The DramArduino Is a "Two Hour, Two Dollar" Arduino Uno Shield for Testing Vintage DRAM Chips
Maker Jan Beta has put together a simple tester for dynamic RAM (DRAM) chips, based around an Arduino Uno or compatible microcontroller and "leftover components I found in my parts bin" — using a design released under a "do with them what you want" license.
Described as a "two hour, two dollar" project, Beta's take on the DramArduino is designed for checking the functionality of 4164 and 41256 DRAM chips of the types commonly found in vintage computers. "Testing is not too fast but acceptable — four different passes are performed in about 80 seconds total," pseudonymous project creator "iss" explains. "Results are 100 percent reliable only if the test FAILS - you can throw away the chip without fear."
Designed as a shield add-on for use with an Arduino Uno or pin-compatible microcontroller board, the device was originally designed and built on prototyping boards in order to check a bulk batch of chips for bad ones before attempting to use any of them in a vintage Tangerine Oric-1 home computer from the 1980s.
"Working with the tool is easy: place the chip in the ZIF socket, press small reset button, wait until GREEN LED blinks," iss writes. "If it remains permanently on - chip is OK, if the chip is bad - RED LED lights. If USB is connected, status is reported in your serial console. This helped me to detect some 'lazy' chips - they failed in different [ways], on every next test, growing addresses but when they become 'hot' test passes always."
A video showing Beta's take on the tester is available on YouTube. The original creator, iss, released the source code and schematics for the project on the Defence Force Oric forum, under a "do with them what you want" open-source license.