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MCU
B
MCU not
programmed
Re-programming
Yes
No
Crystal no
OSC
(1)MCU not put well
(2)Crystal bad
(3)Cap of crystal
too big/small
Yes
No
MCU 3.3V
=3.0~3.6V
No
Yes
Check DC 3.3V CKT
Check Reset
waveform when
power on
No pulse
Check Reset CKT
Check if O/P
short to GND
A pulse to > 3V
Yes
No
Check if MCU
pin short or bend
Check if socket
pin bend
No
No
MCU bad
Yes
Yes
If input over
MCU 3.3+0.3V
Yes
No
Reflow
Check 4 corner are shorted
or not
Be carefully when using
probe to measure
Change socket
Not allowed
11
ViewSonic
Corporation
Co
nfidential
-
Do
Not
Copy
VG510b/s