A Poedi Shi (PDIS) PDS-9256 intelligent broadcast system failed recently: after the power failure does not work when you call again, checking that is the result of intelligent broadcasting control system time wrong, because after the call on the display showing the time into "00:00", after each call to artificial school before they can work, but normally there's no need to do so before.eeLservice manual download site
eeLservice manual download site
On the reference computer motherboards CMOS clock principle, the machine should be installed in the battery to ensure that still work after a power failure the clock circuit, and failure may be due to backup battery has no charge, get a grain of batteries.eeLservice manual download site
eeLservice manual download site
Open the machine, was found on the motherboard a positive chip NXP LPC2134, VLSIVS1002D, Hynix HY27UF082G2A, 74HC573, PDIUSBD12, MC34063 and AMS1117, as shown in Figure 1. Find information: NXP LPC2134 Philips company produces, is a real-time simulation and embedded track 16/32 ARM7TDMf-S single-chip ARM MCUs; VLSI VS1002D MP3 decoder chips; Hynix HY27UF082G2A 256MB Flash chip is Hynix produced, this machine is used to store MP3 song 74HC573 is an octal 3-State latch, For front panel LED display PDIUSBD12 USB interface chip is used to communicate with the computer through USB cable; MC34063 and AMS1117 is the average of the power control chip. These chips have clock has nothing to do with the machine.eeLservice manual download site
eeLservice manual download site
In the author's wit when suddenly find PCB Board front right corner has double columns 24-pin solder, obvious back of the circuit board components. Remove the fixing screws, and overturn the PCB Board, and sure enough, the back has a marked "SD2300AP" the words of black modules, as shown in Figure 2.eeLservice manual download site
eeLservice manual download site
SD2300 series chip is a built-in crystal oscillator high precision real-time clock chip, serial interface, pin functions are shown in table 1. This series of chips at 25 ± 1 ℃ ensures that the clock accuracy is ± 5ppm (ppm represents one out of 10,000) per year less than 2.5 minutes; the chip's internal clock accuracy adjustments function.

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