Mystery ATARI 8-bit from eBay Restoration and Upgrade

In this episode I finish a half upgraded ATARI I bought on eBay which is not what it says on the badge. It needs some cleaning and restoration as the keys are yellowed and the case is marbled from a previous restoration attempt. Apologies for my voice being all over the place, I am still recovering from a cold and my vocal cords are still not okay. Here are the promised links for the upgrades in the Atari YOOMP! https://yoomp.atari.pl/ [you can buy a physical copy, but digital version (download) is free] Ultimate 1MB board: https://lotharek.pl/productdetail.php... TK-II-Stereo https://ataribits.weebly.com/installa... AMP hookup schema https://ataribits.weebly.com/uploads/... SIO2SD (biggus dickus version) https://lotharek.pl/productdetail.php... 00:00 - Intro 00:19 - Task description 01:30 - Disassembly 02:47 - The surprise 03:34 - The plan 04:28 - Keyboard disassembly 06:26 - Cleaning and Retr0brite 07:58 - Fixing the upgrade 10:01 - Test 1 10:38 - Reassembling the keyboard 12:00 - Case modification 12:24 - Final assembly 13:00 - Test 2 13:50 - Yoomp! 14:15 - Conclusion 14:37 - SIO2SD box 15:52 - I Love 8bit computers 16:08 - Outro