I've bought A600 4MB Fast RAM expansion with pre-programmed CPLD and without LED. I've obtained the RAM chips from local auction portal. Soldered everything and put to my A600. Initially I've got orange screen, but I soon revealed that the expansion is not well fitting the CPU. I carefully observed the photos in the offer to determine that top socket edges and bottom limiter must be trimmed and in addition extra trim is required for the resistor near the CPU - this is the only hack this kit requires. I've trimmed the socket in few minutes, installed again, and it works! Great! Thank you for that kit!
The item arrived two days after shipping. All parts work well and are consistent with the github page about this design. It works very good (very low response time) and will save my C64 if need be (and save my mental health in doing so). Thank you for making it easy for everyone. I will recommend your designs to others.
Response from SukkoPera's Retro Works | June 24, 2019
Thanks for your review, Ronald. I'll add those chips to the compatibility list. I'm sorry the socket did not work your you, actually I find those are pretty good and grip to the CPU very tightly, provided that you don't plug/unplug them too many times. Did you file it a bit so that it doesn't get in the way of R102?
You can do this "Drive Switcher" yourself by using two (or three) stacked 40pin IC sockets and make the proper switching by wires on pin 13/14 and a 2-way, 6-pin switch. This is like "manual" switching.
This board offers a "chip" to do the switching, with either a jumper or a simple on/off switch (3 pin). It makes things interesting as you can, with proper circuitry, do the switching by reset (timer).
I like the board but the chip that came with the board was busted and it could be, probably, my fault! I used a better brand (DM74LS157N) to replace the existing one and everything went fine.