5101 SRAM Tester
These chips are commonly used in retro computers & arcade machines from the 80’s.
Features:
- 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)
- 5 different types of memory checks are perfomed, and this is looped through 10 times.
- Status messages and any errors, including addresses that fail, are written out to the serial port. You can use an Arduino IDE Serial Monitor (Or any other serial program) set to 115200 baud to view these messages.
- When testing the red and green LED’s alternate indicating that data is being written and read from the chip.
Due to the 5101 chip being wider than a normal DIP chip it has a tight fit into the ZIF socket. The legs might need to be bend outwards in order to fit
(See photos for closeup of the chip in the ZIF socket)
Chips with short or trimmed legs might not make proper contact with the ZIF socket.
There are speed limitations on the Arduino so while the memory checks are thorough it cannot test the 5101 chip as it’s maximum possible speed. It is therefore possible that even though the 5101 passes all memory tests it could fail at higher clock speeds (Though this is unlikely from my testing)
Instructions:
- Insert the 5101 chip into the ZIF socket (Make sure pin 1 is closest to lever. Pin1 marked on PCB)
- Connect micro USB cable. (Not supplied)
- Testing will start. First the poly fuse checked. If the fuse is blown the red LED will pulse in 0.5s 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 red/green indicates test in progress (Data R/W to the chip)
- Red LED means the RAM fails testing and is faulty.
- Green LED means RAM passed. (Test takes approx 70 seconds)
Make sure the orientation of the 5101 is correct. Failure do to so and you risk destroying the chip
