two ways to make a kit easier to fix

1) take a picture of the board
 

I've found a picture valuable in spotting trouble with multiple customer kits.  With high-quality cameras in cellphones I've even been able to spot THE cold solder joint in a customers kit.  And when a customer has inserted a part into the wrong place on the board it's a lot easier for me to recognize this with a picture.  And with "high-speed" internet even the multi-megabyte picture file sizes are easy to send/receive.

 

2) take a measurement of the power supply current
 

This is a sort of sanity check, especially for any CMOS based kits.  When the clock to the CMOS is stopped (often called sleep) the current should be essentially zero, just leakage currents and possibly regulator quiescent current.

I found this really useful recently when I was attempting to "migrate" a kit from one PIC chip to another.  Migration is always an adventure because the PIC vendor, Microchip, likes to change things.  In this case it was a clock crystal based circuit (32.768 kHz) that drew 18 uA at 3V with the old PIC chip.  The new PIC chip was supposed to be lower power but the readings were more like 440 uA or more than 20 times the previous PIC chip.

Clearly something was wrong.  In addition, the analog inputs weren't working correctly, the PIC was giving inaccurate readings.

I finally realized that the internal pullups of the PIC were turned on by default with this new device.  These pullups are the equivalent of a resistance tied to the +3V power supply so they would account for both the analog reading problem AND the high power supply current.

I turned off the internal pullups with an added instruction and the migrated chip began to work !  The power supply current decreased to 9 uA at 3 V.

It can be really satisfying to fix a problem like this (even though I was the cause of it in the first place :)

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm