Sharp GX20 Service Manual - Page 49

A (From page 2-42) CONFIDENTIAL GX20 More than 3.6 V output at BATT terminal (TPB336)? YES Voltage of below 1.6 V applied to SENSE terminal (TPB331)? YES Is fuse (FS301) connected? YES More than 3.6 V output at VBAT_S terminal (IC202 4 Pin), VBAT_AP terminal (Between FS401 and FS402), VBAT_BB terminal (IC202 22 Pin)? YES Voltage of below 1.6 V applied to IC102 15 pin BATT_ SENSE terminal (C188 signal side)? YES Is 4-level stack memory (IC106) properly mounted? YES 3.0 V output at VMEM (TP209), and 1.8 V output at VCORE (TP207), respectively? YES 3.0 V output at VINT (TP213)? YES 32.768 kHz properly output (at X102 connected to IC104 28 pin)? Are appearance and mounting of R132, jumper (R132 to C149), R147, C149, X102 and IC104 properly given? YES 13 MHz square waves properly output at TP414? NO 13 MHz triangle waves input to IC104 142pin? NO 13 MHz triangle waves output from IC901 36 pin? NO 2.9 V output at VTCXO (TP317)? YES TCXO (TCX951), IC901 and peripheral circuit defective. NO Battery terminal defective, adhesive foreign matter at contact battery (CN303) terminal, or bad soldering. NO Battery or battery mounting defective. NO Blowout of fuse (FS301). NO • Relay FPC_A or connector CN201 defective. • Parts connected to each VBAT line or mounting defective. NO Relay FPC_A or connector CN201 defective. NO Defective mounting of 4-level stack memory (IC106). NO Power supply IC (IC202) defective. NO IC205 or jumper (IC205 5 pin to TP213) defective. NO X102 (32 kHz oscillator), R132, jumper (R132 to C149), R147 and C149 defective, or mounting defective. Or IC104 oscillation circuit defective. YES IC102, IC103, IC403, jumper (IC102 46 pin to IC104 84 pin) and L405 defective or mounting defective. YES IC104 defective. YES Parts of IC901 36 pin to IC104 142 pin defective. NO Regulator (IC303) and C318 defective. 2 - 43