Trouble Shooters Chart




Absence Of Signals
* Burnt out rectifier valve
* Broken down filter capacitors
* Open-circuit field winding or filter choke
* Short in H.T. by-pass capacitors
* Open circuit cathode resistors
* H.T. supply line open circuit
* Open circuit R.F. or I.F Coil
* Shield can shorting to grid cap
* Disconnected wiring
* Faulty valve socket or speaker connection
* Low B+ Voltage

Poor Volume
* Weak valves
* Low H.T. or filament voltage
* Poor alignment
* Open circuit R.F. or I.F. coils
* Faulty volume control
* Incorrect valve types
* Leaky high voltage caps

Distortion
* Open circuit bias or grid resistors
* Audio feedback
* Low emission valves
* Incorrect voltages
* Leaky coupling capacitors
* Gassy output valve

Crackles And Whistles
* Faulty resistors
* Faulty capacitors
* Loose contacts at sockets
* Dry joints
* Faulty output transformer
* Faulty power transformer
* Ineffective valve shield( Whistles in particular)
* Faulty valve
* Poor wiring layout
* Poor alignment

Hum
* Poor filtering
* Short between cathode & heater
* Poor shielding on audio leads
* Bad rectifier
* Faulty electrolytic capacitor

Severe Hum
* Shorting electrolytic capacitor
* Internal fault in rectifier
* Shorted field coil or H.T. choke

No Shortwave reception
* Dirty wave change switch
* Resistors high in R.F. stages
* Weak frequency changer valve
* Low H.T. voltage

Low High tension
* Weak rectifier valve
* Faulty power transformer
* Incorrect speaker
* Faulty valve

Rectifier glowing red
*Direct short on H.T. Line. (e.g. Electro filters)

Output valve red
* Open circuit anode on output valve
* Open circuit output transformer
* Speaker unplugged