Using our new diagnostic ROM to fix a TRS-80 Model III!

#trs-80 #repair

The TRS-80 Model III is fixed! As you saw in part 1, I was really stumped by the problems this board had -- so I reached out to friends Frank and David about making a diagnostic ROM for this machine. I posted a companion video on the second channel taking a deeper dive to the ROM, I recommend you watch that after watching this video. The repair showed off how even someone as "seasoned" as me can make fundamental mistakes in the troubleshooting process.... So watch to find out what mistakes I made, and what it took to get this machine running again!

Thanks for Frank IZ8DWF and David KI3V for making the diagnostic ROM a reality.

Part 1:    • TRS-80 Model III garbage at boot repair  
Part 2: This part!

Diagnostic ROM deep dive companion video:
   • Let's talk: Our brand new TRS-80 Diagnosti...  

--- Video Links

TRS-80 Model 3 (and Model 1) diagnostic ROM:
https://github.com/misterblack1/trs80...

2364 adapter PCB:
https://www.pcbway.com/project/sharep...

Frank IZ8DWF's channel: (for really amazing repairs)
   / iz8dwf  

When good caps go bad: (t-shirt donated by Jesse)
https://www.teepublic.com/t-shirt/241...

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  

-- 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

--- Links

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

Commodore Computer Club / Vancouver, WA – Portland, OR – PDX Commodore Users Group
https://www.commodorecomputerclub.com/

--- Instructional videos

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

--- Music

Intro music and other tracks by:
Nathan Divino
@itsnathandivino