| Error Message | Likely Fault | Fix | | :--- | :--- | :--- | | RAM 0 BIT 0 FAIL | Lower 16K bank, Chip IC6 (D0 data line) | Replace 4116 or 4532 DRAM | | CONTENTION FAIL | ULA pin 28 (Contention logic) | Replace ULA (5C112E or 6C001E-7) | | ROM CHECKSUM: BAD | Corrupted ROM or address line short | Re-burn ROM or check CPU A14/A15 lines | | EXTERNAL BUS: FLOATING | Broken track between CPU and ULA | Inspect data bus (D0-D7) continuity | If you are repairing Spectrums professionally, you need the burnable ROM version . The tape-based test is fine, but if your Spectrum cannot read tapes (common due to failed capacitors), you are stuck.
(Note: Replace the above placeholder with your actual hosted link. For this article, we will use the conceptual path: https://archive.org/download/zx-diag-v23/zx-tester-v23.tap ) zx spectrum test program link
Published by: Retro Tech Archives
Here is the direct link to the pre-assembled 16K ROM binary: | Error Message | Likely Fault | Fix
When the dreaded black screen appears or memory errors corrupt your loading screen, you need a diagnostic tool. You need a . For this article, we will use the conceptual
But finding a reliable today is harder than it should be. Many old forums have dead links, and GitHub repositories are often incomplete. This article will not only give you a verified, working link but also explain how to run the tests and interpret the results. Why You Need a Dedicated Test Program Before we get to the download link, let's understand the difference between a game and a diagnostic. A game like Manic Miner will crash immediately if your RAM is faulty. A test program is designed to be resilient. It writes specific patterns (like $FF, $00, $55, $AA) to every memory location, reads them back, and reports exactly which chip is failing.
Without a test ROM or tape image, you are flying blind. You might replace a working LM1889 video chip when the real problem is a single bad 4116 DRAM. After combing through the archives of World of Spectrum, Sinclair Q&A forums, and modern preservation projects, the most active, updated, and comprehensive source for diagnostic software is the "Retro Test Suite" maintained by Brendan Alford (aka "RetroBreww").