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/c64pla/
The "PLAin" Truth About the Commodore 64 PLA (and why MOS PLA chips fail so often)
https://youtu.be/ofg33zk9uCA?t=346
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:
https://www.youtube.com/user/geekwithsocialskills
--- Parts for this project
PCBWay to the GAL-PLA project:
https://www.pcbway.com/project/shareproject/Commodore_64_PLA_replacement.html
TL866-II Mini Pro Programmer:
https://www.aliexpress.com/item/4000052064914.html
Lattice GAL20V8 (Qty 10):
https://www.aliexpress.com/item/33023102444.html
PIN headers:
https://www.aliexpress.com/item/32692992041.html
24 pin narrow sockets:
https://www.aliexpress.com/item/32950113625.html
--- Tools
Deoxit D5:
https://amzn.to/2VvOKy1
http://store.caig.com/s.nl/it.A/id.1602/.f
Jonard Tools EX-2 Chip Extractor:
https://amzn.to/2VazxDS
https://www.jonard.com/Products/EX-2-DIP-IC-Extractor-24-40-Pins
Wiha Chip Lifter:
https://amzn.to/3a9ftWw
https://www.wihatools.com/precision-chip-lifter
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/digital-oscilloscopes/1000z/
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/33000308958.html
TS100 Soldering Iron:
https://amzn.to/2K36dJ5
https://www.ebay.com/itm/TS100-65W-MINI-Digital-OLED-Programmable-Soldering-Iron-Anti-static-Structure/113382669853
EEVBlog 121GW Multimeter:
https://www.eevblog.com/product/121gw/
DSLogic Basic Logic Analyzer:
https://amzn.to/2RDSDQw
https://www.ebay.com/itm/USB-Logic-DSLogic-Basic-Analyzer-16Ch-100MHz-4Ch-400MHz-Xilinx-Spartan-6-FPGA/202543965672
Magnetic Screw Holder:
https://amzn.to/3b8LOhG
https://www.harborfreight.com/4-inch-magnetic-parts-tray-90566.html
Universal ZIP sockets: (clones, used on my ZIF-64 test machine)
https://www.ebay.com/itm/14-16-18-20-24-28-32-40-pin-IC-Test-Universal-ZIF-Socket-Fs/303206721971
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-Micro-Scissor-125mm-PLATO-170-Electronics-Cutter-Side-Cutting-Pliers/163458746184
Heat Sinks:
https://www.aliexpress.com/item/32537183709.html
Little squeezy bottles: (available elsewhere too)
https://amzn.to/3b8LOOI
--- Links
My GitHub repository:
https://github.com/misterblack1?tab=repositories
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:
https://youtu.be/szSzA6T4Kdw
C64 Homebrew cartridge PCB: (used for the DeadTest / Diag Cart I use)
https://www.ebay.com/itm/Commodore-64-C64-C128-NEW-bare-HomeBrew-DEVelopment-cartridge-board-8-32k-2019/162430154398
EasyFlash 3 Multi-Cart:
http://store.go4retro.com/easyflash-3/
--- Instructional videos
My video on damage-free chip removal:
https://www.youtube.com/watch?v=XQVjwPsVFd8
--- 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/by/4.0/
--- Image Credits
TI99 Image Credit:
By Rama & Musée Bolo - Own work, CC BY-SA 2.0 fr
https://commons.wikimedia.org/w/index.php?curid=36785342