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Vintage DRAM & SRAM Tester for 16 different RAM Types
Fast, open-source DRAM/SRAM tester for retro computers – C64, C128, Amiga, Atari, ZX Spectrum, BBC Micro, Apple IIe and many more. Built around an ATmega328P, tests memory thoroughly in seconds.
Over 200 units sold worldwide. As featured on:
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Adrian's Digital Basement (May 2026): Mail Call #5 – 25 min hands-on: "This is freaking awesome"
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Hackaday (Dec 2025): "Cheap and Aggressive DRAM Chip Tester"
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Elektor Magazine (Dec 2025): "Ram-Tester Is an Open-Source DIY Solution for Retro Computer RAM"
Why this tester?
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No chip knowledge needed – Set the pin count via DIP switch — the tester auto-detects the chip type. No deciphering chip markings, no menus, no datasheet lookups. Grab a chip from the parts bin, plug it in, get a result.
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Fast – Most tests complete in under 10 seconds. Full 41256 test in 7.4s. Test a whole tray in minutes, not hours.
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Thorough – Checkerboard patterns, crosstalk, address-line verification, real retention-time testing, CAS-before-RAS refresh, fast page mode, static column and nibble mode, ground-short detection — plus a full March C- test for static RAM.
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Configurable – On-device settings menu: continuous loop/stress testing (incl. CBR refresh-counter check), 32K half-good detection on/off, and OLED dimming for long runs.
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Practical – Clear good/bad result. A DRAM chip can't be repaired – you need to know if it works, not why it doesn't.
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Safe – Short-circuit protection, current limiting, ground short detection. Self-test mode included.
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Fully Open Source – Hardware, firmware, schematics on GitHub. No black box, no vendor lock-in.
How it works
- Insert the chip (16, 18 or 20 pins, DIP or ZIP).
- Set the DIP switch to match the pin count.
- Connect USB-C power (or press RESET if already powered).
- Read the result: OLED display shows a plain-text report, or LED blink codes (green = pass, red = fail).

Supported chips & test times
| Chip |
Capacity |
Pins |
Test Time |
Notes |
| 4027 |
4K × 1 |
16 |
0.2s |
Requires 4116 adapter |
| 4816 |
16K × 1 |
16 |
0.7s |
|
| 4116 |
16K × 1 |
16 |
0.5s |
Requires 4116 adapter |
| 4416 |
16K × 4 |
18 |
1.7s |
|
| 3732 |
32K × 1 |
16 |
1.8s |
Half-good 4164s (OKI/TI) |
| 4532 |
32K × 1 |
16 |
1.8s |
Half-good 4164s (OKI/TI) |
| 4164 |
64K × 1 |
16 |
1.8s |
|
| 4464 |
64K × 4 |
18 |
5.2s |
|
| 41256 |
256K × 1 |
16 |
7.5s |
Nibble mode (41257) |
| 44256 |
256K × 4 |
20 |
3.5s |
DIP & ZIP, static column (44258) |
| 411000 |
1M × 1 |
18 |
23.8s |
DIP only |
| 514400 |
1M × 4 |
20 |
12.0s |
DIP & ZIP, static column (514402) |
| 2114 |
1K × 4 |
18 |
0.4s |
SRAM – insert rotated 180° |
Test times include OLED display. Without display approx. 1s shorter.
The 2114 is static RAM: Vcc/GND are swapped vs. DRAM, so it must be inserted rotated 180° (Pin 10 on the ZIF Pin 1 marking) – see the manual.
Full compatibility list: compatibility.md on GitHub
What's in the box
- Pre-assembled V3 PCB with all SMD parts soldered
- Programmed and tested microcontroller with latest firmware
- All parts to complete the tester (ZIF socket, OLED display, DIP switch, ZIP sockets)
- Instruction leaflet with self-adhesive foam pad for the finished PCB
Product options:
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RAM Tester Only – Complete kit for all supported RAMs except 4027/4116
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with 4116 Adapter – RAM Tester + 4027/4116 adapter board kit
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4116 Adapter Only – Requires RAM Tester with firmware ≥ 3.x.x
What you need
- Soldering iron (50 solder points, +36 for 4116 adapter)
- USB-C power supply (5V, 1A) with cable
- Assembly video and docs on GitHub
Shipping
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Switzerland: Swiss Post Economy.
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Europe: Swiss Post Economy. There may be VAT/Import Duties!
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USA: Swiss Post PDDP (Delivered Duty Paid) – all import duties prepaid. NO additional fees on delivery.
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Rest of World: Check your country's import regulations regarding import fees.
Ships within 2–3 business days from Switzerland.
⚠ Laboratory / Maker Kit – Not a consumer product. Open-source kit, sold as-is. Operate only with certified USB-C power supply. Not for unattended use.
Voluntary take-back: Devices may be returned to the developer for recycling. Shipping costs borne by sender. No WEEE scheme participation.