Commodore 128 Diagnostic Cartridge with Voltmeter

• Digital Voltmeter: Built-in real-time LED display monitors the critical +5V rail directly from the cartridge port to safeguard your vintage IC chips.
• Precision Diagnostics: Runs full Commodore 128 factory diagnostic tests, verifying SRAM, DRAM, CPU, CIA, VIC-II, VDC, and SID capabilities.
• Pure C128 Mode: Operates natively in C128 mode, supporting both 40-column (VIC-II) and 80-column (VDC) video output paths.
• Plug & Play: No external power or setup required—simply plug into the expansion port and boot up your system.

Advanced Hardware Diagnostic & Safety Tool for Commodore 128 / 128D

Is your Commodore 128 displaying intermittent memory errors, strange video glitches, or refusing to boot into 128 mode? The Commodore 128 Diagnostic Cartridge with integrated Voltmeter is an essential instrument for every hardware enthusiast, collector, and restorer. This cartridge lets you instantly isolate system faults while keeping a vigilant eye on the health of your vintage system's power delivery.

Integrated Digital Voltage Monitoring

The single most common cause of catastrophic component failure in vintage Commodore equipment is failing original power supplies. As original transformers age, their internal regulation circuits degrade, often outputting dangerously high voltages (over 6V or 7V) on the +5V line, which will quickly fry hard-to-replace chips. Our custom cartridge board includes an ultra-bright, real-time digital LED voltmeter. It samples system voltage directly from the expansion port, allowing you to instantly catch power supply issues before they can damage your motherboard ICs.

Comprehensive C128 System Diagnostics

This premium tool is preloaded with the official, full-featured Commodore 128 diagnostic program. When inserted and powered up, the cartridge bypasses corrupt operating system subroutines and executes a series of hardware verification loops:

• RAM Testing: Pinpoints faulty DRAM/SRAM bank chips, identifying the exact physical chips required for repair.
• Internal Controller Audits: Evaluates CIA 6526 logic, PLA configurations, CPU operation, and MMU functionality.
• Audio & Graphics: Tests SID waveform generation, VIC-II (40-column) output, and the high-speed VDC (80-column) video controller memory system.

Compatibility & System Support

• Compatible with both PAL and NTSC Commodore 128 (flat/desktop) and Commodore 128D (integrated keyboard/disk drive) models.
• Fits perfectly into original standard expansion ports without case interference.
• Runs exclusively in native 128 mode (bypasses Commodore 64 mode routines to ensure 100% accurate 128-specific chip evaluation).
• Designed using high-quality components, low-power modern logic, and thick gold-plated edge contacts for exceptional longevity.