This DRAM tester supports the following 18 and 20 pin 4 bit DRAM devices:
- 16K x 4 (e.g. TMS4416)
- 64K x 4 (e.g. TMS4464, NEC µPD41464)
- 256K x 4 (e.g. TMS44256, NEC µPD424256, etc.)
- 1024K x 4 (e.g. TC514400)
How to Use
- Connect the board to a USB port to provide power. The LED should light white.
- Put the DRAM chip in the socket with the notch at the top and pin1 the top left.
(for 18 pin parts, the bottom two socket holes should be empty) - Press the start button and wait for the result to show on the LED.
Please note that the LED will flash white/yellow while the DRAM is being tested, this is normal.
DRAM Tester for ZX Spectrum, Amiga and other retro computers and equipment.
It has a simple power requirement, needing just 5V and drawing less than 100mA, so it can be powered from any USB port with a standard micro-USB cable. The tester generates all of the required voltages (+3V3, +12V, +5V and -5V) from this single supply.
How to Use
- Connect the board to a USB port to provide power
- Put the DRAM chip in the socket with pin 1 top left.
- Press the start button and wait for the result to show on the LED.
Please note that the LED will flash White/Yellow while the DRAM is being tested, this is normal.
Results
Red | Failed Test |
Blue | Good 4416 |
Green | Good 4464 |
Magenta | Good 44256 |
Cyan | Good 514400 |
Test Times
The tester is pretty fast, based on a modern 32 bit ARM micro-controller running at 64MHz.
Here are some examples of the test times for this tester:
| Type | Size | Approximate Test Time |
| 4416 | 16Kx4 | About 6seconds |
| 4464 | 64Kx4 | About 24 seconds |
| 44256 | 256Kx4 | About 90 seconds |
| 514400 |
1Mb x 4 |
About 360 seconds |
The tests are made such that the refresh period is close to the specified maximum retention time for the part being tested.
This ensures that any issues that only occur near to the maximum retention time are also detected by this tester.
So you can be pretty sure that if a part tests as good in this tester then it should work well in a real application.
The Test Procedure
1. Measure the size of the DRAM.
2. High speed tests
- Fill the RAM with 0s and check that
- Fill the RAM with 1s and check that
- Even hash test
- Odd hash test
- Fill the RAM with random data and check that
- Repeat the above random data test several times
- Fill the RAM with random data and check that
- Repeat the above random data test several times
- Odd hash test
- Even hash test
- Fill the RAM with 1s and check that
- Fill the RAM with 0s and check that
Please note that you can also buy my 1 bit and 4 bit testers as a pack at a discount and also save on the postage here: