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.

0:00 - GAL-PLA Overview
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) **
http://www.freepascal.org/~daniel/c64...

The "PLAin" Truth About the Commodore 64 PLA (and why MOS PLA chips fail so often)
   • #10 'The PLAin Truth About the Commod...  

More information on the PLA including timing requirements:
ftp://ftp.zimmers.net/pub/cbm/c64/firmware/C64_PLA_Dissected.pdf

Super Zaxxon Cart provided by Geek With Social Skills:
   / geekwithsocialskills  

--- Parts for this project

PCBWay to the GAL-PLA project:
https://www.pcbway.com/project/sharep...

TL866-II Mini Pro Programmer:
https://www.aliexpress.com/item/40000...

Lattice GAL20V8 (Qty 10):
https://www.aliexpress.com/item/33023...

PIN headers:
https://www.aliexpress.com/item/32692...

24 pin narrow sockets:
https://www.aliexpress.com/item/32950...

--- Tools

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

Jonard Tools EX-2 Chip Extractor:
https://amzn.to/2VazxDS
https://www.jonard.com/Products/EX-2-...

Wiha Chip Lifter:
https://amzn.to/3a9ftWw
https://www.wihatools.com/precision-c...

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/

--- C64 Stuff

JaffyDOS:
http://blog.worldofjani.com/?p=3544

C64 Test Harness I use:
   • Building a Commodore 64 Diagnostic Te...  

C64 Homebrew cartridge PCB: (used for the DeadTest / Diag Cart I use)
https://www.ebay.com/itm/Commodore-64...

EasyFlash 3 Multi-Cart:
http://store.go4retro.com/easyflash-3/

--- Instructional videos

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

--- Music

Intro music by:
Nathan Divino
@itsnathandivino

Outro Music:
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)
https://creativecommons.org/licenses/...

--- Image Credits

TI99 Image Credit:
By Rama & Musée Bolo - Own work, CC BY-SA 2.0 fr
https://commons.wikimedia.org/w/index...