Troubleshooting Guide - Elenco Electronics FG-600K Assembly And Instruction Manual

In each of the following steps, start with the switch and pots as shown on the previous page.
2) OUTPUT WAVEFORMS
Connect an oscilloscope probe to the square wave output. You should see about 8V peak to peak square wave
of a little over 15Hz. Connect the oscilloscope probe to the sine/triangle wave output. You should see a sine
wave of approximately 3V peak to peak or greater. Set the Sine/Triangle switch to the Triangle wave position.
You should see a triangle waveform of approximately 3V peak to peak or greater. In both sine and triangle
waves, the frequency is also a little over 15Hz.
3) FREQUENCY CONTROLS
6 range settings, vary the FREQUENCY pot from max to min and check that the frequency varies according to
Table 1 on page 12 or greater.
4) AMPLITUDE CONTROLS
Set the switch and pots as in Step 1. Connect the oscilloscope to the sine/triangle wave output and vary the
AMPLITUDE pot. The sine wave amplitude should vary from near zero to approximately 3V peak to peak or
greater.

TROUBLESHOOTING GUIDE

A) NO SINE/TRIANGLE OR SQUARE WAVE OUTPUT
1) Check the soldering on switch S3.
2) Check the soldering on IC U1.
3) Check for +9V on IC1 pin 4.
4) Check that U1 is not installed backwards.
5) Check all of the values and soldering on R1, R2, R3, R4, R5, R7, R8, R9, C8, and C9.
B) WRONG FREQUENCY ON ANY RANGE SETTING
1) This indicates a wrong value capacitor in the bad range position.
C) SINE/TRIANGLE SWITCH DOESN'T WORK
1) Check the soldering on switch S2 and R6.
2) Check the value of R6.
D) AMPLITUDE CONTROL DOESN'T WORK
1) Check the soldering on R3, R7, R8, R4 and R9.
2) Check the values of the above mentioned components.
E) FREQUENCY CONTROL DOESN'T WORK
1) Check the soldering on R1 and R2.
2) Check the values of the above two resistors.
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