Kenwood NX-420 K Service Manual

Contents

NX-42031TROUBLE SHOOTINGŪ The LCD displays control 1The LCD does not function even if it is exchanged with the Display unit. 1It is unlikely that the BGA parts are broken.Points to be checked Normal voltage/LCDCS R640 3.3V0V3.3VIf the /LCDCS is 0V or 3.3V, the ASIC/FLASH/SRAMmay be broken.When a normalvalue is confirmed.When an abnormalvalue is confirmed.Ū When an error display appears on the LCD 1The LCD displays “ERR 1”. An error occurs when the ASIC internal RAM readsor writes. The ASIC may be broken.The LCD displays “ERR 2”. An error occurs when the DSP internal RAM readsor writes. The DSP may be broken.The LCD displays “ERR 3”. An error occurs when the SRAM internal RAM readsor writes. The SRAM may be broken.Ū When the LED color changes red and orange alternately *21: K3 model2: K modelA warning tone sounds The frequency data was not written.(Unprogramming)A warning tone does not sound An error occurs when the ASIC internal RAM readsor writes. The ASIC may be broken.An error occurs when the DSP internal RAM readsor writes. The DSP may be broken.An error occurs when the SRAM internal RAM readsor writes. The SRAM may be broken.oror■ Descriptions of signal names1) RST(RESET) : ASIC reset signal LOW Reset2) /BINT : Battery fi nal voltage monitoring LOW Final voltage3) PSW : Power switch signal HIGH ON4) /FRST : FLASH reset signal LOW Reset5) SBC : Switch B control HIGH ON6) /DRST : DSP reset signal LOW ResetReplacing TX-RX Unit■ TX-RX unit InformationModel Name Original TX-RXunit NumberFor Service TX-RXunit NumberNX-420 (K,K3) X57-8370-10 X57-8370-11■ Method of confi rming “Original TX-RX unit” and“Service TX-RX unit”R1R2X57-837Component side