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Krell amplifier repair

Started by jpcar, October 27, 2020, 08:35:18 PM

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joecool85

Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

Overthruster

Quote from: jpcar on October 27, 2020, 08:35:18 PM
I'm trying to trace through the power amp section of a Krell hifi amp.

Cute bit of trivia: The Krell company was named after the alien race in the classic 1956 sci-fi movie Forbidden Planet (starring Leslie Nielsen!) Supposedly the founder was taken with the line "The fool, the meddling idiot! As though his ape's brain could contain the secrets of the Krell!"

JoshR77

Quote from: jpcar on October 27, 2020, 08:35:18 PM
Hi,

I'm trying to trace through the power amp section of a Krell hifi amp. The right channel is working fine but the left is outputting a very low signal - about 10% of the good channel.
Schematic is attached.
I fed a 500Hz sine 80mVpp into the input with a signal generator. All voltages I've marked are peak to peak.
On the good channel, before R171 reads 80mV and then after is 2V. On the bad channel this point only gains to 120mV.
Can anyone offer advice as to where I should be looking next?

Thanks!

Great job!