Compaq computer switching power supply circuit

Compaq computer switching power supply circuit

Shown is the switching power supply circuit of Compaq computer , which uses a 11A94 switching oscillation control integrated circuit and an LM339 operational amplifier integrated circuit as a voltage comparator.     The basic working principle of this circuit is similar to the aforementioned circuit. During normal operation, TL494⑧ and @ pins should output pulse signals, VT1 and VI2 work in the switching state, and each winding of transformer T2, 13, and T4 should have pulse signals. If a certain DC voltage is abnormal, the rectifier and filter components should be checked along the signal flow to diagnose the fault.