{"id":9120,"date":"2019-11-06T10:05:49","date_gmt":"2019-11-06T15:05:49","guid":{"rendered":"http:\/\/www.willegal.net\/blog\/?p=9120"},"modified":"2019-11-06T10:05:49","modified_gmt":"2019-11-06T15:05:49","slug":"i-started-testing-the-digital-group-video-card","status":"publish","type":"post","link":"http:\/\/www.willegal.net\/blog\/?p=9120","title":{"rendered":"I Started Testing the Digital Group Video Card"},"content":{"rendered":"\n

So far, I’ve tested power rails and they appear to be reasonably good. The SCELBI power supplies provide +5 and -9. In addition, components on this card need -5 and +12. The -5 is generated on board using a series of voltage dropping diodes connected to the -9 supply. The +12 is generated with the little converter that can be seen mounted on top of the board. That converter has been documented in a few previous posts. The -5 supply sits at something like 5.6, which is a bit on the high side, but I’ll just go with it. The +12 looks pretty good, as it is sitting at 11.8. Voltages could change a little bit in actual operation as the testing was done without a running clock. I’ll definitely keep an eye on that as I move forward with more testing.<\/p>\n\n\n\n

\"Reproduction
Reproduction DG Video Card<\/figcaption><\/figure>\n\n\n\n

I am expecting the crystal that I need to arrive next week. The installed crystal is something I had on hand in a parts bin. It is something like 3.6 Mhz, which I figured is close enough that I could use it to check clock generation and general performance of the timing portions of the circuit.<\/p>\n","protected":false},"excerpt":{"rendered":"

So far, I’ve tested power rails and they appear to be reasonably good. The SCELBI power supplies provide +5 and -9. In addition, components on this card need -5 and +12. The -5 is generated on board using a series … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16,7],"tags":[],"class_list":["post-9120","post","type-post","status-publish","format-standard","hentry","category-8008-scelbi","category-apple"],"_links":{"self":[{"href":"http:\/\/www.willegal.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/9120","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.willegal.net\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.willegal.net\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.willegal.net\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.willegal.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9120"}],"version-history":[{"count":1,"href":"http:\/\/www.willegal.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/9120\/revisions"}],"predecessor-version":[{"id":9121,"href":"http:\/\/www.willegal.net\/blog\/index.php?rest_route=\/wp\/v2\/posts\/9120\/revisions\/9121"}],"wp:attachment":[{"href":"http:\/\/www.willegal.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9120"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.willegal.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9120"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.willegal.net\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}