20 Most Recent Fender Hot Rod Deluxe Guitar Combo Amplifier - Page 3 Questions & Answers

Replace diodes CR6 through CR9 and test C31 and C33 for short. If all OK and fuse still blows, remove the power tubes and test. Hopefully you do not have a transformer short.

To save fuses, put a 150 watt light bulb in series to act as a reseting fuse while testing.

Look at your indicator LED... is it off for the clean? Does it show yellow for drive and red for more?
Depending on if this LED is showing these correctely tells me where to look for problem. If the LED shows these correctely, then problem is with the relays that do the switching or a few transistors that change the gains for the drive and more functions.

Do you turn on standby every time and wait for the tubes to heat up first? If you don't, it can severely damage the tubes.
But a common cause of this could be just old tubes. Like any other piece of technology, tubes get old. If you like to play your amp LOUD then they wear out a lot quicker. You have to replace tubes every now and then. Because I'm not there to check out your amp, I can't give you an exact answer but it sounds like that's the problem. This isn't always a bad thing. You can make the sound of your amp exponentially better with nicer, new tubes. Your amp has 12AX7 tubes. Very common tubes to use actually. I'm not sure what kind of music you play, I'm assuming mostly rock and blues. But here is a list of tubes and reviews on them.
http://thetubestore.com/12ax7review.html
This is how to replace a tube:
http://www.ehow.com/video_4438285_change-pre_amp-tubes-guitar-amps.html
Upkeep on a tube amp:
http://www.ehow.com/video_4438295_replace-tubes-guitar-amp.html
A note he doesn't make in the video is to dust out your amp. I use the compressed dust spray for the inside of computers.
So overall, stop turning up your amp to 11, make sure it's well ventilated and dust it out from time to time. Hope this helped.

I have worked on a number of these amps and found the most common cause of intermittent channel switching is dry joints on the foot switch jack or the contacts becoming contaminated. In either case you will require a tech to look at your problem as the main board will require being lifted out of the metal chassis for inspection. Because of the ribbon type cables between main board and the board that supports all the valves I recommend professional help . Not a DIY job

If the footswitch is not switching correctly, open it up and check for any shorts or a defective switch. Sounds like it's a problem with the switch.

There are only TWO op-amps and the tank involved with the reverb. Both of those are in one IC chip labeled "U2". It is a TL072.

Pin 1 of that chip is the output to the tank and pin 7 is the inout of the reverb control pot that then goes into the power amp.

They resistively mix the delayed reverb signal with the straight signal at the input of the power amp.

I assume you have turned up the reverb control which is just a volume control for the signal going through the tank.

There are so few parts involved with this that a failure is really rare.

Your reverb spring is most likely broken. If it has electronic reverb, then the chip has gone out. For both of these problems, a qualified amplifier technician will have to look at it and replace the parts.


Hope that helps! Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/cameron_463100ffd54b591d

Why did you replace the fuse? If it was blown then you need to take the amp in for servicing. Iffthe fuse is glass and it was silvery on the inside, that is a hard short and is likely a power supply problem. Probably a rectifier diode or filter cap. Pray that it isn't the power transformer. Diodes are cheap... few pennies... caps a few bucks at most. Power transformer... you DO NOT want to know.

What is the problem

voltometer may help.

Unless the person that analyzed this problem used an oscilloscope and did detailed troubleshooting, I would NOT jump to the conclusion that aan op amp was blown BASED upon my looking at the schematic of the unit. There are MANY components involved with the overdrive channel, including relays and other transistors and components. The most probable caause would be that 1/2 of the V2 vacuum tube is burnt out. Test by swapping V1 with V2. If NOTHING works, then replace the tube that is NOW in V1 as the second section of it has a burnt out heater. Also a bad potentiometer for the OD channel would be a suspect. A VERY common problem is broken solder at pot terminals. Try plugging a set of headphones into the preamp output. See if you can hear sounds in bothe OD and clean channels. Note you will only hear sound in the LEFT headphone as the preamp out is MONO. MOST of the three op amp chips would NOT kill the OD signal if they were bad.