Editing Atari STE Troubleshooting Guide (section)

== RAM Fault Diagnosis (STE-Specific) ==

The STE's SIMM-based RAM makes diagnosis and replacement much easier than the soldered RAM on the ST:

<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table"
! Symptom !! Likely Cause !! Diagnostic Steps
|-
| White screen at boot || SIMM not seated; SIMM failure; SIMM socket oxidation || Remove and reseat all SIMMs. Clean contacts with pencil eraser and IPA. Try with minimum RAM (2× 256 KB in Bank 0). Try known-good SIMMs.
|-
| Reduced RAM detected || Failed SIMM; mismatched SIMM sizes; dirty contacts || Check TOS RAM counter at boot (TOS 2.06 displays memory count). Swap SIMMs between banks to isolate. Both SIMMs in a bank must be the same size.
|-
| Random crashes after warm-up || Marginal SIMM; thermal sensitivity || Run YAART or similar memory tester. Use freeze spray to identify heat-sensitive SIMM.
|-
| 2 MB detected when 4 MB installed || Bank 1 SIMMs not recognised; SIMM socket fault || Check Bank 1 socket solder joints. Swap Bank 0 and Bank 1 SIMMs. If Bank 1 position never works regardless of SIMMs, suspect socket or GST MCU bank select.
|}