I'd like to improve my electronics skills....any suggestions??

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Hey everyone -

I've been crazy about hifi since I was a kid and love to repair/restore/rebuild, but I'm getting increasingly frustrated at my lack of skills: I would love to learn more, particularly about diagnosing and fault-tracing. Right now I have a room full of stuff I love and would never part with, but it's useless because I can't diagnose the faults and will never be able to afford to hire someone else to repair it. Anyway, where's the fun in someone else doing it??:confused:

I'm not a complete know-nothing: I'm fine with all mechanical things (turntables, cassette transports). In addition, I solder REALLY nicely (I was taught by a pro) and know the very basics of electronics....I can spot a leaking capacitor, I know what resistors/caps/transistors do, and I can use a multimeter. That sort of stuff. And I know enough not to blow myself up or get zapped.

So can anyone recommend good websites, books, or anything? All the books I get are either too basic and I don't learn anything, or too advanced and I feel like Homer Simpson. Any advice would be appreciated!!

Thanks:D
Bruce
 
Pre amps and power supplies are quite straight forward to fix.

Power amplifiers with feedback are not so easy. A fault anywhere in the loop will feed around the whole circuit.

However you can look for things like shorted output transistors. Blown fuses are usually because of power supply fault or output transistors.

I have seen me give up on some power amp faults and simply remove all the semiconductors to test them out of circuit. While they are out I check all the passive components.
A Hfe check of all transistors is a good check as I once had a transistor with an Hfe of 1.

I had a horrible fault once where I bought an amplifier as not working. I removed all the components and they were all ok and so were the passives. Turned out in the end someone had put in a npn transistor instead of a pnp !
 
Thanks Nigel - I just repaired a bunch of dry joints on an amp board in my Deon dual-mono power amp....now one side is overheating. If I knew more I'd be able to fix it, it's so frustrating!!:mad: However I know enough to check the DC offset and go from there.

Anyway, the point is that you're encouraging me to learn more and go out there and do it!

B:)
 
If you want to fix any audio circuit, first u have to locate the faulty stage. In general, what it means is a stage between two signal coupling components which keeps the dc bias separated from the consecutive stages on both sides.

Any big circuit is a combination of small circuits and you have to learn about the small ones.

Edit: Having a dual mono amp, the good channel should be used for comparison.

Gajanan Phadte
 
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Ahh...you want to learn.

Read lots of data sheets in the test or applications sections...figure out what each part is doing and why it has the value it does.

opamps-regulators-BJT-Mosfets

linear regulators-SMPS

amplifiers: Class A, AB, D, etc

Look at the requirements of each part.

The more familiar you are with that then the better your troubleshooting skills will be.

IMHO

:)
 
The Radio Amateurs Handbook (ARRL) and the Radio Communications Handbook (RSGB) are often available secondhand, it's not necessary to get the most recent one, they always have a good section which is an introduction to electronics and they take a sensible, no-nonsense approach to getting it across to people who may not have an academic knowledge.

I know they're not directly aimed at audio, but there are sections dealing with audio as any radio has an audio section. I used to read them as a child, I can't recommend them highly enough. The material ranges from simple to the most complex electronics imaginable in the more recent editions, but is backed up with a great deal of practical experience.

The Art of Electronics by Paul Horowitz and Winfield Hill is widely regarded as one of the best practical books on all aspects of electronics, and likewise contains a lot of practical information. It's frequently recommended here.

One of my favourite compendiums of advanced knowledge (theory) is Digital and Analog Communication Systems by Leon W. Couch II. This has stuff on noise, encoding, modulation schemes, serious stuff that is necessary if you need to design modems, or mobile phones, or satellite TV, but invaluable as a reference.

Theodore Bogart has done some good books on the basic physics, magnetic and electric circuits, which eventually become necessary if you want to understand a bit about the design of transformers and which leads eventually into an understanding of Maxwell's equations.

A book on digital signal processing is probably required to round things out a bit. These are often a bit impenetrable though, you could try Ifeachor & Jervis, Digital Signal Processing: a Practical Approach.

That's probably enough to be going on with.
 
If I may humbly add a small recommendation: you must certainly read the good stuff already recommended here, but you also learn a lot by *doing*.

Just try and do. Make sure you're in safety with electricity and injuries, but then just try.
I learn a lot by just spending tons of time "trying", whatever it is that you feel like trying at a given point. Sometimes going hardheadedly the wrong way, and that consumes a lot of time, and often it just doesn't work and you throw away the thing. But when it works, then you really like it!!
And you know which chapter to read next in the books.

Also building something from scratch is very didactical. A basic power supply, a simple headphone amp, and on and on. That too gives you a path and a "target" through the theory.

I wish we were neighbours...



_
 
We need soldering reached a deep level, to be achieved the degree of BGA, it would take some time to practice.And electronic products are becoming more integrated, I've operated the machine for BGA about two years,but some mainboards of laptop are still difficult to be soldered.
 
There are some good videoes on youtube about soldering through hole and SMD.

I had some trouble with SMPS soic8 ic. I kept blowing it up soldering it in.
In the end I found I needed a temperature controlled iron just warm enough to melt the solder and some liquid flux to help things flow a bit better.

I found it just about impossible to remove ic's with an iron so bought a hot air gun.
 
Consider NOT working on stuff you care about.

In fact it might make sense to buy a known junker amp, tube or solid state, and repairing or rebuilding it into something else.

I second "The Art of Electronics" by Horowitz and Hill, the writing is very very easy to follow. Probably the best written electronics book in history.

If you do tubes then you want a copy of the 4th edition of Radiotron Designer's Handbook. It's available as a download pdf too, on Pete Millet's great site (along with a ton of other classic reference books).

So, the way to do this is to work on something that you can afford to have fry and blow up... you NEED a 'scope, a DVM, and a signal generator (or other suitable source of sine and squarwaves). The scope's calibrator signal will be ok for square wave. You can buy a $30 DSS module on epay that does all sorts of frequencies and other tricks now. A bright light over the bench... the 'scope is essential. No scope? Can't really work on audio gear.

_-_-
 
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