{"id":380,"date":"2015-02-17T21:18:15","date_gmt":"2015-02-18T02:18:15","guid":{"rendered":"http:\/\/paulcarbone.com\/blog\/?p=380"},"modified":"2017-09-24T19:36:05","modified_gmt":"2017-09-25T00:36:05","slug":"7834-readout-repairs-continued","status":"publish","type":"post","link":"https:\/\/paulcarbone.com\/blog\/7834-readout-repairs-continued\/","title":{"rendered":"7834 Readout repairs, continued"},"content":{"rendered":"<p>&nbsp;<\/p>\n<p>After my <a title=\"Tektronix 7834 Mainframe readout repairs\" href=\"http:\/\/paulcarbone.com\/blog\/?p=240\">previous antics<\/a> with the 7834 readout system, the outcome was:<\/p>\n<ul>\n<li>U3401 Zeros logic &amp; memory \u2013 tek part 155-0018 &#8211; the original culprit.\u00a0 Replaced with one from ebay.<\/li>\n<li>U3418 Column decoder \u2013\u00a0 tek part 155-0014, which I think I killed during repairs. Replaced with one from ebay.<\/li>\n<li>U3477 7402 quad 2 input NOR gate \u2013 smoked during repairs.\u00a0 Replaced with a 74ALS02 from stock.<\/li>\n<li>It turned out U3232, the row data switch that cycles through the 8 plugin display channels was bad as well,\u00a0 botching the readout in horizontal A bottom, and horizontal B top &amp; bottom.\u00a0\u00a0 Replacement sourced from ebay.<\/li>\n<\/ul>\n<p>So far, I&#8217;ve spent $50 on the scope, and another $50 or so on replacement chips.\u00a0 Still not bad at all.<\/p>\n<p>Here&#8217;s a few shots using the 7B85&#8217;s delta time feature, which lets you do fun things like measure frequency, rise-time, and pulse-width directly using the on-screen delay time read-out.\u00a0 Thanks to Peter on the TekWiki <a title=\"7B85 tek wiki entry\" href=\"http:\/\/proxy.w140.com\/tekwiki\/wiki\/7B85\" target=\"_blank\">who&#8217;s entry on the 7B85<\/a> pointed out these features.<\/p>\n<p>These photos are of a rudimentary clock circuit I made using parts from the DF01<\/p>\n<p><img loading=\"lazy\" class=\"alignnone size-full wp-image-381\" src=\"https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender.jpg\" alt=\"FullSizeRender\" width=\"3264\" height=\"2448\" srcset=\"https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender.jpg 3264w, https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender-300x225.jpg 300w, https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender-1024x768.jpg 1024w, https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender-400x300.jpg 400w\" sizes=\"(max-width: 3264px) 100vw, 3264px\" \/> <a href=\"http:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender-1.jpg\"><img loading=\"lazy\" class=\"alignnone size-full wp-image-382\" src=\"https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender-1.jpg\" alt=\"FullSizeRender-1\" width=\"3264\" height=\"2448\" srcset=\"https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender-1.jpg 3264w, https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender-1-300x225.jpg 300w, https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender-1-1024x768.jpg 1024w, https:\/\/paulcarbone.com\/blog\/wp-content\/uploads\/2015\/02\/FullSizeRender-1-400x300.jpg 400w\" sizes=\"(max-width: 3264px) 100vw, 3264px\" \/><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>&nbsp; After my previous antics with the 7834 readout system, the outcome was: U3401 Zeros logic &amp; memory \u2013 tek part 155-0018 &#8211; the original culprit.\u00a0 Replaced with one from ebay. U3418 Column decoder \u2013\u00a0 tek part 155-0014, which I &hellip; <a href=\"https:\/\/paulcarbone.com\/blog\/7834-readout-repairs-continued\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[26],"tags":[63],"table_tags":[],"_links":{"self":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/380"}],"collection":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/comments?post=380"}],"version-history":[{"count":2,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/380\/revisions"}],"predecessor-version":[{"id":391,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/posts\/380\/revisions\/391"}],"wp:attachment":[{"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/media?parent=380"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/categories?post=380"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/tags?post=380"},{"taxonomy":"table_tags","embeddable":true,"href":"https:\/\/paulcarbone.com\/blog\/wp-json\/wp\/v2\/table_tags?post=380"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}