[time-nuts] Odd FTS 4060 Behavior

ewkehren at aol.com ewkehren at aol.com
Sun Jun 13 19:42:11 EDT 2010


Adrian, maybe I missed something which oscillator does your unit have?  Bert





-----Original Message-----
From: Adrian <rfnuts at arcor.de>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Sent: Sun, Jun 13, 2010 6:08 pm
Subject: Re: [time-nuts] Odd FTS 4060 Behavior


John, 
 
yep! 
 
The OCXO out of the 4060 and connected to a bench power supply with no tuning voltages applied had to be trimmed to get on 10 MHz. 
After a while it started temporarily jumping to -1.4E-07, which could be reversed or provoked by knocking it on the head. 
 
I decided to disassemble it and found a neatly built dewar insulated oven inside. I just didn't like the solder joints of the gold plated edge connector pins on the two PCB's inside the oven that had separated on the component side from some of the pins. So, I resoldered them and stuffed everything back in the jar. After powering it up, I had to trim it back by about the same amount it needed in the beginning when it appeared to be in 'failure mode'. At the moment it appears to be no more vibration sensitive, but that doesn't necessarily mean I got it fixed. 
 
Now it's back in the 4060 (without readjusting it, the tuning voltage is almost exactly at center scale!), and we shall see if it behaves or not. 
 
Adrian 
 
John Miles schrieb: 
> Sounds like the OCXO has a jumping problem, going too far out of range for 
> the CS loop to correct. Have you watched it for a long period of time with 
> the loop turned off? 
> 
> -- john, KE5FX 
> 
> >> -----Original Message----- 
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On 
>> Behalf Of Adrian 
>> Sent: Saturday, June 12, 2010 8:03 AM 
>> To: time-nuts at febo.com 
>> Subject: [time-nuts] Odd FTS 4060 Behavior 
>> 
>> 
>> I have a FTS 4060 Caesium Frequency Standard that I never managed to get 
>> working properly. 
>> When powered on, it locks properly after some 10 minutes and keeps 
>> running until it jumps off by about +1E-7. That is, the 10 MHz output 
>> then reads 10,000,001 Hz, and the red alarm light is on. 
>> When I tried it yesterday again, it worked for about 2 hours before the 
>> shift appeared. Oddly enough, the green 'Locked' light was still on. 
>> This happens every 2...20 hours. 
>> 
>> Any ideas what could cause that failure? 
>> 
>> Adrian 
>> 
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