Sooner or later, it happens to every active ham -- something in your station breaks, sometimes rather spectacularly!    An important part of amateur radio is the ability to troubleshoot and fix station equiment when needed.  This skill is used to great effect under emergency conditions, when you can get systems up and running while the commercial services may take weeks to make a repair.  Fixing equipment can be an effective way to learn about electronics.  Over the years, ARRL authors have written a number of excellent articles about electronic troubleshooting that give the fundamentals and the fine points of equipment repair.

• Troubleshooting Your Radio Equipment
  QST November 1993, pp. 65-66
  Troubleshooting your equipment is easier than you think.
• Electronic Troubleshooting -- Lab Notes
  QST November 1995, pp. 87-88
• Some Basics For Equipment Servicing -- Part 1
  QST December 1981, pp. 11-14
  Costly repairs to amateur equipment can often be avoided if we do our own repair work. Knowing the nature of semiconductors is a vital means to that end.
• Some Basics For Equipment Servicing -- Part 2
  QST January 1982, pp. 38-41
  Dc voltage measurements are fundamental to troubleshooting amateur equipment. We'll look at how to make these measurements and show you a "hi-Z" voltmeter you can build in a weekend.
• Some Basics For Equipment Servicing -- Part 3
  QST February 1982, pp. 40-44
  Using the proper techniques can speed equipment servicing. The methods are easy, and you can build the test gear!
• Some Basics For Equipment Servicing -- Part 4
  QST March 1982, pp. 40-44
  Knowing how to use the oscilloscope effectively as a troubleshooting tool will move you to the front of the equipment servicing class.
• Testing A Sideband Transmitter
  QST September 1965, pp. 14-18
  A primer of simple tests and adjustments.
  (This article is for those servicing vintage transmitters from the mid ‘60s and ‘70s. -Ed.)
• FT-101 Power Amplifier Valves from Ham Radio Today (RSGB) April 1998
  Beware of changing the 6JS6C power amplifier valves in the venerable old FT-101 (this applies to direct replacement without circuit modification)

•  Amplifier Care and Maintenance Sep 2003 - QST (Pg. 33)
  How to safely service tube type amplifiers with high voltage power supplies.

• Eham Reviews of companies that repair radios.
• Sci.Electronics.Repair FAQ
  This site features a series of comprehensive repair guides for consumer electronics equipment and other household devices. There is also a great deal of other information of interest to the electronics hobbyist, experimenter, technician, and engineer.
• Schematics of radios.
• Colin McCord's web site has lots of good information on oscilloscopes.
• We also have a page on building test equipment.