LG bc989p troubl free download

File name bc989p_troubl.pdf

ELECTRICAL TROUBLESHOOTING GUIDE 1. Power Circuit(SMPS) (1) No 5.3VA. No 5.3VA. YES NO Replace the F101 Is the F101 normal? (Use the same Fuse). YES NO Is the BD101 normal? Replace the BD101. YES NO Is the R101 normal? Replace the R101. YES Does the oscillation waveform appear at NO Is Vcc(about 13~15V) permittable at the the IC101 Pin 1? IC101 Pin 5? YES NO Check or Replace the D103. NO Is there DC voltage at the IC101 Pin 4? Replace the IC102. YES NO Is there about 2.5V at the IC103 Vref ? Replace the IC103. YES NO Is the D106 normal? Replace the D106. YES Check the Main PCB 5.3VA Line short? 3-3 7. Power Circuit(SMPS) (2) No 12VA.(Capstan) No 12VA. YES NO Does 5.3VA work normally? Check whether 5.3VA is out of order. YES NO Is the D109 normal? Replace the D109. YES Check 12VA Line of the Main PCB short. (3) No 12VA (CANAL, Buffer) No 12VA. YES Is Vcc(about 14VA) put into the Q155 NO Replace the Peripheral Circuitry of Q155. Collector? YES Is Voltage(about 14V) put into the Q155 NO 1. Check the ZD151 and the Peripheral Base? Circuitry. 2. Check the R105. YES Check or Replace the Q155. 3-4 7. Power Circuit(SMPS) (4) No 5VT(5V) No 5VT.(5V) YES Is 5.3VA put into the Q152(Q151) collector? YES NO Is the Q163(Q162) Base "H"? Che