Next on the bench is an early #c64, 1982 original motherboard with 5 pin video out and a lovely ceramic VIC-II. These tend to be tricky in my experience.<\/p>\n\n\n\n Problem is it boots to a black screen. Examining the board I see signs repair attempts. Date code here is 1983, likely not original.<\/p>\n\n\n\n That kernal has to go so I removed it. Pin 9 was bent under\u2014 it was not in the via. There was an attempt.<\/p>\n\n\n\n There\u2019s actually no via anymore in some of these. The original chip was likely forcibly removed while still connected with some solder. Will need to tone these out and add bodges on the back to reconnect the damaged traces.<\/p>\n\n\n\n I\u2019ve knitted the board back together with some bodges. The #c64<\/a> still won\u2019t boot with the dead test cartridge. Remaining socketed chips (CPU, VIC-II, PLA) check out ok in another board.<\/p>\n\n\n\n September 29, 2018<\/em><\/p>\n\n\n\n Using the scope to look at some signals from this #c64. Here are the two phi clock pins on the 6510. They\u2019re supposed to be roughly the same. \u00d82 is not right.<\/p>\n\n\n\n AFAIU, \u00d82 is generated by the 6510 so I\u2019ll try swapping the CPUs with another one, even though this CPU did test ok in another board. Date codes (82 vs 84) seem to show perhaps the original owner swapped them?<\/p>\n\n\n\n From the C64 Service Manual, 6510 pin out, page 27<\/a>, lists Phi2 pin 39 as Phase 2 output. “The processor generates this clock signal from the phase 1 clock”<\/p>\n\n\n\n The \u201882 CPU in the \u201882 motherboard and it has sprung to life! My question now, were there differences in early the 6510 that matched with early #c64<\/a> motherboards?<\/p>\n\n\n\n Remember that gnarly kernal I removed? I cleaned it up so we can give it ago. Maybe it\u2019s still good?<\/p>\n\n\n\n Attached the #c64 diagnostic cart and harness and it looks great, save for SID missing voice 2 and no paddle inputs.<\/p>\n\n\n\n Thanks to 8-Bit Show And Tell<\/a> for writing this prg\u2014 I\u2019ve confirmed the VIC-II is the 64 cycle type, rather than 65 cycles like the newer.<\/p>\n\n\n\n (This was originally a Twitter thread from September 26, 2018) September 26, 2018 Next on the bench is an early #c64, 1982 original motherboard with 5 pin video out and a lovely ceramic VIC-II. These tend to be tricky in my experience.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[6,15],"tags":[42,43,52,44,51,50],"_links":{"self":[{"href":"https:\/\/biosrhythm.com\/index.php?rest_route=\/wp\/v2\/posts\/2067"}],"collection":[{"href":"https:\/\/biosrhythm.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/biosrhythm.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/biosrhythm.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/biosrhythm.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2067"}],"version-history":[{"count":3,"href":"https:\/\/biosrhythm.com\/index.php?rest_route=\/wp\/v2\/posts\/2067\/revisions"}],"predecessor-version":[{"id":2118,"href":"https:\/\/biosrhythm.com\/index.php?rest_route=\/wp\/v2\/posts\/2067\/revisions\/2118"}],"wp:attachment":[{"href":"https:\/\/biosrhythm.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2067"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/biosrhythm.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2067"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/biosrhythm.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2067"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/biosrhythm.com\/wp-content\/uploads\/2022\/11\/1045129232031129601-DoELfbyXcAIUmRM-840x630.jpg\")
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