Can you replace your C64 PLA for under $3?

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Adrian's Digital Basement

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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):

PIN headers:

24 pin narrow sockets:

--- Tools

Deoxit D5:

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)

Heat Sinks:

Little squeezy bottles: (available elsewhere too)

--- Links

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:

--- Music

Intro music by:
Nathan Divino

Outro Music:
Abyss by | e s c p |
Music promoted by
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

--- Donate

To donate to the basement:
Adrian Black / Mail Call PMB 244
4110 SE Hawthorne Blvd.
Portland, OR 97214-5246
United States