You have an overload in either the power supply section or Main amp section. Culprits in the power supply are the transformer, the Large Capacitors, rectifier, voltage regulator. In the Main amp anything on the heat sink. Look carefully for burnt or damaged parts. If there's more than one fuse, follow the path of the one that is blowing it might lead you to the suspect.
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You have an overload in either the power supply section or Main amp section. Culprits in the power supply are the transformer, the Large Capacitors, rectifier, voltage regulator.
In the Main amp anything on the heat sink.
Look carefully for burnt or damaged parts. If there's more than one fuse, follow the path of the one that is blowing it might lead you to the suspect.