{"id":1453,"date":"2020-12-21T17:50:18","date_gmt":"2020-12-21T07:50:18","guid":{"rendered":"https:\/\/blog.hegars.com\/?p=1453"},"modified":"2020-12-23T21:55:10","modified_gmt":"2020-12-23T11:55:10","slug":"486-build-biostar-mb-1420-25-33pb-pv","status":"publish","type":"post","link":"https:\/\/blog.hegars.com\/?p=1453","title":{"rendered":"BioStar MB-1420\/25\/33PB\/PV Repair"},"content":{"rendered":"\n<p>I found a 486 board circa 1991 on ebay that was having keyboard issues so I grabbed it not knowing much more than that, When I received it, it seemed to be in really good condition otherwise. It&#8217;s a Biostar MB-1420\/25\/33PB\/PV<\/p>\n\n\n\n<figure class=\"wp-block-image size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image.png\" alt=\"\" class=\"wp-image-1455\" width=\"777\" height=\"751\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image.png 777w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-300x290.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-768x742.png 768w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-480x464.png 480w\" sizes=\"(max-width: 777px) 100vw, 777px\" \/><\/figure>\n\n\n\n<p>This is a no frills 486 board, no cache no nothing., it has a 66MHz clock tho so its got that going for it.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"650\" height=\"575\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-4.png\" alt=\"\" class=\"wp-image-1470\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-4.png 650w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-4-300x265.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-4-480x425.png 480w\" sizes=\"(max-width: 650px) 100vw, 650px\" \/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"583\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-14-1024x583.png\" alt=\"\" class=\"wp-image-1508\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-14-1024x583.png 1024w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-14-300x171.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-14-768x438.png 768w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-14-1080x615.png 1080w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-14-1280x729.png 1280w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-14-980x558.png 980w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-14-480x273.png 480w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-14.png 1320w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Inbuilt CPU<\/h3>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"984\" height=\"1000\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-13.png\" alt=\"\" class=\"wp-image-1492\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-13.png 984w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-13-295x300.png 295w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-13-768x780.png 768w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-13-980x996.png 980w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-13-480x488.png 480w\" sizes=\"(max-width: 984px) 100vw, 984px\" \/><\/figure>\n\n\n\n<p><a href=\"https:\/\/www.cpu-world.com\/CPUs\/80486\/Intel-KU80486SX-25.html\">https:\/\/www.cpu-world.com\/CPUs\/80486\/Intel-KU80486SX-25.html<\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The Issue<\/h2>\n\n\n\n<p>As expected it was the good old leaky NiCAD trick which ate out the two keyboard CLK and DATA traces, (also had a good crack at the &#8220;Power Good&#8221; signal but it seems to be fine, for now)<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"460\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-5-1024x460.png\" alt=\"\" class=\"wp-image-1472\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-5-1024x460.png 1024w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-5-300x135.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-5-768x345.png 768w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-5-1080x485.png 1080w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-5-980x441.png 980w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-5-480x216.png 480w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-5.png 1228w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">The Repair<\/h2>\n\n\n\n<p>Trace back <\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/www.vogons.org\/download\/file.php?id=30504&amp;mode=view\" alt=\"\"\/><\/figure>\n\n\n\n<p>Hiding under the keyboard controller is the 7407<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"754\" height=\"229\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-9.png\" alt=\"\" class=\"wp-image-1478\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-9.png 754w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-9-300x91.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-9-480x146.png 480w\" sizes=\"(max-width: 754px) 100vw, 754px\" \/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"750\" height=\"207\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-8.png\" alt=\"\" class=\"wp-image-1477\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-8.png 750w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-8-300x83.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-8-480x132.png 480w\" sizes=\"(max-width: 750px) 100vw, 750px\" \/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"443\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-6-1024x443.png\" alt=\"\" class=\"wp-image-1474\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-6-1024x443.png 1024w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-6-300x130.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-6-768x332.png 768w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-6-1080x467.png 1080w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-6-980x424.png 980w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-6-480x208.png 480w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-6.png 1226w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption>using 30AWG  hooked one back to the board trace then the other sat in the PTH<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"608\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-7-1024x608.png\" alt=\"\" class=\"wp-image-1475\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-7-1024x608.png 1024w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-7-300x178.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-7-768x456.png 768w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-7-1080x641.png 1080w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-7-1280x760.png 1280w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-7-980x582.png 980w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-7-480x285.png 480w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-7.png 1383w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption>the DIN connector just sat over the top of the wires without issue<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">BIOS<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"749\" height=\"325\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-1.png\" alt=\"\" class=\"wp-image-1457\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-1.png 749w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-1-300x130.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-1-480x208.png 480w\" sizes=\"(max-width: 749px) 100vw, 749px\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">BOIS Dump<\/h3>\n\n\n\n<div class=\"wp-block-file\"><a href=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/MB-1433PB.7z\">MB-1433PB.BIN<\/a><a href=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/MB-1433PB.7z\" class=\"wp-block-file__button\" download>Download<\/a><\/div>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"622\" height=\"371\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-2.png\" alt=\"\" class=\"wp-image-1463\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-2.png 622w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-2-300x179.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-2-480x286.png 480w\" sizes=\"(max-width: 622px) 100vw, 622px\" \/><figcaption>Texas Instrument TMS27C512<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">First Boot<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Port 0x80<\/h3>\n\n\n\n<p>This boards chipset doesn&#8217;t have port 0x80 support so the standard diag cards didn&#8217;t help here<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Booting<\/h3>\n\n\n\n<p>was still getting 8 beeps, turns out the ram was imbalanced,<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"771\" height=\"477\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-10.png\" alt=\"\" class=\"wp-image-1481\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-10.png 771w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-10-300x186.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-10-768x475.png 768w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-10-480x297.png 480w\" sizes=\"(max-width: 771px) 100vw, 771px\" \/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"705\" height=\"1024\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-11-705x1024.png\" alt=\"\" class=\"wp-image-1482\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-11-705x1024.png 705w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-11-207x300.png 207w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-11-480x697.png 480w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-11.png 725w\" sizes=\"(max-width: 705px) 100vw, 705px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Configuration<\/h2>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/pcrebuilding.altervista.org\/images\/resized_my_pcrebuilding\/th99_20\/32447-1.png\" alt=\"\"\/><\/figure>\n\n\n\n<div class=\"wp-block-file\"><a href=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/jumper_settings.txt\">jumper_settings<\/a><a href=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/jumper_settings.txt\" class=\"wp-block-file__button\" download>Download<\/a><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Going Forward<\/h2>\n\n\n\n<p>Overdrive Time!<\/p>\n\n\n\n<p>The one I have is a DX2OPDR66, the 168pin &#8220;ODPR&#8221; version but this board has a empty 169th pin for the &#8220;ODP&#8221; version of the upgrade&#8230; shrug,,,<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"351\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-15-1024x351.png\" alt=\"\" class=\"wp-image-1515\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-15-1024x351.png 1024w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-15-300x103.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-15-768x263.png 768w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-15-1536x526.png 1536w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-15-1080x370.png 1080w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-15-1280x438.png 1280w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-15-980x336.png 980w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-15-480x164.png 480w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-15.png 1629w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p><a href=\"https:\/\/www.cpu-world.com\/CPUs\/80486u\/Intel-DX2ODPR66.html\">https:\/\/www.cpu-world.com\/CPUs\/80486u\/Intel-DX2ODPR66.html<\/a><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"817\" height=\"815\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-12.png\" alt=\"\" class=\"wp-image-1485\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-12.png 817w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-12-300x300.png 300w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-12-150x150.png 150w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-12-768x766.png 768w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-12-480x479.png 480w\" sizes=\"(max-width: 817px) 100vw, 817px\" \/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"306\" height=\"631\" src=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-3.png\" alt=\"\" class=\"wp-image-1468\" srcset=\"https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-3.png 306w, https:\/\/blog.hegars.com\/wp-content\/uploads\/2020\/12\/image-3-145x300.png 145w\" sizes=\"(max-width: 306px) 100vw, 306px\" \/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>I found a 486 board circa 1991 on ebay that was having keyboard issues so I grabbed it not knowing much more than that, When I received it, it seemed to be in really good condition otherwise. It&#8217;s a Biostar MB-1420\/25\/33PB\/PV This is a no frills 486 board, no cache no nothing., it has a [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-container-style":"default","site-container-layout":"default","site-sidebar-layout":"default","disable-article-header":"default","disable-site-header":"default","disable-site-footer":"default","disable-content-area-spacing":"default","footnotes":""},"categories":[18,33],"tags":[],"_links":{"self":[{"href":"https:\/\/blog.hegars.com\/index.php?rest_route=\/wp\/v2\/posts\/1453"}],"collection":[{"href":"https:\/\/blog.hegars.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.hegars.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.hegars.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.hegars.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1453"}],"version-history":[{"count":40,"href":"https:\/\/blog.hegars.com\/index.php?rest_route=\/wp\/v2\/posts\/1453\/revisions"}],"predecessor-version":[{"id":1516,"href":"https:\/\/blog.hegars.com\/index.php?rest_route=\/wp\/v2\/posts\/1453\/revisions\/1516"}],"wp:attachment":[{"href":"https:\/\/blog.hegars.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1453"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.hegars.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1453"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.hegars.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1453"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}