If it turns out that a video card cannot be found, or, for example, the video card is not operating properly, the BIOS will send signals to the speaker instead. The old beep signals for XT and AT computers are still in use. Here is a list of what they mean (should you ever have a computer beep at you). These are for older equipment, but will give you general idea.
|No beep||Power supply, system board|
|2 short beeps||POST Error displayed on monitor|
|Repeating short beeps||Power supply, system board|
|3 long beeps||3270 keyboard card|
|1 long, 1 short beeps||System board|
|1 long, 2 short beeps||Display adapter (MDA, CGA)|
|1 long, 3 short beeps||EGA|
|Continuous beep||Power supply, system board|
|1 short||DRAM refresh|
|2 short||Parity circuit|
|3 short||Base 64K RAM|
|4 short||System timer|
|6 short||Keyboard controller Gate A20 error|
|7 short||Virtual mode exception error|
|8 short||Display memory R/W test|
|9 short||ROM BIOS checksum|
|1-1-3||CMOS write/read (or realtime clock read/write)|
|1-1-4||ROM BIOS checksum|
|1-2-1||Programmable interval timer|
|1-2-3||DMA page register write/read|
|1-2-4||SRAM test and configuration|
|1-3-1||RAM refresh verification|
|1-3-3||1st 64kb RAM chip or data line failure, multibit|
|1-3-4||First 64K RAM odd/even logic|
|1-4-1||Address line failure first 64K RAM|
|1-4-2||Parity failure first low 64K RAM|
|2-n-n||Bit n first 64K RAM low|
|3-1-1||Slave DMA register|
|3-1-2||Master DMA register|
|3-1-3||Master interrupt mask register failure|
|3-1-4||Slave interrupt mask register failure|
|3-2-4||Keyboard controller test failure|
Originaly posted at COMP.SYS.IBM.PC.HARDWARE. FAQ V1.13, From: Shaun Burnett (burnesa at cat.com) at http://www.paranoia.com/~filipg [Copyright] [Disclaimer]
Missing from the list above is "one short" -- which means "things are ok." If you do not even get a beep signal, check if the power is on, then check to see if the tiny speaker is hooked up, that is, it is plugged into the mother board. The most likely place of failure for a speaker is a break in the wire at the speaker itself. To repair this, get out the tiny-tip soldering iron.
If you get neither a beep signal or video, go check the monitor cable, the video card dip switches, or change monitors. Quite a few boards into the 386 processor era still use a B/W - COLOR jumper on the mother board. Find it and check it. Most often located between the keyboard buffer and the first (right most) expansion slot.
If you have just done something, check that the new RAM you added is properly seated, and that the new cards are seated properly. This last seems to be the greatest source of failed boots. Also check the cables of the drives. Often something else comes loose when you are fitting in something new.
At times you will run into incapable power supplies, that is, the power supply is not big enough to handle all the cards and peripherals you have attched. Since under those conditions the mother board will not be getting enough "juice" to even start anything up, nothing happens. It just sits there.
This gives you the volt-amps (wattage) requirements of the system, although very roughly. Check this figure against the wattage listed on the power supply. If the listed wattage of the power supply is 30 to 50 percent more than this rough calculation, you should be OK.
If the power supply doesn't list wattage, but gives you volts (like 117vac) and amps (like 1.7 amps), then just multiply these two figures together to get the overall wattage.