decent how-to guide to learn electronics repairs?

[dissonantdissident]

Hey there TapeOp!

So, I've got an ashly comp pooping out on me, and I really feel like I should be able to fix it(with the skils from all of the mic mods I've done) but I don't really know where to start. It fires up, but after it's been on for about 10 minutes, the vca totally clamps down and nothing passes. I have a feeling something is failing as it reaches operating temp. I'm sure I could replace the parts, if I could isolate the problem component(s). Any suggestions for a decent book to learn the basics of repair would be appreciated.

glenn

[terryb]

I don't know of any books that will help, but my approach would be to find a schematic of the circuit, build an audio probe(super simple), and then probe the circuit point-to-point from input onward until i found where the failure is happening.

[The Scum]

SAMS publishing used to print these repair guides..."How to repair HiFi," "VCR," etc. They're mostly trash, so don't go too far out if your way thinking one of those is what you're looking for.

Bob Pease's "Troubleshooting Analog Electronics" is hugely valuable and informative. Also more encompassing than any single discipline.

If you're serious about learning this, consider getting some of the right tools. A real oscilloscope is at the top of the list. You need to be able to quickly check both AC and DC voltages while troubleshooting.

A service manual is also very useful. A good service manual will have some explanation of how things work, and where to begin when troubleshooting. A schematic is better than nothing.

If it's a 2 channel device, and one channel is working when the other isn't, then you can compare the side-by-side until the difference becomes apparent.

[dhmaya]

Hey Terry - how do you build an audio probe?

[Scodiddly]

Usual disclaimers about working on electronics - if you don't know what you're doing you might get electrocuted. Danger! Danger danger danger!

The first two things to do are to reseat all internal connectors and to look for obvious problems.

Reseating connectors: Ribbon connectors, whatever. Oxides build up on the surfaces, and eventually the connection no longer passed weak audio signals. If you can send in a really hot signal and the thing works for a bit afterwards then you definitely have an oxidation problem. Disconnect and reconnect anything that isn't soldered to scrape the contacts clean. Caig DeOxit is definitely a good product to use as well.

Obvious problems: Burned areas, things unplugged, etc. Use a magnifier if you need to and spend several minutes just looking at things.