AIR 486EL - raskolnikov
7 July 2014
CMOS Battery Low error
After completing memory test and installing AHA-2742 BIOS extension, AIR 486EL mainboard self-test reports
CMOS Battery Low Press F1 to continue
The NVRAM is latched read-only when VCC falls below threshhold. Some setup values reset to defaults. If the values are changed and saved, they do not persist, even during warm reboot.
The internal battery in the Dallas DS1287 RTC has failed. Replace with DS12887 or rework part with external battery. Setup values must be reset, but EISA configuration remains intact.
No interrupt from FDC with ImageDisk
When attempting to do floppy disk drive operations, ImageDisk reports
No interrupt from FDC!
Do not attempt to run ImageDisk from an MS-DOS session under Windows.
Power-on Self Test fails to complete
Machine spontaneously locks up, followed by an inability to complete self-test. The following symptoms may be observed, alone or in combination with others: front panel indicators may not operate correctly, an audible error tone may be heard, the screen may stay black or display the message,
Pin 1 of the DS12887 was bent during installation in such a way as to have been forced through the plastic housing of the socket and is thus making poor or intermittent contact with the socket pin. This discovery was a surprise, since the machine ran correctly in this state for many months before suddenly failing. Straighten the pin and reinstall.