Disassemble, regulated output voltage 3V to U200MOKUAI (TXVCO) the 5 pin power, its 7 foot grounded. Refer to Figure 7 using frequency U200 measured 6 feet, has normal GSM frequency band signal output, judging by the U200 's own normal, power on the actual, call 112 and, using oscilloscope measurements U200 5 foot, power supply pulse, but the rate is only about 1.2V, digital power supply anomaly. Closer inspection an C391 capacitors, U200 supply returned to normal boot can make telephone calls, troubleshooting.WEbservice manual download site