power amp repair

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Hey all.

After searching for info and components, I have repaired the Crown D150. The oscillation is gone. It's a little noisy but swapping some caps will fix that(I hope).
Changing C7 did the trick. It wasn't C4 and the level of the input signal had nothing to do with the problem.

Thanks to all who contributed to this thread!!

However, my initial question still stands. I would like a reference book that interprets(puts a name on) waveforms.

I am presently searching for a good price for that book
"The Art of Electronics".

Thanks again,
Cracklin Audio
 
"Another reason for caution is that it's pretty easy to cause more damage, if your probe slips while you're poking around in a powered-up amplifier. I *HATE* when that happens! ;-)"

i had that happen once recently while checking the bias on a samson amp. i had just finished rebuilding a blown channel, and was checking the bias. this amp had exposed rail jumpers on top of the board passing right next to the emitter resistor leads, and one of the probes slipped, and POW!!!!



a good book to get is the "dictionary of electronics" (don't know if it's still published). i had a copy that was published for radio shack when i was young. it described just about any waveform you can think of. also any fiest year electronics textbooks should have a description of most of the basic waveforms. the basic ones you will see are:
sine, square, sawtooth, triangle, pulse train.

there are others that are combinations of those, such as clipped or rectified sine waves, or if you have an amp that is in slew rate limiting, you may see a sine wave that begins to get triangular. if you get a book on waveform analysis you will find that ALL waveforms are composed of sine waves of different frequencies combined in different amplitude and phase relationships.

you may want to get a function generator and some spectrum analyzer software. you can see the spectrum of various waveforms and how various changes in the waveform effects the balance of harmonics in the waveform
 
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