Up for sale is a complete, vintage Hewlett-Packard HP 48GX graphing calculator kit. This premium bundle is perfect for engineers, collectors, or students looking for a reliable RPN powerhouse paired with rare companion manuals.

📦 What's Included:

• HP 48GX Calculator (128K RAM Main Unit)

• Original HP Protective Slipcase (Textured gray)

• Book 1: "Graphics on the HP 48G/GX" by R. Ray Depew (Grapevine Publications)

• Book 2: "Algebra and Pre-Calculus on the HP 48G/GX" by Dan Coffin (Grapevine Publications)

🛠️ Working Condition & Diagnostics:

• COMPLETE HARDWARE DIAGNOSTICS PASSED: This calculator has been fully bench-tested using HP's built-in factory self-test suite. It successfully cycled through and passed all internal checks, including the Internal ROM, IRAM/RAM memory registers, the interactive multi-pattern matrix graph display loop, and the individual key-by-key matrix board verification. The screen outputs the official "HP48-OK" system status upon completion.

• INFRARED PORT VERIFIED WORKING: This calculator has been fully tested over-the-air with a vintage HP 82240 infrared thermal printer. It seamlessly connects, transmits data wirelessly, and prints without lag or signal dropout. (Please note: The HP 82240 printer was used for verification testing only and is NOT included in this listing).

• EXPANSION CARD SLOTS: Both Card Slot 1 and Card Slot 2 have been physically tested and verified. They cleanly interface, detect, and securely read/write external memory expansion and application cards without errors. (Please note: Expansion cards were used for verification testing only and are NOT included in this listing).

• All key layout domes snap cleanly with flawless tactile registration. The battery terminal contacts are clear and completely free of acid corrosion.

🔍 Cosmetic Condition Notes (Please Read):

• Calculator Screen: There are multiple noticeable scratches across the screen area, text, numbers, and graph pixels remain fully sharp, unblocked, and clear to read when powered on.

• LCD Background: True to peak-era 90s STN displays, a mild background refresh shimmer can be observed if the screen contrast is maxed out. The hardware contrast has been calibrated manually to its factory sweet spot to provide a solid, flicker-free background.

• Calculator Body & Bezel: The chassis is structurally sound but shows typical cosmetic wear from field and desk use. The reverse matte plastic casing has minor shelf wear with one small noticeable scratch on the back panel. Additionally, the light gray display bezel border has several small dings and cosmetic indentations along its perimeter. One of the small rubber non-slip feet on the bottom of the device is missing.

• Battery compartment: The battery compartment is in otherwise pristine condition, except for one small area of light surface corrosion on the far-right contact. All battery contacts have been completely cleaned with rubbing alcohol and treated with professional-grade DeoxIT D100L to ensure excellent electrical conductivity and protect against future oxidation

• Companion Books: Both out-of-print manuals are included. Please note that the "Graphics on the HP 48G/GX" book has a heavily compromised/split spine binding with multiple loose and detached pages.