Tomcat
EFM
electronics for music
(c) EFM ele4music.com
Assembly
is a simple matter of soldering the parts on the board and adjusting two trimmers.
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Install the jumpers shown as thin black lines on the overlay.
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Solder the resistors in place and then the diodes
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If you decide to use IC sockets solder them in now. You should always use a socket for the PIC (U5). I
prefer to install semiconductors last. It's a good policy.
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Install the capacitors.
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Install all remaining solder mounted parts. Including jacks, pots, switches, transistors, and ICs. The
regulators barely get warm and do not require heat sinks.
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Plug the ICs into their sockets.
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Once the parts are installed on the board it's time to do the setup.
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Use a test clip or computer type jumper block to connect the two header pins labelled SW1 on header 1.
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SMOKE TEST! Be ready to pull the power plug if anything smokes or feels hot to the touch. Plug the
transformer into the wall and then plug the power plug into the power jack. If nothing smokes gently touch
the tops of the ICs to see if anything is running hot. BE CAREFUL! A hot running IC can easily cause 1st
degree burns or blister your fingers.
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If you have any problems unplug the unit and check your work for solder bridges or unsoldered pads.
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If everything looks good so far set your meter to DC volts and check for +/- 12VDC at header 3.
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If you have the correct voltages, connect your meter to header 2 V-Ref. Adjust trimmer T1 for -10.56VDC.
Pull the power plug to turn the unit off.
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Attach your midi controller to the midi jack. Make sure all 4 switches on S2 are off (open) and that the
controller is set to midi channel 1.
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Plug the output jack into your monitor amplifier making sure the levels on both the amp and the synthesiser
are turned down. WARNING! This synthesiser puts out very high audio levels and could damage your
speakers if the amplifier is turned up too loud.
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Set the unit to it's basic patch.
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Plug the power plug back in.
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Play a few keys you should hear the output through your monitor amp.
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Press C5 and then C6 to hear the octave. Adjust T2 until the octave scale is correct.
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Let the unit warm up for 5-10 minutes and readjust T2.
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Play around with the controls to make sure all functions work correctly.
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Congratulations! You have built a working synthesiser. Attach the board to your panel or case using 4-40
screws and nuts. Use header plugs to attach the power switch and LED header 1. If you decide to use them
connect the CV outputs header 2 to output jacks.
