Casio CTK-480 Service Manual

Also see for CTK-480: Operation manual Operation manual

Contents

Casio CTK-480 Service Manual Manual pdf 7 page image

— 7 —INITIAL RESET CIRCUITWhen batteries are set or an AC adapter is connected, the reset IC provides a low pulse to the CPU.The CPU then initializes its internal circuit.CPUMSM 6755B-06LSI101RESETReset ICRE5VA35AIC102VDDBattery SetTROUBLESHOOTINGNature of Trouble Faulty Block Cause/RemedyNo power Power supply circuit Faulty IC101. Replace IC101.Faulty D106 ~ D109. Replace D106 ~D109.Faulty Q101 ~ Q104. Replace Q101 ~Q104.Power switch Poor contact. Clean the contacts.Power jack (J101) Open J101 or poor soldering. ReplaceJ101 or resolder.No sound at all Power Amp (IC101: LA4596) Open or shorted IC101. Replace IC101.CPU (LSI101: MSM6755B-06) Faulty LSI101. Replace LSI101.Oscillator Faulty Q111. Replace Q111.Open X101. Replace X101.Certain keys or switchesdo not functionKey and switch matrix Open circuit on KO or KI line.Replace keyboard PCB assembly.CPU (LSI101: MSM6755B-06) Faulty LSI101. Replace LSI101.A certain key or switchdoes not functionKey and switch matrix Dust on the contact.