If there is a total lack of sound coming from the amplifier and the power indicator is lit, you know that the amplifier is receiving electricity, but something is blocking the signal path. This is probably due to burnt filaments in the tube of the amp. If the filaments do not light up at all, you need to replace the tubes. If the power indicator is not lit, you probably have a blown fuse, faulty switch, or a worn cable.
Listen to any noise or lift coming from the amplifier. This is an indication of a fault in the lower signal sections of the amplifier, such as the preamplifier tube or the preamplifier power. These parts are interchangeable and should be relatively inexpensive. Also check dirty inputs and incorrect signal cable. If you do not know what your management should look like, see your owner’s manual for a chart.
Note any screaming sounds you hear from the amplifier. The most common reason for this is that a tube becomes microphone. Try to replace the pipes. If the amplifier stops constantly, as opposed to only when you hit a note, the first preamp tube is probably faulty. Other causes of screaming include poor contact in the input socket, incorrect polarity of a replacement output transformer or incorrect grounding in a new amp modification.
Check for any defects or tears in the speaker cone and replace the speaker if you find any unwanted distortion. This is probably the case if the amp sounds hard and grainy. This type of sound can also be due to output hoses that are biased too cold. If the sound is muted, a number of problems can occur: a faulty front tube, poor coupling capacitors, poor plate resistance, or a power supply problem.
Check any manufacturing defects immediately after purchasing your amp. Some buyers report problems such as malfunctioning base buttons on a brand new amplifier. Do not try to repair such problems yourself. Contact Fender instead for a full refund or replacement.
Tips and warnings
The Fender Super Sonic 112 Combo Amp is a 60-watt all-tube guitar amplifier. The amp has a variety of vintage and burn channels, spring conservator, dual cascading-gain preamp overdrive and a single 12-inch Celestion Vintage 30 8-ohm speaker. Despite these many features, the Super Sonic amplifier may be prone to repair problems like any guitar amplifier.