{"id":44,"date":"2022-06-22T14:02:49","date_gmt":"2022-06-22T14:02:49","guid":{"rendered":"https:\/\/maddox.pro\/?p=44"},"modified":"2022-06-22T14:02:49","modified_gmt":"2022-06-22T14:02:49","slug":"fairlight-an-interesting-discovery","status":"publish","type":"post","link":"https:\/\/www.maddox.pro\/?p=44","title":{"rendered":"Fairlight, an interesting discovery"},"content":{"rendered":"\n

So I decided to check a few of the PCBs, now this is a IIx so it should have voice cards with CEM3320 filters on, but no matter where I look I cannot find them.<\/p>\n\n\n\n

\"\"
Fairlight CMI voice board (CMI-01)<\/figcaption><\/figure>\n\n\n\n

After a bit of digging, it seems the owner says it was a I, then upgraded to a II and then a IIx, but it looks like they kept the voice cards from the I. This uses a switched capacitor style VCF (top left using a 4066 and a 4136 quad op-amp). <\/p>\n\n\n\n

A friend shared a picture of his Fairlight II voice board and the CEM3320 is on the bottom left (you can see the four red capacitors around it) and it has a lot more trimmers than this one, 7 Vs the 1!<\/p>\n\n\n\n

\"\"
And a Fairlight II board (CMI-01-A)<\/figcaption><\/figure>\n\n\n\n

I’ve been busy reading the service guide that I have and I feel that I’m happy enough with the power supply to now start working on it (with all the boards removed). <\/p>\n\n\n\n

First will be to isolate as many supplies as I can from the main transformer and check the capacitors (they are big and many) <\/p>\n\n\n\n

Next power it up with these disconnected and confirm if it blows a fuse or not. Currently it doesn’t blow a fuse immediately (with the regular circuits but now load) it takes maybe 2 or 3 seconds. Which makes me think that its unlikely to be the mains transformer. <\/p>\n","protected":false},"excerpt":{"rendered":"

So I decided to check a few of the PCBs, now this is a IIx so it should have voice cards with CEM3320 filters on, but no matter where I look I cannot find them. After a bit of digging, it seems the owner says it was a I, then upgraded to a II and then a IIx, but it looks like they kept the voice cards from the I. This uses a switched capacitor style VCF (top left using a 4066 and a 4136 quad op-amp). A friend shared a picture of his Fairlight II voice board and the CEM3320 is on the bottom left (you can see the four red capacitors around it) and it has a lot more trimmers than this one, 7 Vs the 1! I’ve been busy reading the service guide that I have and I feel that I’m happy enough with the power supply to now start working on it (with all the boards removed). First will be to isolate as many supplies as I can from the main transformer and check the capacitors (they are big and many) Next power it up with these disconnected and confirm if it blows a fuse or not. Currently it doesn’t blow a fuse immediately (with the regular circuits but now load) it takes maybe 2 or 3 seconds. Which makes me think that its unlikely to be the mains transformer.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[7,6],"tags":[],"class_list":["post-44","post","type-post","status-publish","format-standard","hentry","category-fairlight","category-repairs"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.maddox.pro\/index.php?rest_route=\/wp\/v2\/posts\/44","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.maddox.pro\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.maddox.pro\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.maddox.pro\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.maddox.pro\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=44"}],"version-history":[{"count":1,"href":"https:\/\/www.maddox.pro\/index.php?rest_route=\/wp\/v2\/posts\/44\/revisions"}],"predecessor-version":[{"id":47,"href":"https:\/\/www.maddox.pro\/index.php?rest_route=\/wp\/v2\/posts\/44\/revisions\/47"}],"wp:attachment":[{"href":"https:\/\/www.maddox.pro\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=44"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.maddox.pro\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=44"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.maddox.pro\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=44"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}