{"id":3543,"date":"2011-09-08T08:00:56","date_gmt":"2011-09-08T12:00:56","guid":{"rendered":"http:\/\/www.engineeringradio.us\/blog\/?p=3928"},"modified":"2023-04-29T13:48:51","modified_gmt":"2023-04-29T17:48:51","slug":"things-that-make-you-go-hmmmm-part-iv","status":"publish","type":"post","link":"https:\/\/www.engineeringradio.us\/blog\/2011\/09\/things-that-make-you-go-hmmmm-part-iv\/","title":{"rendered":"Things that make you go Hmmmm? Part IV"},"content":{"rendered":"\n<p>The case of the blown fuse, or rather the blown up fuse:<\/p>\n\n\n\n<figure class=\"wp-block-image alignnone\"><a href=\"https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2011\/09\/blown-fuse.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"650\" height=\"469\" src=\"https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2011\/09\/blown-fuse.jpg\" alt=\"Blown 10 amp fuse on Harris SX5 PA board\" class=\"wp-image-3557\" srcset=\"https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2011\/09\/blown-fuse.jpg 650w, https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2011\/09\/blown-fuse-150x108.jpg 150w, https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2011\/09\/blown-fuse-300x216.jpg 300w, https:\/\/www.engineeringradio.us\/blog\/wp-content\/uploads\/2011\/09\/blown-fuse-400x288.jpg 400w\" sizes=\"auto, (max-width: 650px) 100vw, 650px\" \/><\/a><figcaption class=\"wp-element-caption\">Blown 10 amp fuse on Harris SX5 PA board<\/figcaption><\/figure>\n\n\n\n<p>F32 is blown into small bits and had to be vacuumed out of the bottom of the transmitter. \u00a0The reason why is the pair of MOSFETs connected to that circuit were shorted. \u00a0Of course, the reason for the shorting of MOSFETs needed to be investigated. \u00a0What I found was on the underside of the PA board where the brass stand-off attacked the toroid combiner board, the nuts attaching the stand-off to the combiner board were loose and there was a big arc mark.<\/p>\n\n\n\n<p>I tightened everything up and replaced the MOSFETS, marking them with a pen in case they short again, in which case the drive section needs to be closely examined.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The case of the blown fuse, or rather the blown up fuse: F32 is blown into small bits and had to be vacuumed out of the bottom of the transmitter. \u00a0The reason why is the pair of MOSFETs connected to that circuit were shorted. \u00a0Of course, the reason for the shorting of MOSFETs needed to &hellip; <a href=\"https:\/\/www.engineeringradio.us\/blog\/2011\/09\/things-that-make-you-go-hmmmm-part-iv\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Things that make you go Hmmmm? Part IV<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,21,4],"tags":[32],"class_list":["post-3543","post","type-post","status-publish","format-standard","hentry","category-general","category-tales-of-disaster","category-tech-stuff","tag-am-transmitters"],"_links":{"self":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/3543","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/comments?post=3543"}],"version-history":[{"count":5,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/3543\/revisions"}],"predecessor-version":[{"id":11726,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/3543\/revisions\/11726"}],"wp:attachment":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/media?parent=3543"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/categories?post=3543"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/tags?post=3543"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}