System locks up after power–down/power–up
If the power supply does not drain below 0.7V, the CMOS components on
the card will act like diodes and forward bias. This is typically caused by
using power supplies that have large output capacitors. Either use a
different power supply that discharges faster, leave the power off until the
supply has adequate time to discharge or place a 100 ohm, large wattage
resistor across the output capacitor.
Octagon supplies are designed to ramp up fast, discharge fast on power–
down and to regulate properly under a no load condition.
LED signaling of “beep” codes
Description
The PC–600 has bicolor LEDs (CR3 green and CR5 amber) that are used by
the BIOS to indicate the BIOS processing state.
Immediately after the PC–600 powers on, the CR5 amber LED is on and
the CR3 green LED is off. Once the card boots, the CR5 amber LED turns
off and the CR3 green LED is on.
If the BIOS finds an error during the power on self test (POST) the CR5
amber LED is flashed in a pattern indicating the POST code failure. The
visual beep codes are defined in Table 20–1.
Count the number of flashes in each of four sets. Subtract one from each
set, the resulting number matches the POST error found in the Table 20–1.
For example:
Flash-Flash pause
Flash-Flash-Flash-Flash pause
Flash-Flash-Flash-Flash-Flash pause
Flash-Flash-Flash-Flash
Is counted as 2-4-5-4. After subtracting one from each set the result is 1-3-
4-3. This is a failure of the first 64K of base RAM.
121