{"id":1542,"date":"2019-11-04T13:59:52","date_gmt":"2019-11-04T13:59:52","guid":{"rendered":"http:\/\/www.randomorbit.co.uk\/?p=1542"},"modified":"2019-11-04T13:59:53","modified_gmt":"2019-11-04T13:59:53","slug":"consolidated-computer-inc-pdp-8-clone-part-7-the-memory-boards","status":"publish","type":"post","link":"https:\/\/www.randomorbit.co.uk\/?p=1542","title":{"rendered":"Consolidated Computer Inc. PDP-8 Clone \u2013 Part 7. the memory boards."},"content":{"rendered":"\n<p class=\"has-drop-cap wp-block-paragraph\">Having taken a look at and a brush to, the first few boards, I have come to the memory boards. This machine has 32kwords of 13 bit core memory in two memory modules.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">There is a memory bus controller board but I didn&#8217;t take a photo of that. I did get photos of the memory modules themselves though.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"alignleft\"><a href=\"http:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191102_144851803.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"225\" height=\"300\" src=\"http:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191102_144851803-225x300.jpg\" alt=\"\" class=\"wp-image-1526\" srcset=\"https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191102_144851803-225x300.jpg 225w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191102_144851803-768x1024.jpg 768w\" sizes=\"auto, (max-width: 225px) 100vw, 225px\" \/><\/a><figcaption>Top view of the 16kw x 13 bit core memory module.<\/figcaption><\/figure><\/div>\n\n\n\n<p class=\"wp-block-paragraph\" style=\"text-align:left\">The memory modules were made by <strong>Ampex<\/strong> and have a customer part number containing the initials <strong>CCI<\/strong>. This must mean the boards were made specifically for CCI and were not off-the-shelf-items just bought in. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Looking from either side of the module it is not overly obvious that there is any core memory at all. It&#8217;s well protected between the two PCBs that make up the module.<\/p>\n\n\n\n<div class=\"wp-block-coblocks-gallery-stacked alignright\"><ul class=\"coblocks-gallery has-fullwidth-images\"><li class=\"coblocks-gallery--item\"><figure class=\"coblocks-gallery--figure\"><a href=\"http:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191102_144904470-1024x768.jpg\" rel=\"\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"http:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191102_144904470-1024x768.jpg\" alt=\"\" data-id=\"1527\" data-imglink=\"\" data-link=\"http:\/\/www.randomorbit.co.uk\/?attachment_id=1527\" class=\"wp-image-1527 has-shadow-none\" srcset=\"https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191102_144904470-1024x768.jpg 1024w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191102_144904470-300x225.jpg 300w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191102_144904470-768x576.jpg 768w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><figcaption class=\"coblocks-gallery--caption\">Bottom view of the 16kw x 13 bit core memory module.<\/figcaption><\/figure><\/li><\/ul><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Identical in every way?<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">When I was cleaning the first of the modules I noticed a broken resistor. I struggled to read the value bands so I took a look at the other module, one I hadn&#8217;t cleaned at all, and it had the same broken resistor!<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"alignleft\"><a href=\"http:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_121524180-crop.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"300\" src=\"http:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_121524180-crop-300x300.jpg\" alt=\"\" class=\"wp-image-1541\" srcset=\"https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_121524180-crop-300x300.jpg 300w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_121524180-crop-150x150.jpg 150w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_121524180-crop-768x767.jpg 768w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_121524180-crop-1024x1024.jpg 1024w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_121524180-crop-45x45.jpg 45w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_121524180-crop.jpg 1385w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption>Two view of the upper memory board showing the broken resistor<\/figcaption><\/figure><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">I had a word on the VCFED forums and the view of the team was that the resistors were 510 Ohms. A quick raid of the parts bags and two new resistors were fitted.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"225\" src=\"http:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_140133702-crop-300x225.jpg\" alt=\"\" class=\"wp-image-1538\" srcset=\"https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_140133702-crop-300x225.jpg 300w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_140133702-crop-768x576.jpg 768w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_140133702-crop-1024x768.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><figcaption>Top view of the upper memory board showing the replacement resistor.<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Having to part the two boards that make up each memory module gave me the opportunity to take a look at the core memory itself.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The core array is behind a steel plate and a sticker warning me that I was about the void the warranty.<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"alignleft\"><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"225\" src=\"http:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_143412906-300x225.jpg\" alt=\"\" class=\"wp-image-1539\" srcset=\"https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_143412906-300x225.jpg 300w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_143412906-768x576.jpg 768w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_143412906-1024x768.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><figcaption>View of the core memory array.<\/figcaption><\/figure><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">I was very careful when removing the metal plate and I&#8217;m glad that I was. This is the smallest core I have see I think. Sadly I don&#8217;t have a standard banana for scale but trust me, the cores are tiny.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"225\" src=\"http:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_143432371-300x225.jpg\" alt=\"\" class=\"wp-image-1540\" srcset=\"https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_143432371-300x225.jpg 300w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_143432371-768x576.jpg 768w, https:\/\/www.randomorbit.co.uk\/wordpress\/wp-content\/uploads\/2019\/11\/IMG_20191103_143432371-1024x768.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><figcaption>Close up of the core memory array.<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Having taken a look at and a brush to, the first few boards, I have come to the memory boards. This machine has 32kwords of 13 bit core memory in two memory modules. There is a memory bus controller board but I didn&#8217;t take a photo of that. I did get photos of the memory &hellip; <a href=\"https:\/\/www.randomorbit.co.uk\/?p=1542\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Consolidated Computer Inc. PDP-8 Clone \u2013 Part 7. the memory boards.<\/span> <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":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","footnotes":""},"categories":[47,135,136,33],"tags":[140,143,138,141],"class_list":["post-1542","post","type-post","status-publish","format-standard","hentry","category-c93-blog-posts","category-cci-pdp-8-clone","category-retro-computing","category-c84-retro-tech","tag-computers","tag-dec","tag-pdp-8","tag-retro"],"featured_image_src":null,"author_info":{"display_name":"andy","author_link":"https:\/\/www.randomorbit.co.uk\/?author=1"},"_links":{"self":[{"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/1542","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1542"}],"version-history":[{"count":3,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/1542\/revisions"}],"predecessor-version":[{"id":1545,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=\/wp\/v2\/posts\/1542\/revisions\/1545"}],"wp:attachment":[{"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1542"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1542"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.randomorbit.co.uk\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1542"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}