This DRAM tester supports 1 bit DRAM devices from 4Kbit to 1Mbit (eg. MCM4096, M4027P,4116, TMS4532NL3/4, M3723L/H, 4164, 4128, 41256, MCM511000 etc. ). Support for 4Kbit parts (e.g. M4027 & MCM4096).
33.98$
DRAM Tester for ZX Spectrum, C64, Oric, Jupiter Ace and other retro computers and equipment.
This DRAM tester supports 1 bit DRAM devices from 4Kbit to 1Mbit (eg. MCM4096, M4027P, 4116, TMS4532NL3/4, M3723L/H, 4164, 4128, 41256, MCM511000 etc.).
Features of this tester not found in other DRAM testers:
- Support for 4Kbit parts (e.g. M4027 & MCM4096)
- Support for 32Kbit parts (e.g. TMS4532 & M3732)
- Support for piggybacked DRAM such as Samsung KM4128 used in early PCs
- Multicolour LED output to make the results simpler to read and more intuitive (e.g. working columns show as a horizontal bar, working rows as a vertical bar, fully working as a a square box)
As far as I know, this is the only tester available that will test the parts above, but this is essential if you want to keep the replacement parts in your retro computer kit the same as the original.
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 correct socket: The left socket is for parts that require -5V on pin 1, +12V on pin8, +5V on pin 9 and 0V on pin 16 (e.g. MCM4096, M4027P, 4108 and 4116), all other types should ONLY be tested in the right socket.
- Press the start button and wait for the result to show on the LEDs.
Please note that the LEDs will flicker while the DRAM is being tested, this is normal.
Example 16 Pin Parts That Need -5V(pin 1), +12V(pin 8) & +5V(pin 9) (LEFT SOCKET)
Example 16 Pin Parts That Use a Single +5V Supply (MIDDLE SOCKET)
Please do not put any of these parts in the left-hand socket. Testing any of these in there could damage the part and/or the tester
Example Results
LED Off | No Block |
LED Red | Bad Block |
LED Blue | Good 4Kbit Block |
LED Green | Good 16Kbit Block |
LED Magenta | Good 64Kbit Block |
LED Cyan | Good 256Kbit Block |
| Part | Size | Socket | Pass |
| Mostek MK4027P or Motorola MCM4096 | 4 Kbit | Left |
|
| Mostek MK4108-x0 or TI TMS4108-x0 | 4 Kbit | Left |
|
| Mostek MK4108-x1 or TI TMS4108-x1 | 4 Kbit | Left |
|
| ITT/STC 4116 | 16 Kbit | Left |
|
| Mostek MK4116 | 16 Kbit | Left |
|
| Mostek MK4516 | 16 Kbit | Middle |
|
| Hitachi HM4816 | 16 Kbit | Middle |
|
| Intel 2118 | 16 Kbit | Middle |
|
| TI TMS4532xL3 | 32 Kbit | Middle |
|
| TI TMS4532xL4 | 32 Kbit | Middle |
|
| OKI M3732L | 32 Kbit | Middle |
|
| OKI M3732H | 32 Kbit | Middle |
|
| Hitachi HM4864 | 64 Kbit | Middle |
|
| Micron MT4264 | 64 Kbit | Middle |
|
| 4164 | 64 Kbit | Middle |
|
| 4128 | 128 Kbit | Middle |
|
| 4256 or 41256 | 256 Kbit | Middle |
|
| MCM511000 or HM511000 | 1024 Kbit | Right |
|
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 |
| 4027/4096 | 4Kb | About 2 seconds |
| 4116 | 16Kb | About 5 seconds |
| 4164 | 64Kb | About 20 seconds |
| 4128 | 128Kb | About 42 seconds |
| 41256 | 256Kb | About 82 seconds |
| 511000 | 1024Kb | About 330 seconds |
The tests are made such that the refresh period is close to the specified maximum retention time for the part being tested.
That means close to 4ms for 64 rows on an M4027 or MCM4096, 2ms for 128 rows on a 4116 part and close to 4ms for the 256 rows on a 4164 or 41256 part.
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
If you have access to a 3D printer and would like to print a case for this tester then please contact me and I will send you the STL files for 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:
| Brand | Unbranded |
| Type | Memory |
| Manufacturer warranty | 1 year |
| Country/Region of Manufacture | United Kingdom |
| Vintage | Yes |
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