Booting UNIX on the Plexus P/20 didn't go to plan

It's time to boot the Plexus P/20 into UNIX, or at least try to! In the previous parts I managed to dump the hard drive (for archival purposes) and dump the ROMs. In Part 2 I worked on making sure the power supplies were stable and working well enough to run the machine. Now it's time to actually try to boot this machine into UNIX and see if it works!

Part 1: https://youtu.be/iltZYXg5hZw Part 2: https://youtu.be/BPOHWBuYMGg Part 3: This part

-- Links

Plexus P/20 Discord channel at Usagi Electric: https://discord.com/invite/qNVRJnNg (Plexus channel)

General Adrian's Digital Basement channel: https://discord.com/invite/MhqUpcRj

My Github Repo (with ROM dumps and images) https://github.com/misterblack1/plexus-p20

Plexus P/20 Brochure: http://www.bitsavers.org/pdf/plexus/brochures/Plexus_P15_P20_Brochure_1985.pdf

Plexus Unix: http://www.bitsavers.org/pdf/plexus/brochures/Plexus_SYS_5.2_Brochure_1985.pdf

MFM emulator: https://www.pdp8online.com/mfm/mfm_old.shtml

Fujitsu Hard Drive Brochure: https://archive.org/details/bitsavers_fujitsubro1984_2565589

Omti 5200 Manual: https://oldcomputers.dyndns.org/public/pub/roms/omti-5400/omti_5000_series_reference_aug85.pdf

Adrian's Digital Basement Merch store: https://my-store-c82bd2-2.creator-spring.com/

Adrian's Digital Basement ][ (Second Channel) https://www.youtube.com/channel/UCbtwi4wK1YXd9AyV_4UcE6g

Support the channel on Patreon: https://www.patreon.com/adriansdigitalbasement

My GitHub repository: https://github.com/misterblack1?tab=repositories

-- 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

--- 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 ... https://www.youtube.com/watch?v=_IrxvDE6Fyo