I'm not sure where you want the two ends of C8 to go.

In parallel with SW8.

 

I replaced the DS1307 with one of my two other spares. That brought back all functions. However, now the original problem remains: the timer is still slow.

It appears two of the DS1307's don't want to play at all, and this one has the clock running slow.

 

My only guess at this point is either the crystal is the wrong frequency, not making contact fully, or simply bad. Perhaps another bad DS1307 is another possibility. Not sure what else could be going on.

 

My only guess at this point is either the crystal is the wrong frequency, not making contact fully, or simply bad. Perhaps another bad DS1307 is another possibility. Not sure what else could be going on.

I'll try some of the other crystals tonight.

 

Does your work area have carpet, or your work space a little "static-y?"

joe

I replaced the DS1307 with one of my two other spares. That brought back all functions. However, now the original problem remains: the timer is still slow.

It appears two of the DS1307's don't want to play at all, and this one has the clock running slow.