II. Troubleshooting of main troubles
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No picture, no sound, no VFD
display
Check if power supply of MT1389
3.3V, 1.8V is right?
Check the voltage of power board,
and check if the decoding board is
short circuit to the grounding.
If the clock signal output XO
and XI is right?
Check if clock oscillating circuit
27M crystal oscillator, C275,
C276, R224, R248 are damaged?
Check if reset signal URST# is
in 5V high level?
Check if the reset circuit which is
comprised by HCU04 and Q204 etc.
is in working order?
Check if I2C bus, SDA, SCL 3.3V
voltage is right?
Check if the AT24C16, CS4360,
MT1389 SDA and SCL are short
circuit to grounding, if R259 and R260
are in working order?
Check if SDRAM CLK, CS, RAS, CAS,
WE communication signals are right?
Check if FLASH ROM, URST, DCE,
DRD, DWR signals are right?
Check if the connection between
MT1389, FLASH, SDRAM is right?
Check if the MT1389, SDRAM and
FLASH are damaged?