First power up of the Plexus P/20 dual processor UNIX system

In our second installment of the Plexus P/20 series, it's time to try to power-up this old machine and see if we can get it to show some signs of life. Machines like this can be complex, so without any documentation or information about it, I'll have to do a lot of figuring things out as I go.

Part 1:    • What is this rare multi-user UNIX wor...  
Part 2: This part!
Part 3:    • Booting UNIX on the Plexus P/20 didn'...  
Part 4:    • We made some unbelievable discoveries...  

-- Links

Discord channel: (where we are discussing this machine and other stuff)
  / discord  

My Github Repo (with ROM dumps, technical information and images)
https://github.com/misterblack1/plexu...

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

Plexus Unix:
http://www.bitsavers.org/pdf/plexus/b...

MFM emulator:
https://www.pdp8online.com/mfm/mfm_ol...

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

Omti 5200 Manual:
https://oldcomputers.dyndns.org/publi...

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

Adrian's Digital Basement ][ (Second Channel)
   / @adriansdigitalbasement2  

Support the channel on Patreon:
  / adriansdigitalbasement  

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

-- Tools

Deoxit D5:
https://amzn.to/2VvOKy1
http://store.caig.com/s.nl/it.A/id.16...

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/digi...

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/33000...

TS100 Soldering Iron:
https://amzn.to/2K36dJ5
https://www.ebay.com/itm/TS100-65W-MI...

EEVBlog 121GW Multimeter:
https://www.eevblog.com/product/121gw/

DSLogic Basic Logic Analyzer:
https://amzn.to/2RDSDQw
https://www.ebay.com/itm/USB-Logic-DS...

Magnetic Screw Holder:
https://amzn.to/3b8LOhG
https://www.harborfreight.com/4-inch-...

Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
https://www.ebay.com/itm/14-16-18-20-...

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-...

Heat Sinks:
https://www.aliexpress.com/item/32537...

Little squeezy bottles: (available elsewhere too)
https://amzn.to/3b8LOOI

--- Instructional videos

My video on damage-free chip removal:
   • How to remove chips without damaging ...  

--- Music

Intro music and other tracks by:
Nathan Divino
@itsnathandivino