Retrobrighting worked well ... until it didn't (Atari ST 520)

It's time to finally get this almost-trashed Atari ST booting off the external floppy drive. Also, it's time to try to improve the cosmetic look of this very yellowed machine. Will this result in a disaster? Part 1: https://www.youtube.com/watch?v=c7nBu5za3yA Part 2: https://www.youtube.com/watch?v=uV-ytWuGMS0 Part 3: This part! Part 4: https://youtu.be/uqWCmKcaZtI --- Video Links Display Turntable I use for retrobrighting: https://amzn.to/3zXIIZw Indoor retrobrite process using blue light: https://www.youtube.com/watch?v=cRlAFnhmPlw https://www.youtube.com/watch?v=-vNWZXKEvWs Using a heat gun to fix sun damaged plastic: https://www.youtube.com/watch?v=dQo58oqpows Adrian's Digital Basement ][ (Second Channel) https://www.youtube.com/channel/UCbtwi4wK1YXd9AyV_4UcE6g Support the channel on Patreon: https://www.patreon.com/adriansdigitalbasement -- Tools Deoxit D5: https://amzn.to/2VvOKy1 http://store.caig.com/s.nl/it.A/id.1602/.f O-Ring Pick Set: (I use these to lift chips off boards) https://amzn.to/3a9x54J Elenco Electronics LP-560 Logic Probe: https://amzn.to/2VrT5lW Hakko FR301 Desoldering Iron: https://amzn.to/2ye6xC0 Rigol DS1054Z Four Channel Oscilloscope: https://www.rigolna.com/products/digital-oscilloscopes/1000z/ Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier: https://amzn.to/3adRbuy TL866II Plus Chip Tester and EPROM programmer: (The MiniPro) https://amzn.to/2wG4tlP https://www.aliexpress.com/item/33000308958.html TS100 Soldering Iron: https://amzn.to/2K36dJ5 https://www.ebay.com/itm/TS100-65W-MINI-Digital-OLED-Programmable-Soldering-Iron-Anti-static-Structure/113382669853 EEVBlog 121GW Multimeter: https://www.eevblog.com/product/121gw/ DSLogic Basic Logic Analyzer: https://amzn.to/2RDSDQw https://www.ebay.com/itm/USB-Logic-DSLogic-Basic-Analyzer-16Ch-100MHz-4Ch-400MHz-Xilinx-Spartan-6-FPGA/202543965672 Magnetic Screw Holder: https://amzn.to/3b8LOhG https://www.harborfreight.com/4-inch-magnetic-parts-tray-90566.html Universal ZIP sockets: (clones, used on my ZIF-64 test machine) https://www.ebay.com/itm/14-16-18-20-24-28-32-40-pin-IC-Test-Universal-ZIF-Socket-Fs/303206721971 RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI) http://www.retrotink.com/ Plato (Clone) Side Cutters: (order five) https://www.ebay.com/itm/1-2-5-10PCS-Micro-Scissor-125mm-PLATO-170-Electronics-Cutter-Side-Cutting-Pliers/163458746184 Heat Sinks: https://www.aliexpress.com/item/32537183709.html Little squeezy bottles: (available elsewhere too) https://amzn.to/3b8LOOI --- Links My GitHub repository: https://github.com/misterblack1?tab=repositories Commodore Computer Club / Vancouver, WA – Portland, OR – PDX Commodore Users Group https://www.commodorecomputerclub.com/ --- Instructional videos My video on damage-free chip removal: https://www.youtube.com/watch?v=XQVjwPsVFd8 --- Music Intro music and other tracks by: Nathan Divino @itsnathandivino