[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-560025-105":59,"doc-detail-560025-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","no-operation-power-supply-troubleshooting","No Operation - Power supply troubleshooting","","Power supply faults can manifest as “No Operation” when the supply to the primary control IC (IC702) drops below 5V, making start-up behavior unreliable. The document outlines targeted checks: measure with the meter ground connected to the negative end of the smoothing block, inspect R770 and R771 for low supply voltage to IC702, and note common failures at R721 and R703 that can cause a low 5V rail. It also covers IC707 (secondary 5V regulator) failure causing no turn-on despite power-up, and explains that low HT (30–40V) issues may result from R713/R714 increasing in value or breaking down under load, emphasizing substitution testing.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":20,"@type":76,"position":81},"https://docshare.wps.com/document/exam/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/no-operation-power-supply-troubleshooting/560025/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/no-operation-power-supply-troubleshooting/560025.png","ImageObject",300,407,{"name":92,"@type":93},"Connor ","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","text/plain","2026-11-09","2026-10-12",true,{"@type":102,"interactionType":103,"userInteractionCount":24},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"What typically causes the “No Operation” symptom related to IC702?","Question",{"text":112,"@type":113},"If the supply on pin one of IC702 falls below 5V, the power supply operation becomes unreliable and the set may not function correctly.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"Which components should be checked for low supply voltage to IC702?",{"text":117,"@type":113},"Check R770 (270Ω safety) and R771 (470kΩ) for low supply voltage to IC702, and also consider R721 and R703 (both 150kΩ) failing and causing a low 5V line.",{"name":119,"@type":110,"acceptedAnswer":120},"How can low HT (about 30–40V) be caused and what is the recommended test?",{"text":121,"@type":113},"Low HT can occur if R713 and R714 go high or break down under load. They should be checked by substitution because they may read OK on a meter even when faulty, and they should be metal film resistors rather than carbon composition.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},560025,1791801875,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":19,"category_name":20,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":24,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":8,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":129,"read_time":81,"preview_page_count":4},687207022233,"https://ap-avatar.wpscdn.com/davatar_155a257f0dc6eb9ab79c44ca47cae57d","No Operation\nNo operation can be caused by a number of components, the most common being around the primary control IC, IC702. \nIf the supply on pin one of this IC falls below 5V, the operation of the power supply becomes unreliable. (Note: that you will have to connect your meter ground to the negative end of the smoothing block.) \nAs can be seen from the previous circuit description, the supply circuit is fairly complex, however only a few components cause problems. For\nlow supply voltage to IC702 check R770 (270? safety) and R771  (470k?). It has also been known for R721 and R703 (both 150k?) to fail causing a low 5V line.\nIC707 (the secondary 5V regulator) can fail leading to a set that does not turn on, even though the power supply starts\nup. Normally its output goes low at around 3V.\nNo operation of the power supply or low HT (at about 30 to 40V) can be caused by R713 and R714 going high or\nbreaking down under load. It is important that these two resistors are checked by substitution as they often read OK on\na meter, even though they are faulty. Note that they should be metal film resistors and not carbon composition.","cbCairOv4qutU79L","https://ap.wps.com/l/cbCairOv4qutU79L","txt",1150,"English","# No Operation\n## Primary control IC supply check (IC702)\n## Secondary 5V regulator failure (IC707)\n## Low HT causes and resistor substitution (R713/R714)","[{\"question\":\"What typically causes the “No Operation” symptom related to IC702?\",\"answer\":\"If the supply on pin one of IC702 falls below 5V, the power supply operation becomes unreliable and the set may not function correctly.\"},{\"question\":\"Which components should be checked for low supply voltage to IC702?\",\"answer\":\"Check R770 (270Ω safety) and R771 (470kΩ) for low supply voltage to IC702, and also consider R721 and R703 (both 150kΩ) failing and causing a low 5V line.\"},{\"question\":\"How can low HT (about 30–40V) be caused and what is the recommended test?\",\"answer\":\"Low HT can occur if R713 and R714 go high or break down under load. They should be checked by substitution because they may read OK on a meter even when faulty, and they should be metal film resistors rather than carbon composition.\"}]","No Operation - Power supply troubleshooting | TXT"]