07-12-2016, 06:32 PM
I'm a member of HiFi Engine and have already downloaded the service manual, studying the circuit. AS for current limited PSUs, I agree that they are very useful, but I only have two, one goes up to +22v @ 2A max, the other up to ca. +18v @ 10A Max. The latter is an ex car radio demo stand PSU, the former I built many years ago to a design published in PW. Since I mainly work on portables & car radios, these are adequate for those jobs, though I have succesfully repaired quite a few HiFi amps. over the last 10 years or so without the problems I'm having with the HK1400. As to what is termed 'blanket replacement', I'm sure I read somewhere, maybe on this forum or on UKVRRR that, because, as I well know, an o/p stage failure can damage transistors upstream of the output, so replacement of all Transistors in the defective channel is the way to go. I'm sure someone said that, in his days as a service engineer, this was less time consuming than any other way to proceed.
