1541 Diagnostic Cartridge (World of Jani) – Test and Repair for Commodore Disk Drives

A Complete Service Toolset in One Cartridge

The diagnostic cartridge for the Commodore 1541 disk drive is an indispensable tool for anyone repairing, maintaining, or simply checking the condition of their drive. The software, authored by Jani Tahvanainen (World of Jani), is designed to run directly from the C64/C128 expansion port – with no need to load anything from a diskette. This is a key advantage: the drive being tested does not need to be functional at all to initiate diagnostics.

What Can You Find in the Cartridge Menu?

• Alignment Check – Quick evaluation of the read/write head alignment
• Speed Check / Performance Test – Measurement and control of motor rotation speed (correct value: 300 RPM)
• Head Exerciser – Forced movement of the head across all tracks, helpful for dried-up lubricant in the mechanism
• Error Scan – Scanning the diskette for read and write errors
• Validate Disk – Validation of disk structure and integrity
• View BAM, Sector View, Directory – Low-level view of media content bypassing standard DOS
• Fast Format – Quick test formatting of diskettes
• Disk Command, Send IO, Reverse Knock – Advanced tools for direct communication with the drive's control electronics

Who Is It For?

Perfect for both professional technicians working on retro hardware repairs and hobbyists who want to diagnose drive problems themselves – from suspected head misalignment, through unstable rotation speed, to diskette read errors.

Compatibility

Compatible with Commodore 64, C64C, C128, C128D, and C128DCR.

Technical Specifications

• Format: 8K ROM cartridge (optimized to not overwrite the BASIC interpreter)
• Cartridge casing available in a palette of over 30 filaments.

Project:
http://blog.worldofjani.com/?p=2180