{"id":9226,"date":"2020-05-29T17:29:08","date_gmt":"2020-05-29T17:29:08","guid":{"rendered":"https:\/\/stevepedwards.today\/stevepedwards.com\/ElectronicsStuff\/?p=9226"},"modified":"2020-05-29T17:29:08","modified_gmt":"2020-05-29T17:29:08","slug":"technics-su-v1x-intermittent-noise","status":"publish","type":"post","link":"https:\/\/stevepedwards.today\/ElectronicsStuff\/technics-su-v1x-intermittent-noise\/","title":{"rendered":"Technics SU-V1X &#8211; Intermittent Noise"},"content":{"rendered":"<p>Lots of egg frying going on with nasty spikes - worse on the left than right channel - and not solved by the change of filter caps to new EBay fake Nichicon 4700uF - that aren't even 4100uF...I'll leave them in as the original caps are 25 years old but test fine.<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-large wp-image-9390\" src=\"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-content\/uploads\/2020\/05\/IMG_20200529_175345506-1024x576.jpg\" alt=\"\" width=\"840\" height=\"473\" \/><br \/>\nSeems more like driver transistors and as most components have black leg rot, then probably noisy transistors somewhere. Not helped by the equally noisy balance pot either...<br \/>\nThe obvious transistors to change are q420-21 I guess?<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-9394\" src=\"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-content\/uploads\/2020\/05\/q401-2.png\" alt=\"\" width=\"643\" height=\"485\" \/><br \/>\nAnd maybe the 50V, 3.3uF electrolytics to C401-2 in the audio chain of the Voltage amp IC401.<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-9400\" src=\"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-content\/uploads\/2020\/05\/C401.png\" alt=\"\" width=\"250\" height=\"398\" \/><br \/>\nAll I can do is go with my gut feeling that this is a cap breaking down at power on and remove one at a time for a recap. I have no other logic to guide me here as I can't even split the audio chain in half by removing one, as a collapsing DC rail could cause these noises, as well as noisy components (which I think there are too).<br \/>\n<iframe loading=\"lazy\" title=\"SU V1X mains noise on power on\" width=\"1778\" height=\"1000\" src=\"https:\/\/www.youtube.com\/embed\/u5qEwfQJsqA?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><br \/>\n..and of course...these mains noises also blew my lovely Minimus 26s! Arse!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Lots of egg frying going on with nasty spikes - worse on the left than right channel - and not solved by the change of filter caps to new EBay fake Nichicon 4700uF - that aren't even 4100uF...I'll leave them in as the original caps are 25 years old but test fine. Seems more like <a href=\"https:\/\/stevepedwards.today\/ElectronicsStuff\/technics-su-v1x-intermittent-noise\/\" class=\"more-link\">...<span class=\"screen-reader-text\">  Technics SU-V1X &#8211; Intermittent Noise<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-9226","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-json\/wp\/v2\/posts\/9226","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-json\/wp\/v2\/comments?post=9226"}],"version-history":[{"count":0,"href":"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-json\/wp\/v2\/posts\/9226\/revisions"}],"wp:attachment":[{"href":"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-json\/wp\/v2\/media?parent=9226"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-json\/wp\/v2\/categories?post=9226"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stevepedwards.today\/ElectronicsStuff\/wp-json\/wp\/v2\/tags?post=9226"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}