Did KF ever publish his amp troubleshooting algorithm ?

[chopstuck]

I had read that he had a way to fix things quickly by following an algorithm. I could really use that as I have about 6-8 amps I haven't gotten around to fixing because it just takes me forever.

[benoit]

I think Jack Darr's book had a troubleshooting alg.

[chopstuck]

Yea, I've got that one. I was just looking for the "Super deluxe quick guide, for parents of young children that can't be left alone for more than five minutes without re-texturing a domestic surface, guide to Amp repair - (Executive version).

[rfgordon]

I feel your pain, man. I've gotten better at troubleshooting over the past couple of years, but I'd have to say that there's way more good info out there on building amps than fixing them.

[Jana]

I think the first step that must be achieved is an understanding of how tubes function and what the parts do. It isn't all that difficult to clone another amp, especially if you have pictures showing where the wires go, etc. This is the "how to do it." Quite a bit different than the "why to do it."

I would emphasize that any one who wants to really "become one" with the amps they build to tinker and experiment with the goal of understanding not only of a functional purpose, but a musical purpose, of the parts in an amp.

The nice thing about most guitar amps is that they are really pretty basic .. Three simple sections, power supply, power amp, preamp. It's a matter of cutting the area of the problem down until you find it. All this presumes an amp that once worked but had a failure. A new build is more involved because you aren't really sure that the build is at fault or a bad part. The process is similar, however.

I suppose the bottom line is that you have an understanding of what should be happening in the circuit and what is really happening.

Then, after about 20 or 30 years of tinkering with guitar amps and you get confident in your abilities, the universe will throw a problem your way that will really humble you.

[chopstuck]

Very Zen. Feel the thermionic emission....

Seriously I forgot the old basic mantra.

Never trust a ground connection until verified by a high tech alligator clip to ground and a probe. If you tap it and it makes noise. It's not a good ground.
Saved my ass again. Measuring with a Vom just doesn't cut the mustard

Visualize the Bohr cloud of particles to surround your head, though careful not to allow conduction through the foot firmly on the ground .
Always insulate.


-Dr Kasey Kasim

[Andy Le Blanc]

an amp is a power supply attached to a speaker......
and after a while you can tell what was cooked by the way it smells......

[chopstuck]

I didn't mean to be flip but since KF noted he found a way to diagnose and repair amps quickly that was so much more profitable, than building amps from scratch, that some one might have had an inkling on how he did it.

I'm familiar with starting at the PS and working toward the preamp and correcting things as I go along. All I end up doing is spending time fixing non-issues until I get to the root problem. This usually occurs hours later and after many back and forth trips to the garage- basement- internet- repeat. So I thought someone else may have an algorithm that is efficient, or more so than I am. Wouldn't take much.

[Normster]

No algorhytm here, but this is really a worthy topic. We have all probably picked up little trick along the way that would be great to get into one place. Maybe start a "diagnosis by symptom" list as well as a "good health checkup" routine.

[Stanz]

To be fair, not much to trouble shoot, at least for getting an amp back to working condition. Once you understand the basic workings of most amps, whatever symptoms are displayed should get you pointed to the trouble area pretty quick. As for fine tuning amps, that is a whole other level of understanding.

[Ears]

An algorithm of a kind here

http://www.geofex.com/

follow your nose through Tech pages -> tube amp debugging

[chopstuck]

Thank you. Will do.


So many amps, so few cords....

[km6xz]

This post is quite surprising to me. Building an amp well is a lot of work. Repairing an amp is usually very simple and fast. If a tech can't diagnose and have the mechanism of fault determined in 30 minutes, he is not much of a tech. He might be a great constructor or musician but he is not a tech. It might take a lot longer to actually do the repair but that is easy, just time consuming. The skill is in diagnostics, the labor is in building or doing the repair after diagnosis.
If you have a pile of amps that need work, why risk further damage to them or to yourself if you are not skilled in it? Find a qualified tech and pay him to walk you through a typical diagnosis and repair. But before that, read up on basic electronics and become familiar with the concepts and basic circuit topography.
There is a reason why there are very few good techs however, it takes too long to learn the wide range of technologies involved. Any other career would yield higher benefits from a lot less work and experience as needed to be effective and competent.
Of ALL electronics, tube amps are quite likely to be the easiest for a beginner to grasp however. Your hi-fi or Walkman recorder both have 10 times the complexity of cirsuits and technologies.
A good tech who is not an ego head trip would love to pass on their insights to an interested and motivated student. They get lots of questions but few people what to really know the details or put in the energy and time to be competent in their craft.

To even consider repairing a variety of amps, have competent test instruments on hand before attempting diagnostics. Without them you are only guessing and that can damage an amp as likely as your stumbling on a repair. Finding a defect is only part of the problem, figuring our the mechanism of fault is the most important requirement, that is, finding out why the defect occured, what chain of events resulted in the defect. A burned resistor is easy to find, but being fully confident in determining what circuit conditions caused the symptom of a smoking resistor is not as easy and separates techs from laborers. The charred resisitor is not the defect, it is an indicator, or symptom, of a fault somewhere else. Replacing a burned resistor alone only guarantees further smoke.

Good luck with your project.