Troubleshooting Guide - Ramsey Electronics UAM4 Manual

frequencies to see if you experience any differences, but chances are you
won't notice a change. The primary reason for changing the mode would be
interference on nearby electronic equipment or (this is very unlikely) if your
neighbor starts complaining that your amplifier is interfering with his Hi-Fi
system. We have provided the ability to change the mode mainly for your
learning/experimental purposes. If the MAX9708 is placed in a system that is
sensitive to the high frequency signal or uses the same frequency as the
MAX9708, the ability to change the mode may come in handy. If you want to
learn more about this technology, a lot of excellent resources can be found on
the internet by searching for "Class D amplifier" and/or "switch mode
amplifier."
SWITCHING FREQUENCY JUMPER CONFIGURATION
TROUBLESHOOTING
If you find that your UAM4 is not functioning as expected the first thing to do is
make sure there are no solder bridges between components and board
traces. Since most of the components in this kit are surface mount and some
are placed very close to each other there is a good possibility a bit of solder
has found its way to the wrong place. Also make sure all of the components
are installed in the correct direction and locations. Over 95% of the problems
found with returned kits are caused by solder bridges and components
installed improperly. A visual check with a good magnifying glass will often
reveal the problem.
Check that the jumper between 'JP1' and 'JP2' is installed on the bottom
of the board and soldered.
Check that the Jumper between JP1 and C 5 is installed properly.
Check all of the resistor values. There are only two resistor values used
in the UAM4. They are a 1K ohm, marked as 102, and a 10Kohm,
marked as 103. While the UAM4 will probably still work even with an
incorrect resistor, it is important that these two values are present and
they are in the correct locations.
The small surface mount capacitors are not marked, which makes it a little
FREQ (KHz)
1
200 X
250
160 X
**200(SSM)
H1
2 3 1
X X
X X X
X
X X
UAM4• 26
H2
2 3
X
X
X X
X X