Frame signal from motherboard recorded by web7days at 0:14 second in PCI AD A34, see the short burst signal recorded on the oscilloscope. In BIOS, frame signal can be obtained in pin 31. The FRAME signal (the AGP frame period and the PCI frame period) these two are the CPU power supply, the clock, after the replacement normal, CPU starts to work, through CPU, northbridge, southbridge, interface circuits and so on PCI transports the data, the order is northbride CPU- south bridge – BIOS. The FRAME signal for the northern bridge an important signal which transmits toward the south bridge, if this no signal found, north bridge may have problems, we to consider power supply, clock, or other. If this signal found, in addition south bridge itself working condition satisfies, south bridge does not work, that is south bridge has a real problem
