I just bought an X6100 a week ago, and I've ruined it. 🤡 As soon as I plugged in the power supply to the radio, I smelled a burning odor, so I immediately unplugged the DC cable. Upon inspection, I found that it was using a 24V adapter, while the maximum voltage specified in the XieGu manual is 15V. However, the radio still works normally and can transmit and receive, but the built-in battery cannot be charged.
After disassembling the machine, I found that the lithium battery linear charging chip on the baseboard was damaged. The chip model is BQ2057W. Using high voltage did not cause any other damage. I suspect the reason is that most of the remaining parts are powered by LDOs with a higher voltage rating, and the maximum voltage rating of the BQ2057W is 18V.
The X6100 consists of three main parts: the baseboard, the transceiver, and the display. As shown in the diagram, it is relatively easy to disassemble, with the three boards connected by FPC cables. The IPEX connector connects the baseboard to the transceiver board. There is an unused IPEX port on the baseboard, which houses the UV amplifier tube from Philips.
After replacing the BQ2057W, the problem was not resolved. The BQ2057W is a linear lithium battery charging chip that uses a PNP transistor to charge the lithium battery. The nominal voltage of the lithium battery group is 7.4V, and the main circuit power supply is 12V. The PNP transistor consumes excess voltage and controls the charging current. The following diagram shows a typical application as described in the manual.
Measurements revealed that the NPN transistor was also damaged. The transistor model is 2SB772, with a TO126 package. During charging, the transistor dissipates some power, and the metal surface of the TO126 is connected to the chassis via a heat sink. The heat sink serves both as an insulator and a heat conductor.
After replacing the NPN transistor, the charging current recovered to normal levels when the device was in standby mode, and the battery could charge properly.
If you accidentally connect the power supply to the radio in reverse, preventing it from charging, you can refer to this article for repair instructions.
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