RonSympson wrote:
Question: How fast 4 hours 48 minutes? Always the same?

The clock is aproximately 4 or more hours off in 24hrs, but i is not dependent on time of day or placement of the clock in a particular room.

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kchriste Wrote:
Which diodes are getting hot? None of them should be.

The diodes are not geting hot by running the clock. I meerely heatsink them while soldering as I do every component!

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JimB Wrote:
So, if the 50/60 hz input to pin 25 is faulty in some way, it could be running on the RC oscillator, which could be (and probably is) way off frequency.

There may be a problem with the IC but I haven't been connecting the battery backup.

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AllVol Wrote:

That was my question back in the first reply. Diodes seldom need a heat sink (and if they did, where would you buy one?)

Must be I did not explain myself well in the first post... heat sinking was to protect the diode for soldering.

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Bottom Line:
Although I have checked solder points, component values, and cleaned the poard with IPA, I will do this again for the hell of it.

 

When I said the diodes would blow if not heaksinked well I meant that when soldering the components to the board. I heatsink with a pair of hemostats.

 

I have never heatsinked anything that I have soldered with my temperature controlled soldering iron and nothing has ever been damaged.

__________________
Uncle $crooge

 

The reason ronsimpson asked about being 4 hours 48 minutes off is:

24 hours X 60/50 = 4.8 hours fast.

Pin 27 should have a 900hz signal. That should not effect you problem but it is worth checking.

Pin 25 should have 60hz and I would put an o-scope on it looking for a reason why your clock is seeing >60hz. (noise)
The data sheet want 100k and .001uf, the kit wants 18k and .01uf. (very interesting) Can you find 100k and .001uf?

I think there are two roads to go down:
1) you have 50/60 problems. The error will all wise be the same.
2) pin 25 is seeing noise. The error will be different every day.

I am looking for a way of getting another 4 hours in my day. Make you a deal!

 

Well, cleaned the circuit board with alcohol and a toothbrush. I checked all solder joints for shorts or cold solder points. Still it runs about 4hrs 30min fast in a days time. it doesn't matter what room the clock is in either.

The heat sinking of the diodes I had refered to in my original post was during the soldering of the components to the board.

 

Well, I bought a 28 pin DIP Socket and a new lock IC, hooked it up and it is STILL running fast! Unbelievable...