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Audio and Video Talk
The Vintage Audio Section
Any amp geniuses here willing to give advice?
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<blockquote data-quote="Rick" data-source="post: 847281" data-attributes="member: 17143"><p>Thanks both for valuable advice much appreciated, noted, I will play detective now, and feed back with any success or discovery.</p><p></p><p>The amount of failed components I have already replaced, especially diodes in this thing defy belief, but have not done a few that measured "OK".</p><p></p><p>Cap story very possible, also I have seen transistors that pass the diode test but the gain curve is totally messed up. This amp is a beautifully built classic to me, but I am surprised at how many components in it were shot, then again I do not know its history and 1979 was a while ago (Just short of 40 years old it is). It does remind me of working on the two Marantz PM94 repeatedly exploding-for-nothing but everything measures ok with something that never fails has failed amps with separate boards all over the place.</p><p></p><p>There's a lesson in this for me to just go buy a variac now and stop avoiding. To those that know there is nothing worse than that sub one second loud transformer hum, a click and then smoke - flying at the off button anyway even though its too late and you know that short sound and strange smell is at least another R240 again, it adds up fast.</p></blockquote><p></p>
[QUOTE="Rick, post: 847281, member: 17143"] Thanks both for valuable advice much appreciated, noted, I will play detective now, and feed back with any success or discovery. The amount of failed components I have already replaced, especially diodes in this thing defy belief, but have not done a few that measured "OK". Cap story very possible, also I have seen transistors that pass the diode test but the gain curve is totally messed up. This amp is a beautifully built classic to me, but I am surprised at how many components in it were shot, then again I do not know its history and 1979 was a while ago (Just short of 40 years old it is). It does remind me of working on the two Marantz PM94 repeatedly exploding-for-nothing but everything measures ok with something that never fails has failed amps with separate boards all over the place. There's a lesson in this for me to just go buy a variac now and stop avoiding. To those that know there is nothing worse than that sub one second loud transformer hum, a click and then smoke - flying at the off button anyway even though its too late and you know that short sound and strange smell is at least another R240 again, it adds up fast. [/QUOTE]
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Audio and Video Talk
The Vintage Audio Section
Any amp geniuses here willing to give advice?
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