Troubleshooting Tips - Ramsey Electronics URC1 Owner's Manual

TROUBLESHOOTING TIPS:

PROBLEM: None of the displays light, VR1 regulator gets hot fast.
SOLUTION: You likely have a short across the power supply or you have a
component placed in the incorrect orientation. Check all of your parts to
make sure they correlate with those in the parts layout diagram. Also
check your power supply polarity to make sure that the polarity is
correct.
PROBLEM: None of the displays light, but VR1 remains cool.
SOLUTION: Using an oscilloscope or a frequency counter, verify that there is
a 3.579 Mhz signal on pin 10 of U5 and pin 1 of U6 of approximately .5
volts peak to peak or greater. If you cannot check this, check pin 9 of
U6 for 4 to 5 volts DC. Also check pin 19 of U2 for 5 VDC. If not, check
VR1 for 5 volts output with at least 7 volts input.
PROBLEM: Some displays and segments light, others do not when I run all
eights into the unit.
SOLUTION: There is only two possibilities for this problem. First check with a
magnifier to verify that there are no shorts or cold solder joints on the
display board behind the displays. Also check the interface between the
two boards to make sure everything has been done correctly. Second,
you may have a faulty display. Since this is very unlikely, check all of
your solder joints again to make sure they are OK. If everything is fine,
then see the warranty section of the manual.
PROBLEM: Everything is OK, but no tones can be detected.
SOLUTION: Check around U4 and J1 for bad solder joints. Also make sure
that your crystal is marked 3.579 and not some other number. Also
check your audio connections and the audio level to the unit.
PROBLEM: Levels don't go all the way up to 5 volts.
SOLUTION: This was necessary on the kit to allow all 256 steps to be noticed.
If a higher output voltage is required, remove D11 and put a jumper in
it's place. Now you will notice that a value entered from 245 on up
represents full scale.
PROBLEM: Outputs only go to half voltage, some outputs don't work at all,
resistance values don't change.
SOLUTION: More than likely this is an assembly error, usually solder bridges
or cold solder joints surrounding CON1 and CON2. A fine tip soldering
iron and solder wick will help you to remedy these problems, as well as
patience and good troubleshooting skills.
URC1 • 15