[Heath] SB-634 clock calibration with WWV?

G3OOU at aol.com G3OOU at aol.com
Sun Oct 5 11:50:55 EDT 2014

Hi Sandy
The reference frequency for the clock chip IC201 is provided by your  mains 
supply so there is no way to adjust that. Over long periods, say 24 hours,  
the mains supply is supposed to be very accurate and you can probably find 
the  spec for the US mains on the Internet. Over short periods of time the 
mains  frequency moves around a bit.
If you find that the time is changing randomly faster than expected  then 
it may be noise or pulse interference on the mains causing false triggering  
but there is a simple RC filter inside the SB634 to remove any pulses. Check 
 that the filter capacitor C202 (0.02uF) is still good.
I have a collection of service bulletins for the SB634 if you need  them.



Bob F Burns G3OOU
G-QRP 6907
Crystal Palace Radio & Electronics Club:  www.g3oou.co.uk
Technical web site: _www.qsl.net/g3oou_ (http://www.qsl.net/g3oou) 
@BobFBurns on Twitter:  http://twitter.com/BobFBurns  

In a message dated 05/10/2014 14:23:11 GMT Standard Time, ac1wye at gmail.com  

Hi,  folks.   Now that I have my timer display problem figured out, I'm  
trying to see how the clocks compare to WWV. In the Manual, there's no mention 
 of adjusting the clocks slower or faster. Anyone know if there's a way to 
do  that?

​73,    Sandy AC1Y​

Alexander N. Gerli,  Sr.

548 Allred Mill  Road

Mount Airy, NC  27030-2202

Scotsmen walk about 900 miles each  year.

A Scotsman drinks around 45 gallons of Whisky a  year.

Scotsmen get about 20 Miles Per  Gallon.

Heath  mailing  list
Heath at puck.nether.net

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