Ramsey Electronics CW-700, Manual

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CW700
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must be aware that there can only be two “states” on a wire: a logic one
and zero. Therefore, you should measure a voltage between zero and .5
volts, or between 2.5 and 5 volts. Any reading between .5 and 2.5
indicates a possible problem and all associated components should be
checked.
ˆ The problem may be in your power supply. Make sure that you inspect it
extra thoroughly
ˆ Some voltage measurements are noted on the schematic diagram.
Problem: The LED lights and switches seem to work, but nothing happens
when I touch the paddles.
ˆ Check the touch sensitive circuit. Be sure to check the polarities and
solder connections on the diodes and U1.
ˆ
Check the microcontroller circuit.
ˆ Press program and a message number, followed by the paddles. If the
light turns red, it may be the audio circuit. Check the tone generator and
amplifier that drives the speaker.
Problem: When I press the buttons, the unit malfunctions and either stops
working or completes the wrong function.
ˆ Check to make sure that that D6 through D12 are installed properly.
ˆ Check to see that U2 and U3 are installed correctly.
Using a methodical troubleshooting technique, most problems can be solved
using common sense. A volt-ohm meter and a clear head are all that are
usually needed to correct any problem. Please understand that it is nearly
impossible to “troubleshoot” by phone. Any specific questions should be
documented and sent to us by mail.
NEW AND IMPROVED
If you are delighted by our microprocessor controlled keyer, we proudly
introduce our memory add on kit. The CW700MX allows you to store up to 32
messages. In just a few short steps, you can have eight times the memory!