variable bias versus fixed bias guitar amp

If the capacitors look good, I will still check the electrolytic capacitors and the audio decoupling capacitor (especially this one). I go straight to the capacitors, and if they are in poor condition, I will often replace all the paper capacitors and electrolytic capacitors, even before powering a radio up. I usually don't bother to even check the valves. Most faults are due to capacitors, particularly filter capacitors, bypass capacitors, and coupling capacitors. Valves account for less than 10% of faults. This is very interesting and useful, but it applies to near-new radios that were in use at that time and failed. There is a histogram from Radio and Hobbies that shows the common faults in 1959. The radio may have failed in 1950 and been put on a shelf, so you may possibly have several faults, the original one, and the age effects. However, the radio is now over 50 years old, and age will affect many parts, so age effects will need to be corrected first. If it was the year 1950 and your near-new radio has stopped, you would look for a failed component. The faults can be loosely categorised in two groups. YOU MUST NOT ATTEMPT TO REPAIR THE RADIO YOURSELF UNLESS YOU ARE LEGALLY ALLOWED TO DO SO. This is why any electrical work to restore or repair an old radio must be done by a licensed qualified technician. Many types of early consumer electronic equipment was constructed at a time when electrical safety was not as carefully considered as is required under manufacturing laws today, and many early radio sets etc have mains electricity wiring and metal mains voltage terminals fully exposed to be touched once the metal chassis is removed from the wooden case or bakelite housing. Any electric shock at Voltage 110v or above is likely to be lethal. The United Kingdom and Australia (amongst many other countries) uses 240 volts AC. If you are not lawfully allowed to repair electrical equipment yourself, you must find an electrician, a licensed electrical mechanic or electrical contractor or electronic technician to do any work on the equipment.ĭifferent countries use electricity supply at different voltages. This is to protect the public from the risk of electric shock. Radio Servicing Information For use by legally qualified and licensed repairers onlyĬountries have laws regulating who is legally allowed to repair or work on electrical equipment that will be plugged into the mains electricity supply.

Variable bias versus fixed bias guitar amp