Shared March 14, 2020
Bad PLA chips (MOS 906114-01) are a super common problem for the "breadbin" Commodore 64 machines. There are replacements around but they aren't that cheap. How about one you can build yourself at home for under $3?
The GAL-PLA has been tested on longboard PCB 326298, 250407, 250425 and the SX64 with no compatibility issues or modifications required. Tested with Super Zaxxon, 1541 Ultimate II and Easy Flash 3 with no issues on both NTSC and PAL machines.
10:57 - Testing the GAL-PLA with Super Zaxxon
13:45 - How to build your own PLA
25:43 - Cost breakdown of the GAL-PLA replacement
--- Video Links
*** GAL-PLA Website by Daniël Mantione: (All of the information and files to build your own) ***
The "PLAin" Truth About the Commodore 64 PLA (and why MOS PLA chips fail so often)
More information on the PLA including timing requirements:
Super Zaxxon Cart provided by Geek With Social Skills:
--- Parts for this project
PCBWay to the GAL-PLA project:
TL866-II Mini Pro Programmer:
Lattice GAL20V8 (Qty 10):
24 pin narrow sockets:
Jonard Tools EX-2 Chip Extractor:
Wiha Chip Lifter:
Elenco Electronics LP-560 Logic Probe:
Hakko FR301 Desoldering Iron:
Rigol DS1054Z Four Channel Oscilloscope:
Head Worn Magnifying Goggles / Dual Lens Flip-In Head Magnifier:
TL866II Plus Chip Tester and EPROM programmer: (The MiniPro)
TS100 Soldering Iron:
EEVBlog 121GW Multimeter:
DSLogic Basic Logic Analyzer:
Magnetic Screw Holder: (also on eBay and Amazon)
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
RetroTink 2X Upconverter: (to hook up something like a C64 to HDMI)
Plato (Clone) Side Cutters: (order five)
Little squeezy bottles: (available elsewhere too)
My GitHub repository:
Commodore Computer Club / Vancouver, WA – Portland, OR – PDX Commodore Users Group
--- C64 Stuff
C64 Test Harness I use:
C64 Homebrew cartridge PCB: (used for the DeadTest / Diag Cart I use)
EasyFlash 3 Multi-Cart:
--- Instructional videos
My video on damage-free chip removal:
Intro music by:
Abyss by | e s c p | https://escp-music.bandcamp.com
Music promoted by https://www.free-stock-music.com
Attribution 4.0 International (CC BY 4.0)
--- Image Credits
TI99 Image Credit:
By Rama & Musée Bolo - Own work, CC BY-SA 2.0 fr
To donate to the basement:
Adrian Black / Mail Call PMB 244
4110 SE Hawthorne Blvd.
Portland, OR 97214-5246
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