屡烧电源模块的常见原因和故障排除（国外英文资料）.docVIP

屡烧电源模块的常见原因和故障排除（国外英文资料） This article is quoted from HLJLNK @126 common causes and troubleshooting of recurring power modules Boot no - a common cause and troubleshooting of STR - F6707 Common for (1) without the 300 v, 300 v filter capacitance C90l (100 uf / 400 v) failure, R901 current-limiting resistance (5.6 Ω / 5 w) open, STR - F6707 internal damage of power tube breakdown, R905 Ω / 2 w starting resistance (820 k) damage. If the boot is fired several times, the STR -s6707 may be the result of a reduction in the size of the C901. (2) the konka F2109C machine of positive feedback circuit components are: switch the pet-name ruby and 7 transformer, VD907 (Ru2), R909 (4.7 k), C914 pf (100), 904 (Ru2) VI), C915 (pf) 820, STR - F6707 (1) feet. Therefore, the VD907 open circuit or the c914 failure should be checked, and the internal resistance leakage of the strab-f6707 should be replaced. (3) if the rectifying, filtering, starting and positive feedback circuit is normal, check the voltage control loop. The main components of the pulse width modulation (voltage stabilizer) circuit are the control of the integrated circuit N905 (SEllO). Sample stabilized diode VD990 (3.9 V); The photocoupler N903 (TLP621) and its N903, the capacitive c9ll (o. 033uF). The most common was the C911 leak, which caused STR - F6707 to stop (4) working in the open/close circuit. Check the CPU (Z90231) 35 feet, V606 (2SCl815), V998 (C1815), etc. . Q / | 8 o0 ^ % w. | if (5) + B (110 v) output is not stable, and the measured sTR - F6707 4 feet on the low side of only 10 v (normal to 18 v). It may be the result of reduced capacitance of the c912 (47uF / 50V). (6) if the ac grid voltage is unstable, the machine cannot be switched on normally, and the reason is that the optical coupling N903 (TLP621) is damaged. (7) for konka C color TV series, because its main chip TDA8841 (0 m8838) have breakdown self check and soft start slow stop function, so if encounter 3 without, can disconnect the microproc