The Restoration of the PDP-8/I Minicomputer (PAGE 1)

I received my PDP-8/I from a gentleman in Mississippi on Wednesday, June 4th, 2003 (20030604). It came in a nice rack, and was in excellent physical condition. This webpage chronicles my restoration of the 8/I. As of Tuesday, December 16th, 2003 (20031216) the machine is in a "all known problems fixed" state. And, two days later, I played chess on it! :-) So, I'd say it's now restored!!!

Table of Contents:

• Capacitor Reformation -- 2003 06 08
• Test +5 VDC Regulator -- 2003 06 08
• Basic Powerup
• Repair Front Panel -- 2003 06 09 - 2003 06 10
• The Mystery of the Deposit Command -- 2003 06 10
• Another Dead 7474 -- 2003 06 30
• Current Status 2003 07 06
• Power Supply Troubles -- 2003 07 09
• The Mighty Hunter Returns with Capacitors -- 2003 07 12
• First Successful Program! -- 2003 11 05
• Rotate Problems Fixed -- 2003 11 10
• Manufactured W076 TTY (RS232) Interface Card -- 2003 11 22
• Front Panel Bulbs and Transistors Repaired -- 2003 11 23
• TTY Output! -- 2003 11 23
• Game Over Core Dead -- 2003 11 24
• IOT and JMS lights on for IOT -- 2003 11 24
• Diagnosis of the EAE (KE8I) -- 2003 12 05
• The Mind Boggles -- 2003 12 08
• TTY Input -- 2003 12 10
• Fixed (bad 7474 chip, bad 2N3009) -- 2003 12 15
• 2nd bank of 4k installed and tested -- 2004 01 19

Also, here's a link to the test programs page.

Current Score

The current score is eight dead chips, and four dead transistors:

Part #	Date Code	Manufacturer	Card
7474	6908	Sprague	M216
7474	6919	National Semiconductor	M220
7453	6939	National Semiconductor	M220
7474	6931	National Semiconductor	M220
7474	6929	National Semiconductor	M220
2N3009	?	?	M220
2 x DEC -2	?	?	Front Panel
7410	6912	Texas Instruments	M115
7440	6932	Sprague	M220
7474	7233	National Semiconductor	M706
2N3009	?	?	M310

Wishlist

I'm currently looking for some spare parts...

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