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diyAudio Member
Join Date: Dec 2003
Location: The Wilds Of Canada
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Kinda makes me think of all the Pioneer power amps, recievers and intergrateds. They were all designed with a regulated power supply (about 1979 and newer..last one I looked at was about 1987 or so. they were still doing it!!!!) for the preamp and pre-driver rails..that had a vertical board. OK. that's fine..BUT...they placed a resevior capacitor for that rail ABOVE the BJT/heatsunk transistor they used as a 'regulator'. The capacitor was/is almost touching the heatsink for the regulator.
Thermal runnaway and eventual failure mode of the ENTIRE amplfier was virtually assured.........capacitor drys out, reduced values in the supply, BJT goes into thermal runnaway trying to stabilize the rail voltage......poof!
They all popped off like clockwork, almost exactly at thge age of 10 years,. Every single stinking one of them. And when they went, most of the time they took most of the output circuit too. Many were deemed unrepairable.
Nice and evil job on the planned obselesence, there, Pioneer. Nice job.
The whole thing was not lost on me. No-one engineers something that way. Not that consistently, without reason. if you own -any- Pioneer gear from that year time period or newer, get in there and take a look. You may have to replace the caps to prevent the onset of this 'disease'. You have been warned. 
__________________
"Never forget that only dead fish swim with the stream." -- Malcolm Muggeridge.
"Truth cannot be brought down, rather the individual must make the effort to ascend to it." -- Jiddu Krishnamurti
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