Lexmark C720 Service Manual - Page 187

5024-001 3. Diagnostic Aids This chapter explains the tests and procedures to identify printer failures and to verify repairs have corrected the problem. The following diagnostic aids can be initiated at POR by pressing certain button sequences. These tests are also available in diagnostic mode. See "Diagnostic Mode" on page 3-5, for more information. Disabling Download Emulations Error Code 964: Download Emulation CRC Failure. Checksum failure detected in the emulation header or emulation file. Error Code 965: Download Emulation Outdated. Time stamps indicate the download emulation and RIP code are incompatible. To help resolve Download Emulation problems, the following steps are necessary to instruct the printer to POR without activating any download emulations. To disable the download emulation: 1. Turn the printer Off. 2. Press and hold the Go and Menu buttons. 3. Turn the printer On and release the buttons once "Performing Self Test" displays. After POR completes, the CONFIG Menu is displayed. 4. Select Download Emuls from the menu. 5. Select the Disable Option. The printer automatically exits the configuration menu and initializes as if the download emulator were not installed. Once the printer is idle, a new emulator can be downloaded again. 6. Program the download emulation into the code overlay SIMM. 7. If these steps do not resolve the problem, replace the code overlay SIMM and re-download the emulation. Diagnostic Aids 3-1