HP-85 Restorations

Project Top

Table of Contents

• Introduction
• Tools and Materials
  • Tools
  • Materials
• Seiko Paper
• Keyboard Plungers
  • Background
  • Series80 Forum Posts about Keyboard Plungers
  • Three types of Keyboard Plungers
  • Removing Plungers from the Keyboard (Success)
• White Plungers
  • Repairing the White Plungers with glue (Failure)
  • HiTek Plungers repair Overview
  • Machining the Plunger Corners (Failure)
  • Trimming the Plunger Corners (Success)
  • Material #1: Copper foil (Failure)
  • Material #2: Kapton tape (Failure)
  • Material #3: Melted Nylon (Failure)
  • Material #4: Glide Dental Floss (success)
  • Repairing with Plumbers Tape (unknown)
  • Repairing with Brass Shim Girdle (success)
• Green Plungers
  • Green Stackpole Plungers Modification Overview
  • Green Stackpole Plungers Cutting the Tab
  • Green Stackpole Plungers Making the Sleeve
  • Green Stackpole Plungers Gluing the Sleeve and Tab(s)
• Tape Drive Capstan
• Videos
• HP85 I/O Bus Timing
  • Delays through 1MA8
  • Write Cycle as seen on the I/O bus
  • Address Cycle as seen on the I/O bus
  • Other Timing Measurements
  • Detailed instruction Fetch and Execute
  • Oscilloscope screen captures

Indices and tables

• Index

• Search Page