[time-nuts] HP5065A digital clock info

EWKehren at aol.com EWKehren at aol.com
Wed Sep 28 01:10:10 UTC 2011


Sorry Ed  you are wrong. Hp generates a 65 Hz signal that advances the  
internal prescaler 49 counts and uses the 1 pps output to stop the 65 Hz  
output at count 49 and waits for the internal 1 pps to go to 50 and advance the  
second digit one count. Sounds crazy but it works, makes the clock advance 
in  perfect sync with the internal second generator.
Bert Kehren
 
 
In a message dated 9/27/2011 8:16:43 P.M. Eastern Standard Time,  
eb at telight.com writes:

The  original clock IC is probably OK - I needed to ID it to figure 
out how to  modify the circuit for new power and interface. I have a 
couple of  (probably OK) pulled MM5315s also, which could sub with a 
slight pinout  rearrangement if needed.

After looking at the manual, I realized that I  did look at this 
series of parts way back, but didn't get the connection  because I 
thought it would have to be a type that takes 1 Hz input rather  than 
50/60 Hz. I see now that they were used in the "set" mode, bypassing  
the internal divide by 50/60.

The clock module I have is the type  with a 555 used as a one-shot for 
normal operation, or as an oscillator  for fast setting. I think this 
is probably the newer of the designs, since  it is simpler.

Ed   


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