I can't read the clock in my radio during the day so I stuck an LCD>clock to my dashboard. Problem was I could not>read it as night without pressing a button to light the display. >Besides, it lost about a minute a week.>

I thought I found the solution in the JC Whitney LED DIGITAL QUARTZ>CLOCK SKU#ZX812798R $15.95. I cut a hole in>my dash and installed it only to find two problems:>1. I could not read it during the day - The LED display was very dim.>2. It gained about a minute a week.>

This digital was the only one I could find after an extensive search>so I resolved to fix these problems.>

I ordered another clock to experiment with and took it apart. The>first problem resulted from a 0.80 thick plastic>lens in front of the actual LED. It was red and dimmed the light from>the LED behind it. I cut a slot the actual>size of the led in a piece of black plastic the same thickness - a>clear piece could be used but the the PC board>the LED is mounted on would be visible. I assume this is why they used>the red color on the lens.>

The second problem was a little harder to figure out - I looked up the>quartz crystal (3.93216 MHz ) which the clock>depends on for accuracy.>There is a pair of capacitors used to load the crystal and the>required value was specified at 17 pico-farad. >

I found useful information on crystal timing at:>http://www.maxi­m-ic.com/appnotes.cf­m/appnote_number/555­>The first thing was that a clock running fast can be adjusted by>increasing the capactor values. The second thing>was a formula the total value for capacitors hooked up in series. If>they are the same value, the total value>is half the value of the individual capacitors.>

I found the load capacitors in the clock were 15 pf which calculates>out to a load value of 7.5pf versus the 17pf>specified. I substituted two 33pf ceramic capacitors for a calculated>value of 16.5pf - much closer to the 17pf>specified. The result was the clocks (I changed both) now gain or>loose 1 second or less in a week of testing.>

You may wonder why I went to this much trouble - >1. I could not find another clock that might work.>2. I had cut a hole in my dash which the clock fitted into.

I think he merely wanted to impress all of us with his research on> capacitors, in which the values of the reciprocals add up when placed> in series. If you only have two, that reciprocal is one half. Big> deal.> I'm not knocking you Steamer. I love to tinker for the experimental> value and to customize everything about as well.>