4164 / 41256 Dynamic RAM Tester
Arduino based DRAM tester for 4164 and 41256 memory chips. These chips are commonly used in retro computers and arcade machines from the 80’s
The PCB features short circuit protection in the form of a resettable fuse and also has 100 ohm resistors in series with each address/data line to protect against damaged chips under test (Shorts to GND or Vcc)
4164 and 41256 memory chips can be tested by selecting the appropriate jumper.
Each memory address is checked multiple times for any errors.
Green LED indicates DRAM is working.
Red LED indicates DRAM is faulty.
Instructions:
- Insert 4164 / 41256 into ZIF socket (Make sure pin 1 is closest to lever. Pin1 marked on PCB)
- Select jumper for testing 4164 or 41256
- Connect mini USB cable.
Testing will start. First the poly fuse is checked. If the fuse is blown the red LED will pulse in 1s intervals. (If this happens then the chip under test is faulty and is drawing too much current which has caused the fuse to blow. The polyfuse will reset after it’s cooled down after a few minutes.)
- Flashing green indicates test in progress
- Red LED means the RAM fails testing and is faulty.
- Green LED means RAM passed. (4164 test takes approx 40 seconds, 41256 test takes approx 2 mins)
Make sure the orientation of the chip is correct. Failure do to so and you risk destroying the chip
If you connect an Arduino IDE or serial program to the USB port it will output the address of the memory location that fails the test. (Baud 115200)
The tester does not come with a USB Cable. You will need a micro USB type B cable.
The colour of the PCB may be different from the picture (Red, green or blue)
