The PLA is the most common cause of black screen on a C64 Computer and is located in position U17.

The GalPLA is the cheapest and the most compatible solution to be found so far.
Replaces MOS 906114-01, 82S100, 93459PC, MOS 7700/8700, 251064-01
Featuring gold plated narrow pins which won't damage your socket.
Constructed with genuine new GAL chips GAL20V8B 25ns which is the recommended choice.
All PLA's are tested and working before being shipped.
Compatible with C64 boards with Assy. 326298, 250407, 250425, 250466, 251103 (SX64)
*** Not suitable for most C64C with Assy. 250469 ***

Easy to replace if your PLA at U17 is socketed. If not then you will need to de-solder and re-socket the location.