KEF hfe kef kit relay buzz rework procedure free download

File name hfe_kef_kit_relay_buzz_rework_procedure.pdf

KIT200 / KFDVKT202-05CP31 Rework Procedure Purpose : Rework on the C383 overheated by R371 and replace with new 85C relay PCB. Safety Precaution : Please disconnect the AC power cord before rework. 1) Remove panel screws (12pcs) Pull out the Amp Module carefully from cabinet 2) Disconnect the wire harnessings attached to the amplifier as shown in below photos. CN8 CN305 SPK2 Gnd 2 CN 306 Spkout CN 201 CN 202 3) Remove 2x screws from relay board and pull up the relay board. After Removal of the Relay Board Screw Screw 4) Replace C383 / R370 / R371 a) Cut off the leads of the original C383 / R371 & R370 on component side of Amp board b) Replace capacitor C383 from 50V 47uF 20% to 50V 10U 20% SHOEI 105 i Add Oil sleeve to the pins of new C383. Specification (ID=1MM L=10mm*2pcs) ii Lap solder the new C383 (50V 10uF 105C) with same polarity as original shown on the PCB printing. iii Add yellow glue to bond new C383 onto neigboring Big E-Cap or PCB Surface. c) Replace resistor R371 from 300ohms/1W to 2W 1.5K 5% METAL OXIDE i Add Oil sleeve to the pins of R371. Specification: ID=1MM L1=10mmL2=5mm ii Lap solder the new R371 (2W 1k5ohm 5%) d) Replace resistor R370 to a bare jumper wire or 0R0 link. i Lap solder a jumper wire on R370 Before Change R370 After Change R371 R371 C383 R370 C383 Bond new C383 onto side of neighboring Big E-Cap 5) After completing step4, replace the New Relay board with +85C Relays and tighten up the screws. New Relay board Old Relay board 6) After replacing the New relay board, insert back all the connectors. CN202 SPK2 Spkout(Red wire) CN201 GND2(Red/black wire) GN306 GN305 GN8 7) Assemble back the amplifier and the rear panel. w 8)