Debugging issue with triangle wave generator before finishing main board testing

TRIANGLE WAVE RESULTS DON'T MATCH EXPECTATIONS

The board is generating perfect 5V rectangular (square) waves and nice looking triangle (ramp) waves, but the adjustments are not working as they should. The frequency trimmer should be able to set the frequency of the triangle waves at 160Hz but the lowest it will operate is about 250Hz. The waves are substantially above ground and the 0V adjustment that should move the bottom above or below the ground line is instead widening or narrowing the wave shape. 

INVESTIGATION REVEALED A FEW MISPLACED RESISTORS

I found a couple of resistors in the triangle wave generator portion of the board had incorrect values. Rather than change only these and risk discovering other issues in further testing, I decided to double check the values of all resistors placed on the board.

I generated a spreadsheet with the values from the schematics, from the bill of materials, and from my visual inspection of the board. This will flag all problem placements so that I can pull them off and put the correct resistor in each location. 

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