Jeremy,
The DC voltages at U4 pins 1 and 2 are suspicious. The voltage at pin 5
is from the MCU digital outputs, so I would not be to concerned about it
just yet. However, compare the voltage at U4 pin 5 with the voltage at
U7 pin 2 - that is the same signal, and the voltages should be the
same. If they are not, then there is a connection problem.
If the U7 pin 2 and the U4 pin 5 voltages are the same, I would suggest
a replacement of U4 may be in order - but first check for a solder
bridge across C87 - that would drag the U4 pins 1 and 2 voltages down to
close to zero.
73,
Don W3FPR
On 2/2/2013 7:56 PM, JeremyJones wrote:
C62 is correct, and the path is intact. Reflowed the solder on all
connections just to be sure.
U4 readings are as follows
Pin1 = 0.111
Pin2 = 0.339
Pin3 = 0.006
Pin4 = 2.363
Pin5 = 4.99
Pin6 = 4.99
Pin7 = 4.99
Pin8 = 4.99
Pin9 = 0.001
Pin10 = 0.001
Pin11 = 0.000
Pin12 = 0.000
Pin13 = 5.029
Pin14 = 5.029
Pin15 = 5.029
Pin16 = 5.029
Pins 1, 2, 7, 8, 12, and 13 are not within the specs in the manual. Is this
a bad U4, or should I start tracing backwards?
--
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