{"id":9229,"date":"2016-10-29T10:42:18","date_gmt":"2016-10-29T14:42:18","guid":{"rendered":"http:\/\/www.engineeringradio.us\/blog\/?p=9229"},"modified":"2023-03-19T11:53:03","modified_gmt":"2023-03-19T15:53:03","slug":"the-energy-onix-pulsar-transmitter","status":"publish","type":"post","link":"https:\/\/www.engineeringradio.us\/blog\/2016\/10\/the-energy-onix-pulsar-transmitter\/","title":{"rendered":"The Energy Onix Pulsar transmitter"},"content":{"rendered":"

Engineering Radio: The Oh Dear God Edition.<\/p>\n

I have been tasked with fixing one of these glorious contraptions. Aside from the usual Energy Onix quirks; design changes not reflected in the schematic diagram and a company that no longer exists, it seems to fairly simple machine. Unfortunately, it has spent its life in less-than-ideal operating conditions.<\/p>\n

\"Energy<\/a>
Energy Onix Pulsar 1000 in the wild. Excuse the potato-quality photo<\/figcaption><\/figure>\n

Upon arrival, it was dead in the water.\u00a0 Found copious mouse droppings, dirt, and other detritus within and without the transmitter.\u00a0 Repaired the broken start\/stop switches, fixed the RF drive detector, replaced the power supply capacitors, and now at least the unit runs.\u00a0 The problem now is the power control is unstable.\u00a0 The unit comes up at full power when it is first switched on, then it drops back to 40 watts, then after it warms up more goes to about 400 watts and the audio sounds distorted.\u00a0 This all points towards some type of thermal issue with one of the power control op-amps or another composite device.<\/p>\n

After studying the not-always-accurate schematic diagrams, the source of the problem seems to be the carrier-level control circuit.\u00a0 This is based around a Fairchild RC4200AN (U10 on the Audio\/PDM driver board) which is an analog multiplier chip.\u00a0\u00a0 That chip sets the level of the PDM audio output which is fed into the PDM integrator circuit.\u00a0 Of course, that chip is no longer manufactured.\u00a0 I can order one from China on eBay and perhaps that will work out okay.\u00a0 This all brings to mind the life cycle of solid-state components.\u00a0 One problem with the new technology; most solid-state components have a short production life, especially things like multiplier chips.\u00a0 Transmitters are generally expected to last 15-20 years in primary service.\u00a0 Thus, transmitter manufacturers need to use chips that will not become obsolete (good luck with that), or purchase and maintain a large stock of spare parts.<\/p>\n

In the meantime, the chip is on its way from China.\u00a0 Truth be told, this fellow would be better off with a new transmitter.<\/p>\n","protected":false},"excerpt":{"rendered":"

Engineering Radio: The Oh Dear God Edition. I have been tasked with fixing one of these glorious contraptions. Aside from the usual Energy Onix quirks; design changes not reflected in the schematic diagram and a company that no longer exists, it seems to fairly simple machine. Unfortunately, it has spent its life in less-than-ideal operating … Continue reading The Energy Onix Pulsar transmitter<\/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":[4],"tags":[87,245],"class_list":["post-9229","post","type-post","status-publish","format-standard","hentry","category-tech-stuff","tag-am","tag-am-transmitter"],"_links":{"self":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/9229","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=9229"}],"version-history":[{"count":6,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/9229\/revisions"}],"predecessor-version":[{"id":11111,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/posts\/9229\/revisions\/11111"}],"wp:attachment":[{"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/media?parent=9229"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/categories?post=9229"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.engineeringradio.us\/blog\/wp-json\/wp\/v2\/tags?post=9229"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}