Very Technical Information about PC internals and Peripherals

How to Read Capacitor Codes
Diagram and explanations

How to Read Resistor Codes
Learn how to tell tolerance band, from multiplier, etc.

Pinouts (http://pinouts.ru/cgi-bin/view_filt.cgi)
almost a 1000 of various cable and connector pinouts

Hardwarebook (http://www.hardwarebook.net/)
Internet's largest free collection of connector pinouts and cable descriptions.

The Circuits Archive (http://www.ee.washington.edu/circuit_archive/text/)
Connectors, pinouts, codes and other info

pin-outs.com (http://www.pin-outs.com/)
Cables, Pinouts and Connectors

GamesX (http://www.gamesx.com/)
Pinouts to videogames

The Technician's Guide to PC Hard Disk Subsystems (http://www.actionfront.com/tech1.html)
by Nicholas Majors of Data Recovery Labs is an excellent piece of work. Originally geared toward tech support personnel, but of much wider interest, it discusses history, principles, installation and configuration in a lucid no-nonsense style. Includes glossary and references.

The Archive of video terminal information (http://www.cs.utk.edu/~shuford/terminal_index.html)
Character-cell video-display terminals, serial-line remote-graphics terminals, and software that emulates them.

Chip Directory (http://www.xs4all.nl/~ganswijk/chipdir/)
Pinouts to Integrated Circuits, etc

Tomi Engdahl's Electronics Pages (http://www.tkk.fi/Misc/Electronics/)
Useful electronics information collections

PC Hardware Link Page (http://webpages.charter.net/dperr/pc_hdwe.htm)
Various Links and some own PC Hardware info

Electronics basics (http://www.epanorama.net/links/basics.html)
Teaches how to build electronics

Networking Cabling Pinouts

BIOS Tone POST Codes

PC And PS2 POST ERROR CODES

Standard PC storage devices and I/O connector pinouts.

Standard PC Cabling Pin-out Diagrams

PCB Design (http://www.smps.us/pcb-design.html)
PCB (printed circuit board) design and assembly: free software, layout guidelines, trace calculators, tutorials, standards, tips, free cad program downloads. Includes manufacturing and prototyping guides and other info and resources.

Sci.Electronics.Repair FAQ (http://www.repairfaq.org/REPAIR/F_Repair.html)
Represents a unique resource in the Universe providing information on a variety of topics including consumer electronics repair, general electronics, and lasers and optics.

Electronic circuits (http://www.electronic-circuits-diagrams.com/)
Electronic circuits, kits, do-it-yourself, circuit diagrams, design and electronics hobby schematics

alt.comp.hardware.homebuilt (http://www.faqs.org/faqs/homebuilt-comp-FAQ/)
Frequently asked questions (FAQ) and general information pertaining to the newsgroup alt.comp.hardware.homebuilt

Total hardware - jumper settings (http://th99.too.it/)
Jumper settings for about 20,000 devices

Circuit Sage (http://www.circuitsage.com/)
A complete source of information to help you design great circuits fast

Electronics Engineering - Knowledge Bases (http://www.compinfo-center.com/micro/electronic_engineering.htm)
A collection of links to electronic components, circuits, cables, etc.