Loud hum with no guitar coming through - Crate Music

You have a bad ground somewhere. Try different cables and check the effect channel port if it is tight and secured.

On mine, the guitar input jacks get tarnished and causes all kind of interference and noise. Take a Q-Tip soaked with WD-40, run in down into the jack and brush up and down. Don't overlook the filter caps as they are a common cause of noise. You need a capacitor checker (the older tube type) to thourghly check those out.

try plugging into a different socket if that doesnt solve problem you may need to replace cord. sounds like a loose neutral in socket though.

Simple answer is yes.

Power amp chip or transistor has shorted to one of the power supply rails. Do not use until repaired as it is likely driving high DC current into the speaker.

Unplug the inputs to the amp. If hum disappears, then you need to fix the guitar or the cable or keep the guitar from magnetic fields which are present near amps and other powered equipment. Use of Humbucker pickups helps a lot. If amp has objectionable hum with inouts unplugged, take it in for repair.

i) Disconnect one lead of loudspeaker & insert an open-ended guitar cable into headphone socket.

ii) Put a dc voltmeter across open end jack then turn Frontman ON for a few seconds.

iii) The reading should be about 0volts - if the voltage is high (27v), then it is likely that the PA chip TDA1514A has blown.

iv) If,however, the voltage is correct in iii) , then reconnect speaker & put guitar cable into the POWER AMP IN socket & connect other end to guitar...Turn on briefly, if there is still hum then fault is in the output stages & will require chassis removal to solve.

OK... Most of the guitars have a PAINTED on shielding in the well with the electronics. Sometimes the electrical connection to this is broken causing hum. Sometimes the connection is by way of the potentiometer shaft nuts and they spin and break the connection. This paint is conductive and often black know as aquadag. Use an ohmeter to verify connection.

If you unplug the guitar cable and STILL get the hum, the unit has a defect... return under warranty.

If the hum goes away when you unplug the cable, replace the cable and see if new cable fixes the problem. If it does, the cable has a bad shield.

If the cable didn't cure it, then the guitar has a defect. Remember that some guitar pickups are sensitive to the magnetic fields from the amps... only cure is to either use humbucker types or be a distance away from the amp.

I would also be inclined to check all the larger electrolytic capacitors in the power circuits as well for AC bleed.