Atari SH204 Troubleshooting Guide
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Fault-finding for the Atari SH204 hard disk drive, from Atari's SH Hard Disk Drive Owner's Manual (C026263 Rev. B, 1986), its controller error codes, and owners' reports.[1][2] For the drive mechanism, see also Hard Drive Maintenance and Repair.
The drive contains a mains power supply. Unplug it before opening the cover (Atari SH204 General Maintenance#Opening the case).[3]
Before anything else
[edit | edit source]| Symptom | Check |
|---|---|
| Drive does not respond, will not come on, or no hard disk icon | Switch everything off. Check that every cable is correct and secure. |
| Fan and busy light do not come on at power-up | Tighten the fuse holder on the back panel; if necessary replace the fuse (1½ A type 3AG in the United States; the European unit's label gives T1.6A 250 V).[5] |
| Drive switches itself off in use | The same fuse checks. If a new fuse fails, the unit needs repair. |
| Hard disk icon missing after booting from floppy | Allow the drive at least 15 seconds to initialise before switching on the computer. Boot with a disk that has AHDI.PRG in its AUTO folder, the computer switched on last. |
| System will not start consistently | The working boot disk may be corrupt. Boot from the original SH Boot Disk and, if that works, make a new working copy. |
| One program fails with the hard disk | The program may not support a hard disk; ask its publisher. |
Things that are not faults
[edit | edit source]- The drive whirs, seeks and beeps for about 15 seconds at power-up before the busy light goes out.[4]
- The ST needs TOS in ROM to use the drive. A machine with disk-loaded TOS cannot.[6]
- GEM limits: no more than 40 directories and folders across all mounted drives, 400 items shown in open windows, 256 items in a drive's main directory, and 14 hard disk icons on the desktop. One partition cannot be copied to another with the desktop's disk copy.[6]
- With more than one drive, each needs its own unit number (see Atari SH204 General Maintenance#Unit number switches), and an SH204 must be the last drive on the DMA chain.[3][7]
Controller error codes
[edit | edit source]The SH204's controller returns a four-byte sense block to the REQUEST SENSE command (operation code 0x03), with the error code in the low seven bits of the first byte.[8][2]
| Group | Code | Meaning |
|---|---|---|
| Drive | 0x00 | No error |
| 0x01 | No index | |
| 0x02 | No seek complete | |
| 0x03 | Write fault | |
| 0x04 | Drive not ready | |
| 0x06 | No track zero | |
| Controller | 0x10 | ID ECC error |
| 0x11 | Uncorrectable data error | |
| 0x12 | ID address mark not found | |
| 0x13 | Data address mark not found | |
| 0x14 | Record not found | |
| 0x15 | Seek error | |
| 0x18 | Data check in no-ECC mode | |
| 0x19 | Data ECC error | |
| 0x1C | Bad format | |
| 0x1D | Self test failed | |
| Command | 0x20 | Invalid operation code |
| 0x21 | Invalid block address | |
| 0x23 | Invalid final address | |
| 0x24 | Invalid argument | |
| 0x25 | Invalid device number |
The manual groups the codes into drive, controller and command errors. For read errors on the disk surface, HDX can mark bad sectors in a logical drive, and a reformat with HDX rewrites the whole unit; both destroy data, so back up first.[2][9]
The controller command set is small: Test Drive Ready (0x00), Request Sense (0x03), Format Drive (0x04), Read (0x08), Write (0x0A), Seek (0x0B) and Mode Select (0x15). Test Drive Ready returns zero status if the drive is powered and ready.[8]
Inside the drive
[edit | edit source]The SH204 has three separate parts behind the DMA port: the host adapter card at the back (Atari schematic C026198), the disk controller board with its Adaptec chips, and the 5.25-inch drive, plus the power supply and fan.[10][11][12] Atari's manual describes the controller as the host adapter plus an intelligent SCSI controller for ST506/412 drives.[8] The host adapter's three-way DIP switch sets the unit number, so a drive that spins up but is not found at the expected unit is worth checking there first.[3][10]
Faults reported by owners
[edit | edit source]- ANALOG Computing described the later Megafile 20 in 1989 as a major improvement over the SH204, "with fewer bugs in its controller".[13]
- An owner who bought an SH204 without its drive in 2019 was told on the exxos forum that it needs an ST506-type (MFM or RLL) mechanism, and that bypassing the converter board might allow a SCSI disk.[14]
Related pages
[edit | edit source]- Atari SH204
- Atari SH204 General Maintenance
- Atari SH204 Documentation
- Atari Megafile Troubleshooting Guide
- Hard Drive Maintenance and Repair
References
[edit | edit source]- ↑ 1.0 1.1 SH Hard Disk Drive Owner's Manual, appendix A, Troubleshooting, p. 23 (PDF p. 29).
- ↑ 2.0 2.1 2.2 2.3 SH Hard Disk Drive Owner's Manual, appendix B, Status Error Codes, pp. 31-32 (PDF pp. 37-38).
- ↑ 3.0 3.1 3.2 SH Hard Disk Drive Owner's Manual, chapter 3, Setting the DIP Switches, pp. 19-21 (PDF pp. 25-27).
- ↑ 4.0 4.1 Atari Corp., SH Hard Disk Drive Owner's Manual, C026263 Rev. B, 1986, chapter 1, Booting the Hard Disk Drive, pp. 6-7 (PDF pp. 12-13). File:Atari SH Hard Disk Drive Owner's Manual C026263 Rev B.pdf.
- ↑ Photograph of the rear panel of a European SH204, atari-computermuseum.de. File:Atari SH204 rear panel (Atari Computermuseum).jpg.
- ↑ 6.0 6.1 SH Hard Disk Drive Owner's Manual, chapter 2, Notes and Warnings, p. 18 (PDF p. 24).
- ↑ Atari Corporation, MEGAFILE Hard Disk Drive Owner's Manual, C300459-001 Rev. B, 1988, chapter 1, Connecting Additional Hard Disk Drives, PDF p. 10. File:Atari Megafile Owner's Manual C300459-001 Rev B.pdf.
- ↑ 8.0 8.1 8.2 SH Hard Disk Drive Owner's Manual, appendix B, Controller Command Summary and Command Operation Codes, pp. 25-26 (PDF pp. 31-32).
- ↑ SH Hard Disk Drive Owner's Manual, chapter 2, Running HDX.PRG, pp. 11-16 (PDF pp. 17-22).
- ↑ 10.0 10.1 Atari (Japan) Corporation, Host Adapter Card Schematic Diagram, drawing C026198. File:Atari SH204 Host Adapter Card Schematic C026198.pdf.
- ↑ Photograph of the SH204 disk controller board, atari-computermuseum.de. File:Atari SH204 disk controller board (Atari Computermuseum).jpg.
- ↑ Photograph of the inside of an SH204, atari-computermuseum.de. File:Atari SH204 interior (Atari Computermuseum).jpg.
- ↑ Gregg Anderson, "Massaging Your MegaFile", ANALOG Computing issue 79, December 1989, p. 114. https://www.atarimagazines.com/analog/issue79/megafile.php
- ↑ "Just got a new SH204 minus the hard drive", exxos's Atari, Amiga & retro forum, January 2019, post by tzok of 9 January 2019. https://www.exxosforum.co.uk/forum/viewtopic.php?t=1533. Community report.
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