'slow blow' or 'time delay' 1/4 inch (6mm) wide by 1 1/4 inch (30mm) long. Mains fuse holder on the control panel or on the back of the amp chassis Problem is probably with a blown fuse or the power supply. A blown bulb will not showДЄny heater glow (dimming the room lights can help you see the tube glow) the Using a multimeter's continuity or 'beep' function. Light you can remove the bulb and test it for continuity across the bulb terminals Shows signs of life but does not put out any guitar audio. Little and touch the tip of the guitar cable's other end. Guitar cable, turn up all the amp's volume, gain and master volume controls up a Suspect a bad tube, blown fuse or the power supply in that order. Silent (no speaker hum or hiss at all) then the problem can be just about anywhere in the amp but you should The amp powers up but the guitar audio sounds weak, bad The amp powers up but makes weird noises likes squeals, oscillation, static or Lights are on or you can hear speaker hiss. The amp shows signs of life but does not put out any

Try another guitar, guitar cable, speaker and speaker cable.ДЄ speaker or dummy load is connected to the amp every time it is powered up. To popular belief, the power and output transformers are the least likely cause of amp Play through the VibratoД¬hannel and test the amp after every tube swap. Other small tubes in the amp to find a bad tube. SeeДЇender 1960 and newer two channel amplifiers the first tube on the right, V1, isДЇor the Normal channel only and can be pulled out and used to replace all the Inserting it into the socket a couple of times. You can clean the socket by spraying contact cleaner on a tube's pins and Sometimes you can gently wiggle a tube and listen for Normal plate voltage, zero voltage on the cathode of a cathode biasedДЄmp-almost anything. Pop, weakening or thinning of signal output, loss of tube heat, higher than Problems including complete loss of signal, red plating due to loss of bias Or dirty tube socket pins can cause all kinds of hard to diagnose intermittent Their plates and die quicker than preamp tubes. Rectifier tube-they can cause all kinds of problems including weird noises. Morghulis,' 'all tubes must die.' Don't forget to try a new Power tubes usually wear out quicker than preamp tubes but as they say, 'tubular Including everything from complete signal loss, hum, hiss, static to something A bad tube can cause lots of different symptoms Having a spare set of tubes to swap into the amp one at a time is a must for Suspect a bad tube as they are the most common failure point in a tubeДЄmplifier. Power tube increase so this isn't a hard-and-fast rule. Does a volume, tone or master volume control affect the noise? WhenДЄ control affects the noise it usually indicates the noise is entering the ampД«efore that control but I have seen a volume control that caused noise in a bad You mustД«efore doing any work inside an amplifier chassis. Use just one hand when working on a powered amp. Lethal shock can run between your arms through your heart. Never touch theДЄmplifier chassis with one hand while probing with the other hand because a High voltage then have an amp technician service your amp. If you have not been trained to work with

Tube amplifier chassisВ contains lethal high voltage even when unplugged-sometimes They are to troubleshoot, so keep learning. You know about how tube amps work the easier Following it will minimize damage due to a miswired amp. Many of these techniquesДЄre turning on a new build amp or heavily repaired/modified amp for the first time I recommend you use a

Technique for troubleshooting a tube guitar amplifier.

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