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Audio and Video Talk
The Vintage Audio Section
My trusty Quad 405 MK 1 is fixed!
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<blockquote data-quote="mafioso" data-source="post: 825029" data-attributes="member: 572"><p>Hi PeterC</p><p></p><p>I have a couple of multimeters including Fluke and I also have a good 2-channel Isotech 35MHz oscilloscope.</p><p></p><p>These tools I use for mc cartridge making and my diagnostic knowledge of amplifiers are just about zero. I can make old amps look new again and can repair or replace faulty bits if I can physically SEE the problem. Amp theory and repair is not in my limited knowledge of electronics.</p><p></p><p>The friend helping me is a retired Telkom test equipment technician and repairer and he has an abundance of very expensive Fluke test gear coasting many thousands of $$.</p><p></p><p>It is interesting you mentioned HF oscillation. My friend also mentioned the same possibility which we will check out after the holidays.</p><p></p><p>All I will do before he returns to the job, will be to switch on the amp and let it play for 5 mins or so and then switch off and unplug and then 'feel' the board to determine thje area which cvaued the massive overheating a few days ago after I let it play for +-25 minutes. If it is HF oscillation, this excercise will probably be futile as I'm guessing all components on the board will be equally hot.</p><p></p><p>Thank you for your advice & a very Merry Christmas and the same for 2018 and beyond.</p><p></p><p>skollie</p></blockquote><p></p>
[QUOTE="mafioso, post: 825029, member: 572"] Hi PeterC I have a couple of multimeters including Fluke and I also have a good 2-channel Isotech 35MHz oscilloscope. These tools I use for mc cartridge making and my diagnostic knowledge of amplifiers are just about zero. I can make old amps look new again and can repair or replace faulty bits if I can physically SEE the problem. Amp theory and repair is not in my limited knowledge of electronics. The friend helping me is a retired Telkom test equipment technician and repairer and he has an abundance of very expensive Fluke test gear coasting many thousands of $$. It is interesting you mentioned HF oscillation. My friend also mentioned the same possibility which we will check out after the holidays. All I will do before he returns to the job, will be to switch on the amp and let it play for 5 mins or so and then switch off and unplug and then 'feel' the board to determine thje area which cvaued the massive overheating a few days ago after I let it play for +-25 minutes. If it is HF oscillation, this excercise will probably be futile as I'm guessing all components on the board will be equally hot. Thank you for your advice & a very Merry Christmas and the same for 2018 and beyond. skollie [/QUOTE]
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Audio and Video Talk
The Vintage Audio Section
My trusty Quad 405 MK 1 is fixed!
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