Macintosh SE/30 Troubleshooting: Difference between revisions
No edit summary |
|||
| Line 3: | Line 3: | ||
=== "Simasimac" – Horizontal Stripe Pattern === | === "Simasimac" – Horizontal Stripe Pattern === | ||
[[File:Simasimac issue.jpg|thumb|Macintosh Simasimac]] | |||
The notorious "Simasimac" manifests as horizontal black-and-white stripes and no startup chime, typically due to capacitor leakage disrupting reset circuits. Clean and reseat ROM and RAM SIMMs; replace the PRAM battery if below 3 V. Conduct thorough trace inspections, especially near capacitors, using a multimeter or oscilloscope to verify continuity on CPU address/data lines. Check for a stable 16 MHz clock at the CPU and a correct reset pulse sequence. If persistent, examine the Apple Sound Chip (ASC) at UB11 or the Bourns network filter RP2. Repair or replace damaged traces, capacitors, or suspect components accordingly. | The notorious "Simasimac" manifests as horizontal black-and-white stripes and no startup chime, typically due to capacitor leakage disrupting reset circuits. Clean and reseat ROM and RAM SIMMs; replace the PRAM battery if below 3 V. Conduct thorough trace inspections, especially near capacitors, using a multimeter or oscilloscope to verify continuity on CPU address/data lines. Check for a stable 16 MHz clock at the CPU and a correct reset pulse sequence. If persistent, examine the Apple Sound Chip (ASC) at UB11 or the Bourns network filter RP2. Repair or replace damaged traces, capacitors, or suspect components accordingly. | ||
| Line 17: | Line 18: | ||
==== Checkerboard Pattern ==== | ==== Checkerboard Pattern ==== | ||
[[File:Macintosh SE-30 Checkerboard.png|thumb|Macintosh SE/30 Checkerboard]] | |||
A checkerboard screen usually signals ROM issues. Clean and reseat the ROM SIMM, ensuring compatibility (original SE/30 or Macintosh IIsi ROM). | A checkerboard screen usually signals ROM issues. Clean and reseat the ROM SIMM, ensuring compatibility (original SE/30 or Macintosh IIsi ROM). | ||