari Megafile 30
- Atari Megafile 60
- Atari Megafile General Maintenance
- Atari Megafile Documentation
- Hard Drive Maintenance and Repair
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Atari Corporation, MEGAFILE Hard Disk Drive Owner's Manual, C300459-001 Rev. B, 1988, appendix A, "Troubleshooting", pp. 43-45 (PDF pp. 45-47).
- ↑ 2.0 2.1 2.2 2.3 Atari Corporation, Schematic Diagram, Megafile 60 (RLL), drawing C103166 Rev. 4, drawn 23 March 1988, in Schaltungsdienst Lange, Megafile 30, Megafile 60 Service Manual, PDF pp. 2-3. Hosted as File:Atari Megafile 30 and 60 Service Manual (Schaltungsdienst Lange).pdf.
- ↑ 3.0 3.1 3.2 3.3 Atari Corporation, MEGAFILE Hard Disk Drive Owner's Manual, C300459-001 Rev. B, 1988, chapter 1, pp. 3-7 (PDF pp. 7-11): connecting one or more drives, unit numbers, switching on and off. Hosted as File:Atari Megafile Owner's Manual C300459-001 Rev B.pdf.
- ↑ 4.0 4.1 Atari Corporation, MEGAFILE Hard Disk Drive Owner's Manual, C300459-001 Rev. B, 1988, appendix C, pp. 53-54: start and stop times, operating temperature.
- ↑ 5.0 5.1 5.2 5.3 5.4 AtariAge Forums, "Install Megafile 60", January 2017. Forum thread.
- ↑ Atari Corporation, MEGAFILE Hard Disk Drive Owner's Manual, C300459-001 Rev. B, 1988, p. 34 (PDF p. 36): marking bad sectors.
- ↑ Atari Corporation, MEGAFILE Hard Disk Drive Owner's Manual, C300459-001 Rev. B, 1988, appendix B, "Error Messages", pp. 47-51 (PDF pp. 48-52).
- ↑ 8.0 8.1 Atari Corporation, errata sheet for the MEGAFILE owner's manual, C300707-001 Rev. A, 1989. Hosted as File:Atari Megafile Owner's Manual Errata C300707-001 Rev A.pdf.
- ↑ University of Waterloo Computer Museum, "Atari MEGAFILE 60 [2017.11.63"], rear-panel photograph (retrieved 6 October 2026).
- ↑ 10.0 10.1 atari-forum.com, "megafile 30 problem - clicking noises!", October-November 2005. Forum thread.
- ↑ 11.0 11.1 AtariAge Forums, "Two dead Megafile 30s, options for MF drives", April 2024: drives revived by low-level formatting or by running for an hour; drives that stick. Forum thread.
- ↑ 12.0 12.1 atari-forum.com, "Atari MegaFile Hard Drive Replacement", posts by tzok, jd and rcamp48, January-February 2023. Forum thread.
- ↑ Atari Corporation, MEGAFILE Hard Disk Drive Owner's Manual, C300459-001 Rev. B, 1988, pp. 14-17 (PDF pp. 17-20): formatting.
- ↑ AtariAge Forums, "Megafile capacitor replacement", August 2022: a Megafile 30 with an SH205 C100169 Rev. 5 board. Forum thread.