Apple M8347LL/A User Guide - Page 158

Troubleshooting Symptom/Cure Tables: Startup Problems Before the Finder Error Beep(s) If you hear from one to five error beeps at startup with no boot chime, you have a hardware problem. The table explains how to troubleshoot and repair an iMac unit that sounds one or more error beeps at startup. Possible Cause Possible Fix No DRAM is installed or detected. Do you hear one error beep at startup? Yes: Follow these steps to resolve the problem: 1. Make sure the DRAM are PC-100 SDRAM. Reseat the SDRAM and try again. 2. If no SDRAM is present, install a known-good PC-100 SDRAM and try again. 3. If DRAM is present, replace DIMM one at a time, with a known-good PC-100 SDRAM. No: Go to next step. Incompatible RAM is installed. Bad RAM. Bad ROM. Do you hear two error beeps at startup? Yes: Verify that only SDRAM PC-100 DIMMs are installed (The iMac ships with PC-100 SDRAM memory and is not compatible with EDO DIMMs.) No: Go to next step. Do you hear three error beeps at startup? Yes: Replace the existing SDRAM one DIMM at a time with known-good PC-100 SDRAM. No: Go to next step. Do you hear four or five error beeps at startup? Yes: Replace the logic board. No: If you do not hear any error beeps at startup, you have a different problem and should refer to one of the other troubleshooting tables in this chapter.